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Testosterone levels show steady decrease among young US men

515 points by rasengan 6y ago

thehappypm 6y ago
Yet another symptom of the obesity epidemic.
- thatguy0900 6y ago
  That's not all of it. "Lokeshwar noted that even men with a normal BMI (18.5-24.9) had declining total testosterone levels (P < .05) during the same time frames." lack of hard physical labor in general, or modern diets just being filled with hormones?
  - nabergh 6y ago
    Isn't it a fair question to ask though whether the average BMI of those with a "normal BMI" (18.5-24.9) changed during the time frames of interest? And if it did, couldn't that still be a cause?
  - rychco 6y ago
    Lack of hard physical labor, combined with increasing average caloric intake may contribute to lower average muscle mass & total testosterone while still maintaining a "normal" BMI. I don't have evidence to support this, but this is my guess for falling testosterone within the "normal" BMI range over time (in addition to the effect of environmental pollutants on hormones).
  - likpok 6y ago
    The "real" measure of how fat you are is body-fat percentage, which can vary at a given BMI level. It's not hard to imagine that people have gotten fatter at the same BMI level, as well as people being at the higher end of the "normal" range.
- netizen-9748 6y ago
  My money is on the ubiquitous endocrine disruptors that have polluted our ecosystem
  - mamon 6y ago
    Yeah, all that soy lattes start to add up :)
    - WalterSear 6y ago
      That's a myth from the 80s.
    - netizen-9748 6y ago
      Oh, I didn't realise soy was a pollutant. Interesting.
- ravenstine 6y ago
  It's not the only cause but, from my experience, it's a big one, no pun intended. I might have made different diet choices as a young man if I knew that body fat aromatizes testosterone into estrogen. This is the primary cause for most cases of gynecomastia, which is why it's rare to see a man with breasts who isn't also overweight to some extent. Obesity is effectively feminizing a large portion of men and lowering their sexual market value. Overall, I think obesity is making people less attracted to each other, which can partially explain the decline in the rate of reproduction.
  - Coding_Cat 6y ago
    > which is why it's rare to see a man with breasts who isn't also overweight to some extent. While (assumedly) true, I feel the need to note that the reverse does not hold generally: 'man boobs' are purely fat in nearly all cases and will go away when someone loses weight. Gynecomastia is breast tissue and does not go away if you lose weight.
  - fortran77 6y ago
    In my opinion, it's the biggest problem facing us. Even this COVID pandemic would have been much less expensive without an obese population, because our hospital capacity may not have been pushed to its limits. CDC says being obese triples the likelihood a person would need hospitalization: https://www.cdc.gov/obesity/data/obesity-and-covid-19.html https://www.cdc.gov/obesity/data/obesity-and-covid-19.html I don't see a solution. We're not going to be able to use the same techniques used to get people not to smoke to address the obesity problem.
kaesar14 6y ago
Chalking this up to declining physical activity amongst young U.S. men.
- nomoreusernames 6y ago
  it mentions that they controlled for that.
  - cellis 6y ago
    how did they control for that?
    - ausbah 6y ago
      by adding it as a feature into whatever model they created likely
- srmatto 6y ago
  They said that they controlled for that in the study.
thatguy0900 6y ago
I wonder if hormones will ever become widely available for personal use, or if we will just accept a changing hormonal landscape for men and woman. I doubt any of the underlying causes of "obesity/BMI, assay variations, diet/phytoestrogens, declined exercise and physical activity, fat percentage, marijuana use, and environmental toxins." will actually be fixed
- ravenstine 6y ago
  Women already get to play with their hormones without a prescription, but for some reason we make it really difficult for men to safely adjust their hormone levels. There's a lot of misconceptions about testosterone and how it can be used to benefit lots of men. If you go into any doctor and they have tour testosterone tested, they probably won't give you TRT unless your T is below the low-bound of "normal", but being on the low-bound means you're not at your optimal. There's also lots of scare material about TRT out there for people who don't want to body build; supposedly you're guaranteed to have cardiovascular issues, shrunken testicles, 'roid rage, and so forth. If you keep your T at its optimal level but not going significantly past that, the chances of serious issues are minimal. TRT aside, young people need to get their vitamin D, get exercise, eat little to no refined sugar, filter their water, and be allowed to co-mingle; when males and females are separated for long periods of time, testosterone decreases even more.
  - mrweasel 6y ago
    > Women already get to play with their hormones without a prescription I don’t think that’s true. Even birthcontrol requires a prescription.
    - scohesc 6y ago
      In some places you can ask your pharmacist to write up a prescription for birth control without even consulting your doctor. I know this because I live somewhere where this is the case.
  - The_rationalist 6y ago
fjabre 6y ago
The ones staying inside all day playing Cyberpunk and not moving from the couch all day? Surprise. We've turned ourselves into actual couch potatoes. Wall-E was prophetic in this regard. I would love to see this on a chart next to video game and netflix original series releases.
- adkadskhj 6y ago
  Wall-E was made when obesity was already insanely out of control. It was a commentary on society, not a prediction.
- gameswithgo 6y ago
  physical activity was controlled for
  - adrr 6y ago
    Can you really control for that when our lifestyle has fundamentally changed over time? Washing dishes by hand is something I have stopped doing since 1990 as an example.
  - asdff 6y ago
    but not sleep
- deleted 6y ago
  [deleted]
- paxys 6y ago
  "The youth of today is lazy and stay indoors all day unlike our generation" – evergreen complaint documented going back at least 2000 years. Aristotle was ranting about "millennials" in 4 BC. https://www.bbc.com/worklife/article/20171003-proof-that-people-have-always-complained-about-young-adults https://www.bbc.com/worklife/article/20171003-proof-that-peo...
  - draw_down 6y ago
    Sure, nothing has ever changed. Anyone who says anything has changed is just Aristotle
deleted 6y ago
[deleted]
xwdv 6y ago
I’m sure this thought will be a downvote magnet but I wonder if low testosterone levels is somehow related to the “snowflakes” phenomenon in US culture.
- deleted 6y ago
  [deleted]
- multjoy 6y ago
  Except it isn’t actually a thing. The people who loudly proclaim ‘snowflake’ invariably have zero personal resilience themselves.
  - ketamine__ 6y ago
    Exactly. Constant complaining doesn't show much resilience.
  - xwdv 6y ago
    I don’t see how that’s dismissing my idea? Low testosterone all around it seems.
    - adkadskhj 6y ago
      S/He's dismissing the idea of snowflake culture, not the testosterone study.
- helen___keller 6y ago
  "snowflake" is used commonly as a pejorative without a clear definition in mind, much less a consistent application criteria. If you could specify in more detail what phenomena you think may be related to low testosterone, you're more likely to find better reception.
  - xwdv 6y ago
    Someone else can probably describe it better than me with concrete examples and comparing and contrasting different periods in history, I only have a feel for the zeitgeist.
helen___keller 6y ago
The study states the majority of the effect is for fairly predictable causes like age and obesity, but I found this interesting: > After controlling for confounders—including year of study, age, race, BMI, comorbidity status, alcohol and smoking use, and level of physical activity—total testosterone was lower among men in the later (2011-2016) versus earlier (1999-2000) cycles (P < 0.001) Excluding all those confounders, there's not much we're left with. Environmental toxins?
- admiralspoo 6y ago
  Why does it have to be toxins? What about diet?
  - gameswithgo 6y ago
    would need to be dietary changes that don't also change BMI, since that was controlled for.
    - godshatter 6y ago
      I wonder if soil depletion of minerals and vitamins due to over farming couldn't also be a suspect here. It's a problem I haven't heard much about lately.
    - NoPicklez 6y ago
      Which I think is a bit of a gaping hole. As a male who has been around 70kg for all of my adult life, I have consumed many different "diets". All from eating whole foods to eating more processed foods and easy packaged meals/junk food, all not impacting my BMI.
- waihtis 6y ago
  Plastics?
  - lom888 6y ago
    This is a common theory. https://www.npr.org/2011/03/02/134196209/study-most-plastics-leach-hormone-like-chemicals https://www.npr.org/2011/03/02/134196209/study-most-plastics...
tolbish 6y ago
More information on the effects of phytoestrogen (e.g. soy) from a study here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3074428/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3074428/
- second--shift 6y ago
  straight from the quoted article: > For a typical consumer, alarm over soy products is likely unnecessary
MAGZine 6y ago
I can't help but wonder if this has to do with an increasing pessimism in the future and higher rates of mental illness.
- redisman 6y ago
  Depression, lethargy, other mood issues are common for low testosterone. I’ve been thinking of getting tested myself
inglor_cz 6y ago
This seems to be a global phenomenon. https://rbej.biomedcentral.com/articles/10.1186/s12958-020-00575-2 https://rbej.biomedcentral.com/articles/10.1186/s12958-020-0... Possible toxicity of something that we deem safe could be an explanation. A side comment. I am 42. When I was younger, in the late 90s, getting into physical fight was much more common than today. These days even drunk young guys seem to be content with hurling a few insults. (For record, I am a peaceful person and the possibility of getting beaten up for no good reason was something I definitely did not look forward to during my old pub crawls.) I wonder if this is actually a manifestation of population-wide testosterone drop.
- fred_is_fred 6y ago
  Violent crime in the US has been dropping for some time now. Reduction of environmental lead (gas and paint) is one of the factors as well. https://www.medicaldaily.com/leaded-gasoline-linked-rise-and-fall-violent-crime-244173 https://www.medicaldaily.com/leaded-gasoline-linked-rise-and... Also I would guess that at 42 you are much less likely to be in a situation where a physical fight might start than you were in the 1990s - at bars at 2am for example. I know that I am.
  - mrec 6y ago
    Yes, this would be my first suspicion too, especially for a comparison with the 1990s. > For instance, the peak in leaded gasoline use in the late 1970's corresponds to a peak in aggravated assault rates in the late 1990's in urban areas across the United States. https://en.wikipedia.org/wiki/Lead_poisoning#Violence https://en.wikipedia.org/wiki/Lead_poisoning#Violence
    - flukus 6y ago
      I wonder if this could be the causal link between the two that has always been missing, lead -> higher testosterone -> more violence.
- f430 6y ago
  > getting into physical fight was much more common than today I distinctly remember the popularity of gang culture in North American west coast cities. Everybody were forming gangs based on ethnicity usually (but racial diversity isn't uncommon). This was the era of gangster rap, Tupac, Biggie Smalls, Ice Cube, DMX, Bone Thugs, Nas....all the classics...the lyrics are simply HARD compared to today.
klmadfejno 6y ago
Plastics and what not feel like easy targets, but I would bet this is primarily BMI. The paper seems to conclude that BMI is the big part. > Elevated BMI was associated with reduced total testosterone levels (P < .0001), with the mean BMI increasing from 25.83 in 1999-2000, to 27.96 in 2015-2016 (P = 0.0006). They do say: > Lokeshwar noted that even men with a normal BMI (18.5-24.9) had declining total testosterone levels (P < .05) during the same time frames. However the range of 18.5-24.9 is wider than the mean increase that they think is the most noteworthy independent variable. It's fully possible that within the BMI band of 18.5-24.9, average BMI nonetheless increased and is the primary driver. Note that the effect size over time is muuuuch more significant when not controlling for binned BMI. That doesn't mean whatever environmental shit you're not fond of is safe of course. Heck, in some roundabout way it may even be contributing to obesity, possibly even through other hormonal changes. Wouldn't be my first guess though.
- likpok 6y ago
  One other interesting factor: BMI is a rough measure with substantial room for error. Everyone likes to criticize BMI because a lean athlete can show up as "overweight" due to muscle, but the opposite is also true. If you have a lot less muscle then increased fat can show up as "normal". I would hazard a guess that there are a lot more people with less lean muscle tissue than the 1970s, so BMI can understate how fat people are.
  - watwut 6y ago
    BMI is great. But, not for individuals. If you average BMI, you get great cheap population measurw
- nxc18 6y ago
  Completely agree about BMI ranges potentially being too wide. I just checked Fitbit and was surprised to see I’m now in the “ideal” range. I have man boobs and a muffin top. While I’m rarely the fattest person around anymore, I’m very clearly still overweight. It’s rare enough to see men that aren’t visibly overweight that it feels like a real exception when I do. I suspect there are _lots_ of fat men with an “ideal” BMI 18.5-24.9.
davesque 6y ago
I see a lot of speculation here about something like an unknown toxin being the cause. Is it possible that societal and cultural trends are driving this change? In other words, the emotional quality of modern day life. Perhaps another explanation is simply just evolution. After all, what does physical prowess really get you nowadays compared with even 20 or 30 years before?
wassenaar10 6y ago
Microplastics in most water supplies, hormones in most meats, and the western diet in general being high in sugars and simple carbohydrates seem to me to be the most likely culprits. It's also possible that other sources of pollution, for example pesticides, pay a role in it but that's something I know less about. Good luck getting anything done about the ubiquity of endocrine disrupters in our food and water supply though. The lack of an acute effect and the difficulty in even assigning causality for something like this makes regulatory action pretty difficult.
- datavirtue 6y ago
  That's because you are fighting the people who pay for the elections. Outside of that, banning endocrine disrupters is trivial. See France.
dropbear__cute 6y ago
Young men have important things to do, apart from fighting for dominance.
totalZero 6y ago
Dr. Philip Zimbardo wrote a book called "Man, Interrupted" that addresses this topic to some degree. One factor that he mentioned was the advent of high-speed internet, supporting both video games (virtual achievement) and pornography (virtual gratification). AOL announced its plans for high-speed DSL internet in January of 1999 -- the same year as the beginning of the study period. https://webcache.googleusercontent.com/search?q=cache:wV1z7-ujzj4J:edition.cnn.com/TECH/computing/9901/15/aolspeed.idg/+&cd=3&hl=en&ct=clnk&gl=us https://webcache.googleusercontent.com/search?q=cache:wV1z7-...
dukeofdoom 6y ago
Men are becoming wimpier. I know my cousin growing up was afraid of dogs, heights, terrified of open water, and so on. He grew up with few friends, did not play any sports, and spent most days indoors on the computer, very over protective mother. Honestly, in previous times he would be ridiculed for being very wimpy and scared of the world. Very little social pressure now. You can just retreat into your man cave, battle station, or cacoon after coming home from a very safe office job. Masculinity is not just genetic. Just like muscles, it needs context for it to develop. Had he grown up in Sparta, same person, would be different.
- helen___keller 6y ago
  > Very little social pressure now. You can just retreat into your man cave, battle station, or cacoon after coming home from a very safe office job. Is there a reason to believe this kind of social pressure would actually affect your testosterone levels? Does being pressured into acting more manly actually change your hormone levels? Sounds dubious, unless we're going by second order effects (decreased obesity from doing "manly things", etc).
  - dukeofdoom 6y ago
    Well you answered your own question. You become by doing. If you don't train muscles they don't grow. If you're sedentary, and obese, knock on effect from doing that. Just think about it this way. If you got dropped off to live in the wilderness of Alaska. And I came back to visit you in a year. Do you think you would be more masculine. I bet so. All kinds of changes would need to be made by you and your body just to survive. From fitness level, to body fat percentage, and so on.
    - klmadfejno 6y ago
      I find this worldview really funny. How would you increase estrogen?
      - itsyaboi 6y ago
stonecraftwolf 6y ago
If due to environmental toxins (say, hormonally active “forever chemicals,” plastics, etc), my guess is you’d see the deleterious effects first in women. Women also make (and need) testosterone, just at much lower levels than men, so they have much less to lose. There’s research going back 30 years on the efficacy of low dose TRT in women to treat all kinds of things that tend to hit women in their late thirties on (when natural testosterone has been declining for 15-20 years); I’m on mobile now, but what I recall most from a review paper was the efficacy in treating fibromyalgia pain. The lack of continued research on this seems to be almost entirely due to social pressure. (People lose their minds when you talk about women and testosterone, or men and estrogen.) It’s hard not to wonder if environmental toxins affecting the testosterone levels of men are also contributing to the rise of health issues in women, especially autoimmune conditions, fibromyalgia/CFS, obesity, depression, etc. In other words, women might be the canaries in the coal mine for systemic problems arising from environmental endocrine disruptors.
- Damorian 6y ago
  Related, girls (women?) are starting their periods about 5 years sooner compared to 100 years ago: https://en.wikipedia.org/wiki/Menarche#Changes_in_time_of_average_age https://en.wikipedia.org/wiki/Menarche#Changes_in_time_of_av...
  - perardi 6y ago
    Per Wikipedia, and other sources I’ve read, it seems heavily correlated with BMI. Which…makes a naïve sort of evolutionary sense. You need some percentage of body fat for your body to kick into reproduction mode.
  - joncrane 6y ago
    This has to do more with better nutrition and comfort than anything else. While it's true that estrogen-like compounds may also have an effect, it takes calories to ovulate and to menstruate.
zug_zug 6y ago
Sure seem to be a lot of comments attributing this to changes in daily life that were controlled for. Not saying it's 100% chemical, but it's always good to educate oneself on the possibility https://en.wikipedia.org/wiki/Xenoestrogen https://en.wikipedia.org/wiki/Xenoestrogen
rm2040 6y ago
Mean total testosterone decreased from 1999-2000 (605.39 ng/dL), 2003-2004 (567.44 ng/dL), 2011-2012 (424.96 ng/dL), 2013-2014 (431.76 ng/dL), andd 2015-2016 (451.22 ng/dL; all P < .0001).
bzb6 6y ago
Giving a literal sense to the saying “back in my time, when men where men”
mjfl 6y ago
They say they controlled for BMI, but if the dependence on BMI is nonlinear (i.e. higher BMI reinforces it's own destructive effect on testosterone) then there will still be a residual effect after that control. I think this effect is entirely due to BMI.
richardARPANET 6y ago
This explains a lot.
- deleted 6y ago
  [deleted]
anovikov 6y ago
It may be just simply due to overall degradation of mankind due to lower child mortality. It doesn't come for free after all.
sergiotapia 6y ago
Don't let this be you or your sons. Be an example. 1. Lift 2. Eat right 3. Hydrate 4. No porn 5. Do masculine things - something involving your strength and hands
- gnulinux 6y ago
  Do we have any evidence this would make a difference to testosterone levels?
  - throwaway93832 6y ago
    weights definitely does acutely . https://www.youtube.com/watch?v=yoP6NCGb3oM https://www.youtube.com/watch?v=yoP6NCGb3oM
  - sergiotapia 6y ago
    We have evidence squats increase test
hristov 6y ago
Pollutants in the environment have also been increasing. The world seems about the same as it did in the 90's but the amount of microplastics, herbicides and pesticides in our water and our food has gone through the roof. I wonder if we can scientifically show that lax environmental laws and enforcement of said laws ensures that your son will become a wimp, will that make all the fat head right wingers start taking environmental protection seriously?
hyko 6y ago
The paper doesn’t show a steady decrease.
WalterBright 6y ago
I've also seen articles saying there's a similar declining level of physical strength among men (measured by grip strength). I wonder if sitting at home all day playing video games instead of being outside running around reduces T levels.
- Beaver117 6y ago
  How does being outside running around increase grip strength?
  - Jtsummers 6y ago
    "Running around" means several things, in context he probably means kids being outside playing. Like running around the neighborhood, climbing things, throwing things, etc. Not just being on their feet running.
    - WalterBright 6y ago
      Yup. When I was a kid there was nothing to do inside. We were outside most of the time, riding bikes, building forts, wriggling through the storm drains, built a gokart, biking everywhere, impromptu games with the neighborhood kids who were also outside, throwing rocks, climbing trees, all very ordinary stuff for the times. I even tried to build an airplane out of scrap lumber, much to my dad's great amusement. Using a hand saw would sure make my arm ache :-) There are a lot of kids in my neighborhood, but I never see them. They're inside presumably playing video games.
francisofascii 6y ago
There have been studies that indicate women on birth control prefer men with less masculine faces (presumably from lower testosterone). So with birth control around since the 1950's, perhaps there is a link.
ty1564 6y ago
I'm reminded of two facts from Matthew Walker's book Why We Sleep: * People 5-18 years old sleep ~2 hours less per night than they did 100 years ago. * U of Chicago study found that men who limited their sleep to 5 hours per night for a week experienced a drop in testosterone equivalent to 10-15 years of aging.
- sleepyshift 6y ago
  The lack of sleep on almost everything is horrifying. I recommend that book to everyone whenever the topic is discussed.
okprod 6y ago
That's because everyone is in front of screens these days, usually seeking attention.
o_p 6y ago
And that's a good thing!
- ginko 6y ago
  You jest (I assume), but it really is startling how this isn't treated like the health crisis it seems to be. I come from a country with compulsory military service and there's regular talk about the health of young conscripts declining over the years. The solution by the government? Reduce the requirements for fitness so they can get the necessary number of men (not women of course).
  - o_p 6y ago
    I'm not sure if HNers worry about this because actual health risks or because of some male pride, maybe Im ignoring health risks caused by low testosterone, but I feel is quite the opposite, women are generally healthier and live longer. If anything, low T will make you bald less, there are many unhealthy habits of the modern life, sedentarism and obesity, that have real negative impacts, its odd to me why we would specifically care about this
    - DC1350 6y ago
      It also makes you sad, have low energy, less drive to do anything, lower muscle mass, worse facial aesthetics, more feminine fat distribution, weaker sperm, and less bone growth through puberty. It is pretty much not a good thing for any reason.
      - EVa5I7bHFq9mnYK 6y ago
        I have zero T after being chemically castrated, feel no sadness at all. I would say life is better after no longer having an urge to chase a hole all the time.
        temptemptemp111 6y ago
        No surprise considering you're 100% a mouthpiece for mainstream propaganda on here. Now preaching on the virtues of being spayed. Perhaps this is the way things should be.
at_a_remove 6y ago
I know from testing that mine would be perfectly normal ... if I were in my eighties and had to use a walker to get around, according to my doctor. He hypothesized that I may never have had normal levels and I am inclined to agree. Unfortunately, treatment is complicated by a metabolic disorder I have, so I would have to find an aromatase inhibitor to suit as well as something to put a halt to 5-alpha-reductase. Admittedly, I find myself somewhat afraid of a variety of small factors. Certainly I would like to keep my hair, but more than that I am concerned that I simply wouldn't know how to deal with the drive (normally one would say "renewed" here but I have been take-it-or-leave-it about most things).
legerdemain 6y ago
Can we use testosterone to absorb excess CO2??
glitchc 6y ago
One contributing factor is human beings self-selecting for passivity. We lock violent people away, and that dramatically reduces their chances of procreation. Over time, the population is likely to become more passive. Also, comfort. Life in North America, even for the poor, is more comfortable than life elsewhere on the planet. Finally, the average human in modern societies is far more cerebral now, because society requires complex interactions to get even simple things done. Thinking about the number of steps required to obtain temporary shelter now (book a hotel or AirBnB) vs 10000 years in the past. Just speculation in all cases, no hard data to back any of it up.
- patentatt 6y ago
  The study is focused on the last couple of decades, doesn't it seem unlikely any evolutionary selective pressures are a cause in such a short and recent time span?
- zeku 6y ago
  If it's not happening in Europe then both of your points are destroyed, just a thought. Very comfortable place to be, most of Europe.
godmode2019 6y ago
My 2 cents is we are much more socialised with the internet. Kids spend less time outside more time knowing what the latest social pressure is. One slip up and you will be cancelled. Similar to taking a dog to doggy day care they are socialise not to be aggressive, from a young age around other dogs and small children.
- watwut 6y ago
  Kids playing outside typically means "group". They were attuned to social pressure.
normlEyezd 6y ago
A baboon group lost its alpha males to illness from spoiled food. Researchers noted the remaining group developed more affectionate, communal behaviors as a result. Perhaps our change in culture, teaching kids earlier to adopt a more thoughtful approach to interacting with others is creating less external stimulus. https://www.nytimes.com/2004/04/13/science/no-time-for-bullies-baboons-retool-their-culture.html https://www.nytimes.com/2004/04/13/science/no-time-for-bulli...
kulig 6y ago
Chronic sleep deprivation?
cashsterling 6y ago
Read up on estrogen mimics: https://www.uwec.edu/academics/college-arts-sciences/departments-programs/watershed-institute/explore-opportunities/pollution-tour/pollution-tour-guide/estrogen-estrogen-mimics/ https://www.uwec.edu/academics/college-arts-sciences/departm... https://en.wikipedia.org/wiki/Xenoestrogen https://en.wikipedia.org/wiki/Xenoestrogen I think low level chemical exposure to many of these chemicals is largely to blame.
vixen99 6y ago
It is also clear that sperm counts have declined very significantly in the past decades. Some estimates put it at nearly 60% in Western men. But similar reports can be found for China https://www.nature.com/articles/s41598-020-67707-x.pdf https://www.nature.com/articles/s41598-020-67707-x.pdf and Africa. http://www.bioline.org.br/pdf?hs17052 http://www.bioline.org.br/pdf?hs17052
ausbah 6y ago
would this have any relationship to declining sperm rates as well?
kizer 6y ago
26 and just was prescribed testosterone booster. Haven’t changed anything... it really came out of nowhere.
kizer 6y ago
Also, it’s less acceptable it seems for men to display aggression or engage in debauchery. Many men are meant to fight or compete.
- danbolt 6y ago
  How do you know what someone's meant to do?
__alias 6y ago
I'm 25. Had a test 6 months ago out of curiosity, results came back at under 150. Doctor told me it had to have been a dud and had another test which resulted in around 300. Results are still significantly below average but the Doctor advised I don't purse TRT or anything as I don't have any adverse symptoms. I eat healthy, work out fairly regularly and get a fair bit of sun. I often wonder how different my muscle density / focus / sex drive would be at average T levels.
- hippich 6y ago
  For what it is worth - I am in my 30s, but not really having a healthy lifestyle. Had test of about 250 (one of the labs I done in search of getting motivation back). Doc put me on trt. In 4 month we dialed it to about 900-1000 stable. Had no noticable improvements in any areas (except morning wood like I am teenager again). Later there were some side effects and I discontinued it. Again, no noticable differences. For what it is worth, it appears that my body seems to need just that much of test.
  - joncrane 6y ago
    Some people have more receptors and/or are more sensitive to certain things. Higher testosterone leads to more risk taking and other adverse behaviors, as well as increased blood pressure and, anecdotally, "increased aging." I believe it has something to do with collagen synthesis. You absolutely made the right decision to come off TRT.
    - im3w1l 6y ago
      Risk taking has pros and cons. I'm surpried to see it described as adverse behavior on HN of all places.
    - justinko 6y ago
      Increases protein synthesis. My blood pressure is incredible now post TRT.
  - deleted 6y ago
    [deleted]
mullingitover 6y ago
I would wager that over the past four decades there's a pretty tight correlation between sugar consumption, obesity, and reduced testosterone.
wonder_er 6y ago
I listened to a podcast episode recently - I don't really listen to much of the podcast, but I had a 12 hr drive, and have enjoyed occasional episodes in the past. The host is Eric Weinstein, who is himself a scientist and seems to be a rather sharp individual. https://theportal.wiki/wiki/19:_Bret_Weinstein_-_The_Prediction_and_the_DISC https://theportal.wiki/wiki/19:_Bret_Weinstein_-_The_Predict... It takes _a while_ to get going. Eventually, however, the host has his brother explain a convoluted story where, basically, his brother (an extremely competent researcher and scientist) discovered a genetic anomily in all the mice used in labratories around the world. Because the mice were bread with such a pressure on the population, the telemeres on their DNA were getting awkwardly long (or short? I don't remember) resulting in their cells being _unusually good at repairing themselves_ with a downside of under-reporting the incident-rate of cancer. The discovery got sniped from him, when he started reaching out from other prominent researchers, and eventually the discovery was buried. It seems plausible that he tripped across an extremely damaging fact, one that would have forced a broad re-evaluation of the risk of many substances and medications recognized as "safe" or "healthy". Stuff like this long-term testosterone decrease, if it's indeed a bad thing (it might not be!) could be a result of that kind of scientific burying. Anyway - it was an interesting story.
lmilcin 6y ago
I wonder to what extend this is due to parenting and the fact kids are not exposed to other kids their age without adult control anymore. Then when they grow up they get consumed with electronic devices and loose chances for actual physical contact with others typically necessary to test your position on a ladder.
29athrowaway 6y ago
Toxins in plastic lower testosterone. https://www.google.com/amp/s/www.nextavenue.org/how-chemicals-plastic-lower-testosterone/amp/ https://www.google.com/amp/s/www.nextavenue.org/how-chemical...
icare_1er 6y ago
This explains a lot politically.
williesleg 6y ago
Hey soyboy!
asdff 6y ago
People cite activity declining, but really we've been plenty sedentary for all those decades since we eliminated electric public transit in most American cities in the 1950s-60s. Some people walk 20 feet to their car, 200 feet to the elevator, 20 feet to the cubicle, then end the day back at home without scarcely moving 1000 feet by their own leg. That isn't new between 1999 and today. People spend all day inside watching TV or playing video games rather than playing outside, that too isn't new. If anything, more people are biking, hiking, and running outside than they were 20 years ago. Another potential factor that I think may be a culprit is sleep. Americans sleep less today than 20 years ago: https://www.cbsnews.com/news/americans-get-less-sleep-than-20-years-ago/ https://www.cbsnews.com/news/americans-get-less-sleep-than-2... https://www.npr.org/sections/health-shots/2019/10/28/773622789/working-americans-are-getting-less-sleep-especially-those-who-save-our-lives https://www.npr.org/sections/health-shots/2019/10/28/7736227... What is driving this? Well, it could be our addiction to staring at a phone screen for hours at a time in total silence, unmoving. It's probably a combination of things, like the fact that americans are working more hours than they were 10 years ago and now have to sacrifice a good nights sleep to get all their personal business done when they aren't working: https://www.businessinsider.com/american-work-habits-culture-change-2019-3 https://www.businessinsider.com/american-work-habits-culture...
- sebmellen 6y ago
  Agreed — I would bet a lack of sleep due to hyperconnectivity, social media, and heavily increased exposure to bright artificial light through smartphones and laptops is the culprit. The change brought on by this now ubiquitous feature of life may be easy to ignore while we’re in it, but teleport someone from the 90s to now and the first thing they’d notice is smartphones and laptops, not that people are fatter or less in shape.
- agumonkey 6y ago
  Fractionated walks like these are still very different from sustained 10-20 (or even 40min) walks.
Fnoord 6y ago
@dang, (2020)
PIKAL 6y ago
Over the past two years I have fallen down a medical rabbit hole that has revealed some really weird things to me. I don’t know how to explain it convincingly so I’ll just get it out: The reason why this is happening is also part of why autism is going up (even when controlled for broader diagnosis) and autoimmune complaints are going up, as well as many other things. It’s because we have systematically eliminated fat and red meat from our diets over the past half decade, and also because we dialed up on sugar. In a bizarre plot twist, it turns out that everything we think about diet is wrong and a diet of beef, beef tallow and salt not only doesn’t screw up your cholesterol, it fixes almost every medical problem that people have. Again, it’s too wild for me to convince anyone. It’s too crazy. If you don’t believe me then go see for yourself. Meatrx slash success stories.
- yawnxyz 6y ago
  this is global, but eating beef regularly isn't / has never been a global thing
  - PIKAL 6y ago
    It was all people ate for millions of years
- redisman 6y ago
  Extraordinary claims require.. one anecdote? Globally we eat more meat per person today than ever before. Only very few people have been on a high beef diet ever in this world
  - watwut 6y ago
    100% true. To be fair, we don't know 1887 testosteroms levels.
    - redisman 6y ago
      Based on Teddy Roosevelt I’m guessing about 10x what it is now
xivusr 6y ago
Obesity, legal marijuana, & free porn. Zero "proof".
kleer001 6y ago
Sure, but is this a good thing?
hayst4ck 6y ago
https://www.sciencedirect.com/science/article/abs/pii/0018506X89900421 https://www.sciencedirect.com/science/article/abs/pii/001850... https://www.sciencedirect.com/science/article/abs/pii/0018506X8090032X https://www.sciencedirect.com/science/article/abs/pii/001850... Studies show that winning/losing and status have effects on testosterone. I would hypothesize that with social media every individual is now capable of comparing their status to a much wider selection of people and find themselves lacking. "I am so far behind" is a common sentiment I've heard among peers, this seems pretty similar to a feeling of losing a race.
croissants 6y ago
This reminds me of an episode of This American Life from 2002. There was a segment about a guy who had extremely low testosterone: > He explains that life without testosterone is life without desire—desire for everything: food, conversation, even TV. And he says life without desire is unexpectedly pleasant. [1] https://www.thisamericanlife.org/220/testosterone https://www.thisamericanlife.org/220/testosterone
SMAAART 6y ago
Could it be that the high protein / low carb diet have something to do with it? My money is on this one. A few years ago I switched to a high-protein diet because I started lifting, slowly but steadily things "went south". At one point was pretty bad. Then I found 1 obscure study linking low carb diet to low testosterone, I switched to a more balanced mediterranean diet and things improved and then got better than ever before. I know this is heresy, but.. I am putting out there, you've heard it here first.
- al_chemist 6y ago
  I doubt that many young people do "high protein / low carb" diet. It's hard to avoid carbs by mistake, especially with young people food like fries, pizza and beer. "Low carb" diet does not lower your testosterone. "High protein" diet does [1], because proteins will bond with testosterone. Increased magnesium will prevent that [2]. "High fat / low carb" diet will increase your testosterone due to increased dietary fat consumption. [1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2129168/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2129168/ [2]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3958794/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3958794/
hellbanTHIS 6y ago
Nobody's mentioning lack of sleep, that's when your body makes testosterone.
spurgu 6y ago
This will get buried but I read an article somewhat recently about sperm count, which seems to be related: https://www.gq.com/story/sperm-count-zero https://www.gq.com/story/sperm-count-zero
Geminidog 6y ago
Is there a study of testosterone levels in women? Anecdotally it feels like it's rising.
max_entropy 6y ago
My one word explanation: safety.
blargmaster42_8 6y ago
Eat more Soy
disposablex 6y ago
The study basically said body mass projected the same results? I can't help but think that the typical foods we consume as an 'advanced' nation are ones of convience and ones that primarily are addictive and unhealthy; this has to be a significant contributing factor. Along with low activity, more cerebral work, vs physical labor has to be a play as well. Edit: they did mention that comorbidities, including diabetes were a contributing factor. Sugar is the root of all evil, and Americans for sure love their corn syrups... after all it is their cash crop. Oddly enough, recently there was the company Lipocine in the news that created a new drug that basically is designed to restore normal testosterone levels in men: TLANDO.
nikolay 6y ago
Lower physical activity in addition to aromatase activators and xenoestrogens from the environment?
jxramos 6y ago
> According to Lokeshwar, potential causes for these declines could be increased obesity/BMI, assay variations, diet/phytoestrogens, declined exercise and physical activity, fat percentage, marijuana use, and environmental toxins. --Marijuana use? Is that legitimate? Does THC do some kind of endocrine confusion in the body? How in the world would marijuana use relate to the testes? Is THC or some derivative differentially absorbed in the testes with some detrimental effect? What would the mechanism be here exactly?
- zapdrive 6y ago
  It's already known that marijuana use lowers your testosterone in the short term. Maybe it also has a long term effect.
  - jxramos 6y ago
    Through what mechanism though? Does it stop the production of testosterone itself or does it bind to and saturate testosterone in the blood stream and sort of take it out of solution to no longer be detectable in the blood.
r34 6y ago
Maybe food has sth to do with decrease of testosterone, but I think it's rather cultural issue. 1. Lifestyle. Less sport, more cars etc. 2. Politics. Testosterone behaviors are less and less rewarded (or even directly punished). Adaptive strategy is to produce it less.
gigatexal 6y ago
I’ve been meaning to talk to my doctor about what I think are my own low Testosterone levels. I know I should work out more but I wonder where it fell off. I’m only 34.
BlahGod420 6y ago
It's banana hammocks.
justinko 6y ago
I feel pretty incredible on TRT. I’m 36, and started summer of last year with levels in the low 500’s. I’ve done a ton of research to get properly dialed-in. It’s nice knowing that I’m now shielded from these external causes of low T.
datsun510 6y ago
Polyunsaturated fats should be considered a suspected causative agent. The average person is unaware that even resting body temperatures are on the decline.[1] It is clear we are in the middle of a metabolic crisis. To those in the comments pointing out the 1970s as the estimated time this must have started, you may be interested in knowing that that's when soybean oil took the food market by storm.[2] [1] (not the best but you can find corroborating reports) https://elifesciences.org/articles/49555 https://elifesciences.org/articles/49555 [2] (figure within scientific literature) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076650/figure/fig10/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076650/figure/...
matonias 6y ago
First thing that comes to mind: Porn. It makes men empty their testosteron much quicker then putting in work and chasing after women.
johny115 6y ago
no one suspects porn? or social media, phone use, youtube, etc.? I know that these are bit difficult to get significant hard evidence for, but at least anecdotally, isn't this kind of obvious to every man? Being social in a real world, going to gym, pursuing goals ... you can feel the differences mounting up on yourself pretty clearly. On the other hand, watching porn, and browsing datings apps or social media ... depression, anxiety and low confidence sets in slowly. Don't believe its chemical toxicity. The shared variable across the whole planet is internet, porn, social media and increased phone use. There was none of this available in the past, so you had to entertain yourself in different ways. Now there is a lure of just staying at home and comforting yourself with the modern technology. None of which supports testosterone production as behaviors as opposed just going outside and doing something.
demoneyes 6y ago
I won't point to studies but it has been acknowledged as a side effect of Covid-19. Low testosterone can also result from liver damage or other organ failure.
afpx 6y ago
Do enough look ups on Google Trends, and you'll see that the areas that surround the Mississippi river (and inflow rivers) are often correlated with all sorts of medical diseases searches. For example, here's one for testosterone: https://trends.google.com/trends/explore?date=all&geo=US&q=low%20testosterone%20men https://trends.google.com/trends/explore?date=all&geo=US&q=l...

515 points by rasengan 6y ago

thehappypm 6y ago

Yet another symptom of the obesity epidemic.

thatguy0900 6y ago
That's not all of it. "Lokeshwar noted that even men with a normal BMI (18.5-24.9) had declining total testosterone levels (P < .05) during the same time frames." lack of hard physical labor in general, or modern diets just being filled with hormones?
- nabergh 6y ago
  Isn't it a fair question to ask though whether the average BMI of those with a "normal BMI" (18.5-24.9) changed during the time frames of interest? And if it did, couldn't that still be a cause?
- rychco 6y ago
  Lack of hard physical labor, combined with increasing average caloric intake may contribute to lower average muscle mass & total testosterone while still maintaining a "normal" BMI. I don't have evidence to support this, but this is my guess for falling testosterone within the "normal" BMI range over time (in addition to the effect of environmental pollutants on hormones).
- likpok 6y ago
  The "real" measure of how fat you are is body-fat percentage, which can vary at a given BMI level. It's not hard to imagine that people have gotten fatter at the same BMI level, as well as people being at the higher end of the "normal" range.
netizen-9748 6y ago
My money is on the ubiquitous endocrine disruptors that have polluted our ecosystem
- mamon 6y ago
  Yeah, all that soy lattes start to add up :)
  - WalterSear 6y ago
    That's a myth from the 80s.
  - netizen-9748 6y ago
    Oh, I didn't realise soy was a pollutant. Interesting.
ravenstine 6y ago
It's not the only cause but, from my experience, it's a big one, no pun intended. I might have made different diet choices as a young man if I knew that body fat aromatizes testosterone into estrogen. This is the primary cause for most cases of gynecomastia, which is why it's rare to see a man with breasts who isn't also overweight to some extent. Obesity is effectively feminizing a large portion of men and lowering their sexual market value. Overall, I think obesity is making people less attracted to each other, which can partially explain the decline in the rate of reproduction.
- Coding_Cat 6y ago
  > which is why it's rare to see a man with breasts who isn't also overweight to some extent. While (assumedly) true, I feel the need to note that the reverse does not hold generally: 'man boobs' are purely fat in nearly all cases and will go away when someone loses weight. Gynecomastia is breast tissue and does not go away if you lose weight.
- fortran77 6y ago
  In my opinion, it's the biggest problem facing us. Even this COVID pandemic would have been much less expensive without an obese population, because our hospital capacity may not have been pushed to its limits. CDC says being obese triples the likelihood a person would need hospitalization: https://www.cdc.gov/obesity/data/obesity-and-covid-19.html https://www.cdc.gov/obesity/data/obesity-and-covid-19.html I don't see a solution. We're not going to be able to use the same techniques used to get people not to smoke to address the obesity problem.

kaesar14 6y ago

Chalking this up to declining physical activity amongst young U.S. men.

nomoreusernames 6y ago
it mentions that they controlled for that.
- cellis 6y ago
  how did they control for that?
  - ausbah 6y ago
    by adding it as a feature into whatever model they created likely
srmatto 6y ago
They said that they controlled for that in the study.

thatguy0900 6y ago

I wonder if hormones will ever become widely available for personal use, or if we will just accept a changing hormonal landscape for men and woman. I doubt any of the underlying causes of "obesity/BMI, assay variations, diet/phytoestrogens, declined exercise and physical activity, fat percentage, marijuana use, and environmental toxins." will actually be fixed

ravenstine 6y ago
Women already get to play with their hormones without a prescription, but for some reason we make it really difficult for men to safely adjust their hormone levels. There's a lot of misconceptions about testosterone and how it can be used to benefit lots of men. If you go into any doctor and they have tour testosterone tested, they probably won't give you TRT unless your T is below the low-bound of "normal", but being on the low-bound means you're not at your optimal. There's also lots of scare material about TRT out there for people who don't want to body build; supposedly you're guaranteed to have cardiovascular issues, shrunken testicles, 'roid rage, and so forth. If you keep your T at its optimal level but not going significantly past that, the chances of serious issues are minimal. TRT aside, young people need to get their vitamin D, get exercise, eat little to no refined sugar, filter their water, and be allowed to co-mingle; when males and females are separated for long periods of time, testosterone decreases even more.
- mrweasel 6y ago
  > Women already get to play with their hormones without a prescription I don’t think that’s true. Even birthcontrol requires a prescription.
  - scohesc 6y ago
    In some places you can ask your pharmacist to write up a prescription for birth control without even consulting your doctor. I know this because I live somewhere where this is the case.
- The_rationalist 6y ago

fjabre 6y ago

The ones staying inside all day playing Cyberpunk and not moving from the couch all day? Surprise. We've turned ourselves into actual couch potatoes. Wall-E was prophetic in this regard. I would love to see this on a chart next to video game and netflix original series releases.

adkadskhj 6y ago
Wall-E was made when obesity was already insanely out of control. It was a commentary on society, not a prediction.
gameswithgo 6y ago
physical activity was controlled for
- adrr 6y ago
  Can you really control for that when our lifestyle has fundamentally changed over time? Washing dishes by hand is something I have stopped doing since 1990 as an example.
- asdff 6y ago
  but not sleep
deleted 6y ago
[deleted]
paxys 6y ago
"The youth of today is lazy and stay indoors all day unlike our generation" – evergreen complaint documented going back at least 2000 years. Aristotle was ranting about "millennials" in 4 BC. https://www.bbc.com/worklife/article/20171003-proof-that-people-have-always-complained-about-young-adults https://www.bbc.com/worklife/article/20171003-proof-that-peo...
- draw_down 6y ago
  Sure, nothing has ever changed. Anyone who says anything has changed is just Aristotle

deleted 6y ago

[deleted]

xwdv 6y ago

I’m sure this thought will be a downvote magnet but I wonder if low testosterone levels is somehow related to the “snowflakes” phenomenon in US culture.

deleted 6y ago
[deleted]
multjoy 6y ago
Except it isn’t actually a thing. The people who loudly proclaim ‘snowflake’ invariably have zero personal resilience themselves.
- ketamine__ 6y ago
  Exactly. Constant complaining doesn't show much resilience.
- xwdv 6y ago
  I don’t see how that’s dismissing my idea? Low testosterone all around it seems.
  - adkadskhj 6y ago
    S/He's dismissing the idea of snowflake culture, not the testosterone study.
helen___keller 6y ago
"snowflake" is used commonly as a pejorative without a clear definition in mind, much less a consistent application criteria. If you could specify in more detail what phenomena you think may be related to low testosterone, you're more likely to find better reception.
- xwdv 6y ago
  Someone else can probably describe it better than me with concrete examples and comparing and contrasting different periods in history, I only have a feel for the zeitgeist.

helen___keller 6y ago

The study states the majority of the effect is for fairly predictable causes like age and obesity, but I found this interesting: > After controlling for confounders—including year of study, age, race, BMI, comorbidity status, alcohol and smoking use, and level of physical activity—total testosterone was lower among men in the later (2011-2016) versus earlier (1999-2000) cycles (P < 0.001) Excluding all those confounders, there's not much we're left with. Environmental toxins?

admiralspoo 6y ago
Why does it have to be toxins? What about diet?
- gameswithgo 6y ago
  would need to be dietary changes that don't also change BMI, since that was controlled for.
  - godshatter 6y ago
    I wonder if soil depletion of minerals and vitamins due to over farming couldn't also be a suspect here. It's a problem I haven't heard much about lately.
  - NoPicklez 6y ago
    Which I think is a bit of a gaping hole. As a male who has been around 70kg for all of my adult life, I have consumed many different "diets". All from eating whole foods to eating more processed foods and easy packaged meals/junk food, all not impacting my BMI.
waihtis 6y ago
Plastics?
- lom888 6y ago
  This is a common theory. https://www.npr.org/2011/03/02/134196209/study-most-plastics-leach-hormone-like-chemicals https://www.npr.org/2011/03/02/134196209/study-most-plastics...

tolbish 6y ago

More information on the effects of phytoestrogen (e.g. soy) from a study here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3074428/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3074428/

second--shift 6y ago
straight from the quoted article: > For a typical consumer, alarm over soy products is likely unnecessary

MAGZine 6y ago

I can't help but wonder if this has to do with an increasing pessimism in the future and higher rates of mental illness.

redisman 6y ago
Depression, lethargy, other mood issues are common for low testosterone. I’ve been thinking of getting tested myself

inglor_cz 6y ago

This seems to be a global phenomenon. https://rbej.biomedcentral.com/articles/10.1186/s12958-020-00575-2 https://rbej.biomedcentral.com/articles/10.1186/s12958-020-0... Possible toxicity of something that we deem safe could be an explanation. A side comment. I am 42. When I was younger, in the late 90s, getting into physical fight was much more common than today. These days even drunk young guys seem to be content with hurling a few insults. (For record, I am a peaceful person and the possibility of getting beaten up for no good reason was something I definitely did not look forward to during my old pub crawls.) I wonder if this is actually a manifestation of population-wide testosterone drop.

fred_is_fred 6y ago
Violent crime in the US has been dropping for some time now. Reduction of environmental lead (gas and paint) is one of the factors as well. https://www.medicaldaily.com/leaded-gasoline-linked-rise-and-fall-violent-crime-244173 https://www.medicaldaily.com/leaded-gasoline-linked-rise-and... Also I would guess that at 42 you are much less likely to be in a situation where a physical fight might start than you were in the 1990s - at bars at 2am for example. I know that I am.
- mrec 6y ago
  Yes, this would be my first suspicion too, especially for a comparison with the 1990s. > For instance, the peak in leaded gasoline use in the late 1970's corresponds to a peak in aggravated assault rates in the late 1990's in urban areas across the United States. https://en.wikipedia.org/wiki/Lead_poisoning#Violence https://en.wikipedia.org/wiki/Lead_poisoning#Violence
  - flukus 6y ago
    I wonder if this could be the causal link between the two that has always been missing, lead -> higher testosterone -> more violence.
f430 6y ago
> getting into physical fight was much more common than today I distinctly remember the popularity of gang culture in North American west coast cities. Everybody were forming gangs based on ethnicity usually (but racial diversity isn't uncommon). This was the era of gangster rap, Tupac, Biggie Smalls, Ice Cube, DMX, Bone Thugs, Nas....all the classics...the lyrics are simply HARD compared to today.

klmadfejno 6y ago

Plastics and what not feel like easy targets, but I would bet this is primarily BMI. The paper seems to conclude that BMI is the big part. > Elevated BMI was associated with reduced total testosterone levels (P < .0001), with the mean BMI increasing from 25.83 in 1999-2000, to 27.96 in 2015-2016 (P = 0.0006). They do say: > Lokeshwar noted that even men with a normal BMI (18.5-24.9) had declining total testosterone levels (P < .05) during the same time frames. However the range of 18.5-24.9 is wider than the mean increase that they think is the most noteworthy independent variable. It's fully possible that within the BMI band of 18.5-24.9, average BMI nonetheless increased and is the primary driver. Note that the effect size over time is muuuuch more significant when not controlling for binned BMI. That doesn't mean whatever environmental shit you're not fond of is safe of course. Heck, in some roundabout way it may even be contributing to obesity, possibly even through other hormonal changes. Wouldn't be my first guess though.

likpok 6y ago
One other interesting factor: BMI is a rough measure with substantial room for error. Everyone likes to criticize BMI because a lean athlete can show up as "overweight" due to muscle, but the opposite is also true. If you have a lot less muscle then increased fat can show up as "normal". I would hazard a guess that there are a lot more people with less lean muscle tissue than the 1970s, so BMI can understate how fat people are.
- watwut 6y ago
  BMI is great. But, not for individuals. If you average BMI, you get great cheap population measurw
nxc18 6y ago
Completely agree about BMI ranges potentially being too wide. I just checked Fitbit and was surprised to see I’m now in the “ideal” range. I have man boobs and a muffin top. While I’m rarely the fattest person around anymore, I’m very clearly still overweight. It’s rare enough to see men that aren’t visibly overweight that it feels like a real exception when I do. I suspect there are _lots_ of fat men with an “ideal” BMI 18.5-24.9.

davesque 6y ago

I see a lot of speculation here about something like an unknown toxin being the cause. Is it possible that societal and cultural trends are driving this change? In other words, the emotional quality of modern day life. Perhaps another explanation is simply just evolution. After all, what does physical prowess really get you nowadays compared with even 20 or 30 years before?

wassenaar10 6y ago

Microplastics in most water supplies, hormones in most meats, and the western diet in general being high in sugars and simple carbohydrates seem to me to be the most likely culprits. It's also possible that other sources of pollution, for example pesticides, pay a role in it but that's something I know less about. Good luck getting anything done about the ubiquity of endocrine disrupters in our food and water supply though. The lack of an acute effect and the difficulty in even assigning causality for something like this makes regulatory action pretty difficult.

datavirtue 6y ago
That's because you are fighting the people who pay for the elections. Outside of that, banning endocrine disrupters is trivial. See France.

dropbear__cute 6y ago

Young men have important things to do, apart from fighting for dominance.

totalZero 6y ago

Dr. Philip Zimbardo wrote a book called "Man, Interrupted" that addresses this topic to some degree. One factor that he mentioned was the advent of high-speed internet, supporting both video games (virtual achievement) and pornography (virtual gratification). AOL announced its plans for high-speed DSL internet in January of 1999 -- the same year as the beginning of the study period. https://webcache.googleusercontent.com/search?q=cache:wV1z7-ujzj4J:edition.cnn.com/TECH/computing/9901/15/aolspeed.idg/+&cd=3&hl=en&ct=clnk&gl=us https://webcache.googleusercontent.com/search?q=cache:wV1z7-...

dukeofdoom 6y ago

Men are becoming wimpier. I know my cousin growing up was afraid of dogs, heights, terrified of open water, and so on. He grew up with few friends, did not play any sports, and spent most days indoors on the computer, very over protective mother. Honestly, in previous times he would be ridiculed for being very wimpy and scared of the world. Very little social pressure now. You can just retreat into your man cave, battle station, or cacoon after coming home from a very safe office job. Masculinity is not just genetic. Just like muscles, it needs context for it to develop. Had he grown up in Sparta, same person, would be different.

helen___keller 6y ago
> Very little social pressure now. You can just retreat into your man cave, battle station, or cacoon after coming home from a very safe office job. Is there a reason to believe this kind of social pressure would actually affect your testosterone levels? Does being pressured into acting more manly actually change your hormone levels? Sounds dubious, unless we're going by second order effects (decreased obesity from doing "manly things", etc).
- dukeofdoom 6y ago
  Well you answered your own question. You become by doing. If you don't train muscles they don't grow. If you're sedentary, and obese, knock on effect from doing that. Just think about it this way. If you got dropped off to live in the wilderness of Alaska. And I came back to visit you in a year. Do you think you would be more masculine. I bet so. All kinds of changes would need to be made by you and your body just to survive. From fitness level, to body fat percentage, and so on.
  - klmadfejno 6y ago
    I find this worldview really funny. How would you increase estrogen?
    - itsyaboi 6y ago

stonecraftwolf 6y ago

If due to environmental toxins (say, hormonally active “forever chemicals,” plastics, etc), my guess is you’d see the deleterious effects first in women. Women also make (and need) testosterone, just at much lower levels than men, so they have much less to lose. There’s research going back 30 years on the efficacy of low dose TRT in women to treat all kinds of things that tend to hit women in their late thirties on (when natural testosterone has been declining for 15-20 years); I’m on mobile now, but what I recall most from a review paper was the efficacy in treating fibromyalgia pain. The lack of continued research on this seems to be almost entirely due to social pressure. (People lose their minds when you talk about women and testosterone, or men and estrogen.) It’s hard not to wonder if environmental toxins affecting the testosterone levels of men are also contributing to the rise of health issues in women, especially autoimmune conditions, fibromyalgia/CFS, obesity, depression, etc. In other words, women might be the canaries in the coal mine for systemic problems arising from environmental endocrine disruptors.

Damorian 6y ago
Related, girls (women?) are starting their periods about 5 years sooner compared to 100 years ago: https://en.wikipedia.org/wiki/Menarche#Changes_in_time_of_average_age https://en.wikipedia.org/wiki/Menarche#Changes_in_time_of_av...
- perardi 6y ago
  Per Wikipedia, and other sources I’ve read, it seems heavily correlated with BMI. Which…makes a naïve sort of evolutionary sense. You need some percentage of body fat for your body to kick into reproduction mode.
- joncrane 6y ago
  This has to do more with better nutrition and comfort than anything else. While it's true that estrogen-like compounds may also have an effect, it takes calories to ovulate and to menstruate.

zug_zug 6y ago

Sure seem to be a lot of comments attributing this to changes in daily life that were controlled for. Not saying it's 100% chemical, but it's always good to educate oneself on the possibility https://en.wikipedia.org/wiki/Xenoestrogen https://en.wikipedia.org/wiki/Xenoestrogen

rm2040 6y ago

Mean total testosterone decreased from 1999-2000 (605.39 ng/dL), 2003-2004 (567.44 ng/dL), 2011-2012 (424.96 ng/dL), 2013-2014 (431.76 ng/dL), andd 2015-2016 (451.22 ng/dL; all P < .0001).

bzb6 6y ago

Giving a literal sense to the saying “back in my time, when men where men”

mjfl 6y ago

They say they controlled for BMI, but if the dependence on BMI is nonlinear (i.e. higher BMI reinforces it's own destructive effect on testosterone) then there will still be a residual effect after that control. I think this effect is entirely due to BMI.

richardARPANET 6y ago

This explains a lot.

deleted 6y ago
[deleted]

anovikov 6y ago

It may be just simply due to overall degradation of mankind due to lower child mortality. It doesn't come for free after all.

sergiotapia 6y ago

Don't let this be you or your sons. Be an example. 1. Lift 2. Eat right 3. Hydrate 4. No porn 5. Do masculine things - something involving your strength and hands

gnulinux 6y ago
Do we have any evidence this would make a difference to testosterone levels?
- throwaway93832 6y ago
  weights definitely does acutely . https://www.youtube.com/watch?v=yoP6NCGb3oM https://www.youtube.com/watch?v=yoP6NCGb3oM
- sergiotapia 6y ago
  We have evidence squats increase test

hristov 6y ago

Pollutants in the environment have also been increasing. The world seems about the same as it did in the 90's but the amount of microplastics, herbicides and pesticides in our water and our food has gone through the roof. I wonder if we can scientifically show that lax environmental laws and enforcement of said laws ensures that your son will become a wimp, will that make all the fat head right wingers start taking environmental protection seriously?

hyko 6y ago

The paper doesn’t show a steady decrease.

WalterBright 6y ago

I've also seen articles saying there's a similar declining level of physical strength among men (measured by grip strength). I wonder if sitting at home all day playing video games instead of being outside running around reduces T levels.

Beaver117 6y ago
How does being outside running around increase grip strength?
- Jtsummers 6y ago
  "Running around" means several things, in context he probably means kids being outside playing. Like running around the neighborhood, climbing things, throwing things, etc. Not just being on their feet running.
  - WalterBright 6y ago
    Yup. When I was a kid there was nothing to do inside. We were outside most of the time, riding bikes, building forts, wriggling through the storm drains, built a gokart, biking everywhere, impromptu games with the neighborhood kids who were also outside, throwing rocks, climbing trees, all very ordinary stuff for the times. I even tried to build an airplane out of scrap lumber, much to my dad's great amusement. Using a hand saw would sure make my arm ache :-) There are a lot of kids in my neighborhood, but I never see them. They're inside presumably playing video games.

francisofascii 6y ago

There have been studies that indicate women on birth control prefer men with less masculine faces (presumably from lower testosterone). So with birth control around since the 1950's, perhaps there is a link.

ty1564 6y ago

I'm reminded of two facts from Matthew Walker's book Why We Sleep: * People 5-18 years old sleep ~2 hours less per night than they did 100 years ago. * U of Chicago study found that men who limited their sleep to 5 hours per night for a week experienced a drop in testosterone equivalent to 10-15 years of aging.

sleepyshift 6y ago
The lack of sleep on almost everything is horrifying. I recommend that book to everyone whenever the topic is discussed.

okprod 6y ago

That's because everyone is in front of screens these days, usually seeking attention.

o_p 6y ago

And that's a good thing!

ginko 6y ago
You jest (I assume), but it really is startling how this isn't treated like the health crisis it seems to be. I come from a country with compulsory military service and there's regular talk about the health of young conscripts declining over the years. The solution by the government? Reduce the requirements for fitness so they can get the necessary number of men (not women of course).
- o_p 6y ago
  I'm not sure if HNers worry about this because actual health risks or because of some male pride, maybe Im ignoring health risks caused by low testosterone, but I feel is quite the opposite, women are generally healthier and live longer. If anything, low T will make you bald less, there are many unhealthy habits of the modern life, sedentarism and obesity, that have real negative impacts, its odd to me why we would specifically care about this
  - DC1350 6y ago
    It also makes you sad, have low energy, less drive to do anything, lower muscle mass, worse facial aesthetics, more feminine fat distribution, weaker sperm, and less bone growth through puberty. It is pretty much not a good thing for any reason.
    - EVa5I7bHFq9mnYK 6y ago
      I have zero T after being chemically castrated, feel no sadness at all. I would say life is better after no longer having an urge to chase a hole all the time.
      - temptemptemp111 6y ago
        No surprise considering you're 100% a mouthpiece for mainstream propaganda on here. Now preaching on the virtues of being spayed. Perhaps this is the way things should be.

at_a_remove 6y ago

I know from testing that mine would be perfectly normal ... if I were in my eighties and had to use a walker to get around, according to my doctor. He hypothesized that I may never have had normal levels and I am inclined to agree. Unfortunately, treatment is complicated by a metabolic disorder I have, so I would have to find an aromatase inhibitor to suit as well as something to put a halt to 5-alpha-reductase. Admittedly, I find myself somewhat afraid of a variety of small factors. Certainly I would like to keep my hair, but more than that I am concerned that I simply wouldn't know how to deal with the drive (normally one would say "renewed" here but I have been take-it-or-leave-it about most things).

legerdemain 6y ago

Can we use testosterone to absorb excess CO2??

glitchc 6y ago

One contributing factor is human beings self-selecting for passivity. We lock violent people away, and that dramatically reduces their chances of procreation. Over time, the population is likely to become more passive. Also, comfort. Life in North America, even for the poor, is more comfortable than life elsewhere on the planet. Finally, the average human in modern societies is far more cerebral now, because society requires complex interactions to get even simple things done. Thinking about the number of steps required to obtain temporary shelter now (book a hotel or AirBnB) vs 10000 years in the past. Just speculation in all cases, no hard data to back any of it up.

patentatt 6y ago
The study is focused on the last couple of decades, doesn't it seem unlikely any evolutionary selective pressures are a cause in such a short and recent time span?
zeku 6y ago
If it's not happening in Europe then both of your points are destroyed, just a thought. Very comfortable place to be, most of Europe.

godmode2019 6y ago

My 2 cents is we are much more socialised with the internet. Kids spend less time outside more time knowing what the latest social pressure is. One slip up and you will be cancelled. Similar to taking a dog to doggy day care they are socialise not to be aggressive, from a young age around other dogs and small children.

watwut 6y ago
Kids playing outside typically means "group". They were attuned to social pressure.

normlEyezd 6y ago

A baboon group lost its alpha males to illness from spoiled food. Researchers noted the remaining group developed more affectionate, communal behaviors as a result. Perhaps our change in culture, teaching kids earlier to adopt a more thoughtful approach to interacting with others is creating less external stimulus. https://www.nytimes.com/2004/04/13/science/no-time-for-bullies-baboons-retool-their-culture.html https://www.nytimes.com/2004/04/13/science/no-time-for-bulli...

kulig 6y ago

Chronic sleep deprivation?

cashsterling 6y ago

Read up on estrogen mimics: https://www.uwec.edu/academics/college-arts-sciences/departments-programs/watershed-institute/explore-opportunities/pollution-tour/pollution-tour-guide/estrogen-estrogen-mimics/ https://www.uwec.edu/academics/college-arts-sciences/departm... https://en.wikipedia.org/wiki/Xenoestrogen https://en.wikipedia.org/wiki/Xenoestrogen I think low level chemical exposure to many of these chemicals is largely to blame.

vixen99 6y ago

It is also clear that sperm counts have declined very significantly in the past decades. Some estimates put it at nearly 60% in Western men. But similar reports can be found for China https://www.nature.com/articles/s41598-020-67707-x.pdf https://www.nature.com/articles/s41598-020-67707-x.pdf and Africa. http://www.bioline.org.br/pdf?hs17052 http://www.bioline.org.br/pdf?hs17052

ausbah 6y ago

would this have any relationship to declining sperm rates as well?

kizer 6y ago

26 and just was prescribed testosterone booster. Haven’t changed anything... it really came out of nowhere.

kizer 6y ago

Also, it’s less acceptable it seems for men to display aggression or engage in debauchery. Many men are meant to fight or compete.

danbolt 6y ago
How do you know what someone's meant to do?

__alias 6y ago

I'm 25. Had a test 6 months ago out of curiosity, results came back at under 150. Doctor told me it had to have been a dud and had another test which resulted in around 300. Results are still significantly below average but the Doctor advised I don't purse TRT or anything as I don't have any adverse symptoms. I eat healthy, work out fairly regularly and get a fair bit of sun. I often wonder how different my muscle density / focus / sex drive would be at average T levels.

hippich 6y ago
For what it is worth - I am in my 30s, but not really having a healthy lifestyle. Had test of about 250 (one of the labs I done in search of getting motivation back). Doc put me on trt. In 4 month we dialed it to about 900-1000 stable. Had no noticable improvements in any areas (except morning wood like I am teenager again). Later there were some side effects and I discontinued it. Again, no noticable differences. For what it is worth, it appears that my body seems to need just that much of test.
- joncrane 6y ago
  Some people have more receptors and/or are more sensitive to certain things. Higher testosterone leads to more risk taking and other adverse behaviors, as well as increased blood pressure and, anecdotally, "increased aging." I believe it has something to do with collagen synthesis. You absolutely made the right decision to come off TRT.
  - im3w1l 6y ago
    Risk taking has pros and cons. I'm surpried to see it described as adverse behavior on HN of all places.
  - justinko 6y ago
    Increases protein synthesis. My blood pressure is incredible now post TRT.
- deleted 6y ago
  [deleted]

mullingitover 6y ago

I would wager that over the past four decades there's a pretty tight correlation between sugar consumption, obesity, and reduced testosterone.

wonder_er 6y ago

I listened to a podcast episode recently - I don't really listen to much of the podcast, but I had a 12 hr drive, and have enjoyed occasional episodes in the past. The host is Eric Weinstein, who is himself a scientist and seems to be a rather sharp individual. https://theportal.wiki/wiki/19:_Bret_Weinstein_-_The_Prediction_and_the_DISC https://theportal.wiki/wiki/19:_Bret_Weinstein_-_The_Predict... It takes _a while_ to get going. Eventually, however, the host has his brother explain a convoluted story where, basically, his brother (an extremely competent researcher and scientist) discovered a genetic anomily in all the mice used in labratories around the world. Because the mice were bread with such a pressure on the population, the telemeres on their DNA were getting awkwardly long (or short? I don't remember) resulting in their cells being _unusually good at repairing themselves_ with a downside of under-reporting the incident-rate of cancer. The discovery got sniped from him, when he started reaching out from other prominent researchers, and eventually the discovery was buried. It seems plausible that he tripped across an extremely damaging fact, one that would have forced a broad re-evaluation of the risk of many substances and medications recognized as "safe" or "healthy". Stuff like this long-term testosterone decrease, if it's indeed a bad thing (it might not be!) could be a result of that kind of scientific burying. Anyway - it was an interesting story.

lmilcin 6y ago

I wonder to what extend this is due to parenting and the fact kids are not exposed to other kids their age without adult control anymore. Then when they grow up they get consumed with electronic devices and loose chances for actual physical contact with others typically necessary to test your position on a ladder.

29athrowaway 6y ago

Toxins in plastic lower testosterone. https://www.google.com/amp/s/www.nextavenue.org/how-chemicals-plastic-lower-testosterone/amp/ https://www.google.com/amp/s/www.nextavenue.org/how-chemical...

icare_1er 6y ago

This explains a lot politically.

williesleg 6y ago

Hey soyboy!

asdff 6y ago

People cite activity declining, but really we've been plenty sedentary for all those decades since we eliminated electric public transit in most American cities in the 1950s-60s. Some people walk 20 feet to their car, 200 feet to the elevator, 20 feet to the cubicle, then end the day back at home without scarcely moving 1000 feet by their own leg. That isn't new between 1999 and today. People spend all day inside watching TV or playing video games rather than playing outside, that too isn't new. If anything, more people are biking, hiking, and running outside than they were 20 years ago. Another potential factor that I think may be a culprit is sleep. Americans sleep less today than 20 years ago: https://www.cbsnews.com/news/americans-get-less-sleep-than-20-years-ago/ https://www.cbsnews.com/news/americans-get-less-sleep-than-2... https://www.npr.org/sections/health-shots/2019/10/28/773622789/working-americans-are-getting-less-sleep-especially-those-who-save-our-lives https://www.npr.org/sections/health-shots/2019/10/28/7736227... What is driving this? Well, it could be our addiction to staring at a phone screen for hours at a time in total silence, unmoving. It's probably a combination of things, like the fact that americans are working more hours than they were 10 years ago and now have to sacrifice a good nights sleep to get all their personal business done when they aren't working: https://www.businessinsider.com/american-work-habits-culture-change-2019-3 https://www.businessinsider.com/american-work-habits-culture...

sebmellen 6y ago
Agreed — I would bet a lack of sleep due to hyperconnectivity, social media, and heavily increased exposure to bright artificial light through smartphones and laptops is the culprit. The change brought on by this now ubiquitous feature of life may be easy to ignore while we’re in it, but teleport someone from the 90s to now and the first thing they’d notice is smartphones and laptops, not that people are fatter or less in shape.
agumonkey 6y ago
Fractionated walks like these are still very different from sustained 10-20 (or even 40min) walks.

Fnoord 6y ago

@dang, (2020)

PIKAL 6y ago

Over the past two years I have fallen down a medical rabbit hole that has revealed some really weird things to me. I don’t know how to explain it convincingly so I’ll just get it out: The reason why this is happening is also part of why autism is going up (even when controlled for broader diagnosis) and autoimmune complaints are going up, as well as many other things. It’s because we have systematically eliminated fat and red meat from our diets over the past half decade, and also because we dialed up on sugar. In a bizarre plot twist, it turns out that everything we think about diet is wrong and a diet of beef, beef tallow and salt not only doesn’t screw up your cholesterol, it fixes almost every medical problem that people have. Again, it’s too wild for me to convince anyone. It’s too crazy. If you don’t believe me then go see for yourself. Meatrx slash success stories.

yawnxyz 6y ago
this is global, but eating beef regularly isn't / has never been a global thing
- PIKAL 6y ago
  It was all people ate for millions of years
redisman 6y ago
Extraordinary claims require.. one anecdote? Globally we eat more meat per person today than ever before. Only very few people have been on a high beef diet ever in this world
- watwut 6y ago
  100% true. To be fair, we don't know 1887 testosteroms levels.
  - redisman 6y ago
    Based on Teddy Roosevelt I’m guessing about 10x what it is now

xivusr 6y ago

Obesity, legal marijuana, & free porn. Zero "proof".

kleer001 6y ago

Sure, but is this a good thing?

hayst4ck 6y ago

https://www.sciencedirect.com/science/article/abs/pii/0018506X89900421 https://www.sciencedirect.com/science/article/abs/pii/001850... https://www.sciencedirect.com/science/article/abs/pii/0018506X8090032X https://www.sciencedirect.com/science/article/abs/pii/001850... Studies show that winning/losing and status have effects on testosterone. I would hypothesize that with social media every individual is now capable of comparing their status to a much wider selection of people and find themselves lacking. "I am so far behind" is a common sentiment I've heard among peers, this seems pretty similar to a feeling of losing a race.

croissants 6y ago

This reminds me of an episode of This American Life from 2002. There was a segment about a guy who had extremely low testosterone: > He explains that life without testosterone is life without desire—desire for everything: food, conversation, even TV. And he says life without desire is unexpectedly pleasant. [1] https://www.thisamericanlife.org/220/testosterone https://www.thisamericanlife.org/220/testosterone

SMAAART 6y ago

Could it be that the high protein / low carb diet have something to do with it? My money is on this one. A few years ago I switched to a high-protein diet because I started lifting, slowly but steadily things "went south". At one point was pretty bad. Then I found 1 obscure study linking low carb diet to low testosterone, I switched to a more balanced mediterranean diet and things improved and then got better than ever before. I know this is heresy, but.. I am putting out there, you've heard it here first.

al_chemist 6y ago
I doubt that many young people do "high protein / low carb" diet. It's hard to avoid carbs by mistake, especially with young people food like fries, pizza and beer. "Low carb" diet does not lower your testosterone. "High protein" diet does [1], because proteins will bond with testosterone. Increased magnesium will prevent that [2]. "High fat / low carb" diet will increase your testosterone due to increased dietary fat consumption. [1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2129168/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2129168/ [2]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3958794/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3958794/

hellbanTHIS 6y ago

Nobody's mentioning lack of sleep, that's when your body makes testosterone.

spurgu 6y ago

This will get buried but I read an article somewhat recently about sperm count, which seems to be related: https://www.gq.com/story/sperm-count-zero https://www.gq.com/story/sperm-count-zero

Geminidog 6y ago

Is there a study of testosterone levels in women? Anecdotally it feels like it's rising.

max_entropy 6y ago

My one word explanation: safety.

blargmaster42_8 6y ago

Eat more Soy

disposablex 6y ago

The study basically said body mass projected the same results? I can't help but think that the typical foods we consume as an 'advanced' nation are ones of convience and ones that primarily are addictive and unhealthy; this has to be a significant contributing factor. Along with low activity, more cerebral work, vs physical labor has to be a play as well. Edit: they did mention that comorbidities, including diabetes were a contributing factor. Sugar is the root of all evil, and Americans for sure love their corn syrups... after all it is their cash crop. Oddly enough, recently there was the company Lipocine in the news that created a new drug that basically is designed to restore normal testosterone levels in men: TLANDO.

nikolay 6y ago

Lower physical activity in addition to aromatase activators and xenoestrogens from the environment?

jxramos 6y ago

> According to Lokeshwar, potential causes for these declines could be increased obesity/BMI, assay variations, diet/phytoestrogens, declined exercise and physical activity, fat percentage, marijuana use, and environmental toxins. --Marijuana use? Is that legitimate? Does THC do some kind of endocrine confusion in the body? How in the world would marijuana use relate to the testes? Is THC or some derivative differentially absorbed in the testes with some detrimental effect? What would the mechanism be here exactly?

zapdrive 6y ago
It's already known that marijuana use lowers your testosterone in the short term. Maybe it also has a long term effect.
- jxramos 6y ago
  Through what mechanism though? Does it stop the production of testosterone itself or does it bind to and saturate testosterone in the blood stream and sort of take it out of solution to no longer be detectable in the blood.

r34 6y ago

Maybe food has sth to do with decrease of testosterone, but I think it's rather cultural issue. 1. Lifestyle. Less sport, more cars etc. 2. Politics. Testosterone behaviors are less and less rewarded (or even directly punished). Adaptive strategy is to produce it less.

gigatexal 6y ago

I’ve been meaning to talk to my doctor about what I think are my own low Testosterone levels. I know I should work out more but I wonder where it fell off. I’m only 34.

BlahGod420 6y ago

It's banana hammocks.

justinko 6y ago

I feel pretty incredible on TRT. I’m 36, and started summer of last year with levels in the low 500’s. I’ve done a ton of research to get properly dialed-in. It’s nice knowing that I’m now shielded from these external causes of low T.

datsun510 6y ago

Polyunsaturated fats should be considered a suspected causative agent. The average person is unaware that even resting body temperatures are on the decline.[1] It is clear we are in the middle of a metabolic crisis. To those in the comments pointing out the 1970s as the estimated time this must have started, you may be interested in knowing that that's when soybean oil took the food market by storm.[2] [1] (not the best but you can find corroborating reports) https://elifesciences.org/articles/49555 https://elifesciences.org/articles/49555 [2] (figure within scientific literature) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076650/figure/fig10/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076650/figure/...

matonias 6y ago

First thing that comes to mind: Porn. It makes men empty their testosteron much quicker then putting in work and chasing after women.

johny115 6y ago

no one suspects porn? or social media, phone use, youtube, etc.? I know that these are bit difficult to get significant hard evidence for, but at least anecdotally, isn't this kind of obvious to every man? Being social in a real world, going to gym, pursuing goals ... you can feel the differences mounting up on yourself pretty clearly. On the other hand, watching porn, and browsing datings apps or social media ... depression, anxiety and low confidence sets in slowly. Don't believe its chemical toxicity. The shared variable across the whole planet is internet, porn, social media and increased phone use. There was none of this available in the past, so you had to entertain yourself in different ways. Now there is a lure of just staying at home and comforting yourself with the modern technology. None of which supports testosterone production as behaviors as opposed just going outside and doing something.

demoneyes 6y ago

I won't point to studies but it has been acknowledged as a side effect of Covid-19. Low testosterone can also result from liver damage or other organ failure.

afpx 6y ago

Do enough look ups on Google Trends, and you'll see that the areas that surround the Mississippi river (and inflow rivers) are often correlated with all sorts of medical diseases searches. For example, here's one for testosterone: https://trends.google.com/trends/explore?date=all&geo=US&q=low%20testosterone%20men https://trends.google.com/trends/explore?date=all&geo=US&q=l...