17 ms·

Continuous Glucose Monitoring

116 points by zdw 1y ago

leakycap 1y ago
The author's mention of the Hawthorn Effect fascinated me; I hadn't considered that with devices your care team can monitor. It will change a lot of lives when some device that doesn't draw blood can continuously monitor glucose, like a smartwatch.
- privatelypublic 1y ago
  Pretty sure optical glucose is already a thing- it's just not very accurate yet.
  - nmehner 1y ago
    https://www.fda.gov/medical-devices/safety-communications/do-not-use-smartwatches-or-smart-rings-measure-blood-glucose-levels-fda-safety-communication https://www.fda.gov/medical-devices/safety-communications/do... Existing smart watches that claim to do this are basically garbage. Just use a random number generator instead. Apple and Samsung are supposedly working on it: https://www.forbes.com/sites/davidphelan/2025/01/26/samsung-reveals-game-changer-blood-glucose-monitoring-to-outdo-apple-watch/ https://www.forbes.com/sites/davidphelan/2025/01/26/samsung-... But it seems to be hard and from what I have seen the new Galaxy Watch 8 won't have this feature.
    - leakycap 1y ago
      Great resources. It seems we'll see BP monitoring integrated in a mainstream base smartwatch before we'll get optical glucose monitoring.
    - privatelypublic 1y ago
      Smartphones are notorious for not delivering- heck, my fitbit won't even give me an actual wrist temp value. Theres optical ones that can be built in a lab and require profiling to an individual. The most accurate ones are still invasive- just not consumable fungus extract based. Maybe some biomedical company makes a reference design.
  - leakycap 1y ago
    I have used my phone camera to determine blood pressure, but I have yet to see a common consumer device with optical glucose monitoring. I'm suggesting that it will change the world when it is an integrated part of something many/most of us buy and would eventually upgrade to.
    - ASalazarMX 1y ago
      > I have used my phone camera to determine blood pressure You mean heart rate? they cleverly work by flooding your skin with the flash LED, and looking for small differences indicative of a heartbeat. Blood pressure is not something you can image with a consumer camera.
      - privatelypublic 1y ago
        Camera? Yes. Normal illumination? No.
- shreezus 1y ago
  I believe we will see integrated optical glucose sensors in a popular consumer wearable fairly soon. I don't think they'll be as accurate as blood sensors, however they will be a game-changer for many people (pre-diabetics, or gestational diabetes etc).
- sdpy 1y ago
  That would be a game-changer for so many people. We're already getting close, though. Those CGMs like Dexcom don't actually test blood; they check interstitial fluid. There's a 5-15 minute delay, but still way better than finger pricks all day. Non-invasive monitoring is still tricky. There’ve been some interesting attempts—like GlucoWatch back in the early 2000s, which used mild electrical currents, but caused skin irritation and never really caught on. Others have tried optical monitoring, radio waves, ultrasound, and even heat-based sensors. Feels like we’re getting closer, just not quite there yet.
- hammyhavoc 1y ago
  GlucoWear is awaiting CE mark currently.
bix6 1y ago
I believe these cheaper devices are not very accurate ie accuracy range of 20% which is a fairly wide window. I’ve also heard there are many things that can impact your glucose even with the same meal like time of day, exercise, stress, sleep, etc. So if you actually want to find the patterns you’d need the expensive CGM over many months.
- loremm 1y ago
  Is that true? I have no perspective but it's relied on by diabetics and if since they can't regulate it themselves, if the readings are off and they gave themselves insulin, they would know it is wrong. Maybe the OTC ones is different than the diabetic one but I didn't think so
  - privatelypublic 1y ago
    They're not any different. CGM's have issues- sometimes need to be calibrated against a finger stick (officially, they always need to be) In the end though- it's still a bit of fungal extract painted onto an electrode, and an ADC that reads the value every so often. Like any other glucose monitor.
    - deleted 1y ago
      [deleted]
  - djur 1y ago
    Stelo is basically just a consumer packaged version of the Dexcom G6, and in both cases they warn you to use a finger stick to verify unexpected readings. But finger sticks can be really inaccurate, too. For many diabetics it's not a life-or-death matter (only 1 in 4 type 2 patients end up using insulin), and the important thing is the trend over time. I've personally found my CGM to be really useful in understanding the effect of diet, sleep, stress, etc. on my blood glucose, like the OP says, but you definitely get some weird readings sometimes. Yesterday a new unit told me that my blood glucose dropped below 70 for 2 hours. It definitely didn't! After a while it got itself straightened out in time to scold me for eating some corn chips.
guiambros 1y ago
I've been using a CGM on and off for the last year, and it has given me a whole new perspective about food and nutrition. I discovered that a bunch of things I thought were reasonably healthy actually caused huge glycemic spikes -- e.g., white bread in the morning, croissants, dried mangos, excessive amount of fruits, etc. I also discovered the importance of what you eat for your first meal in the day (either breakfast or lunch), or how to better order what you eat (fibers, fat and protein first, carbs last), light movement after eating reduces 20+ mg/dl, and more. At this point I don't even need to wear a CGM every day; I can tell my glucose level just by thinking of what I ate earlier. I still wear one when I'm traveling for work, as I know I'll have less control over food and calorie intake (airplane meals, restaurants, team lunches, etc). ps: if you're interested in learning more even without using a CGM, strongly recommend "Glucose Revolution" [1]. [1] Glucose Revolution: The Life-Changing Power of Balancing Your Blood Sugar - https://www.amazon.com/Glucose-Revolution-Life-Changing-Power-Balancing/dp/1982179414 https://www.amazon.com/Glucose-Revolution-Life-Changing-Powe...
- alexey-salmin 1y ago
  > I discovered that a bunch of things I thought were reasonably healthy actually caused huge glycemic spikes -- e.g., white bread in the morning, croissants, dried mangos, excessive amount of fruits, etc. I wonder if this amounts to optimization of an easy-to-measure and reasonably-looking but incorrect metric, much like the previous "common sense" wave of "fat makes you fat" that led several generations into a dead end. You assume above that glycemic spikes are unhealthy which I think was never proven for the general population. Eating too much sugar or eating too much in general is bad, but I'm not aware of evidence that croissants kill you if you eat reasonably. Another thing to note: one of the potential suspects in the obesity epidemic is HFCS, and fructose doesn't actually cause glycemic spikes. If this turns out to be true, then parallels with the "fat makes you fat" theory become uncannily strong. I tend to think this could be the case because it matches my personal observations. I moved to France a few years ago and the amount of croissants I and people around me consume is at the stereotypes level. My weight is stable but each time I go to US for a couple of weeks I bring back 3-5 extra kilos. Something is seriously different between the food here and there, and I don't think it's glycemic spikes per se.
utopcell 1y ago
I share the author's enthusiasm about GCM devices. I am also finding that I need to change the over-patch long before the 15-day window because it gets messed up. I've found these [1] quite useful. [1] https://www.amazon.com/dp/B0C4PKMJTN https://www.amazon.com/dp/B0C4PKMJTN
tinyoli 1y ago
A bit an older post with more data on the topic: https://medium.com/better-humans/measuring-blood-sugar-as-a-non-diabetic-a34533cf571d https://medium.com/better-humans/measuring-blood-sugar-as-a-... TL;DR: As a healthy, non-diabetic adult I wore a Continuous Glucose Monitor (CGM) to measure my blood sugar for two weeks The sensor was convenient to use and painless to apply, and was barely noticeable during the two weeks it was on my arm. In analyzing my blood sugar levels, I learned a lot about my body’s response to different foods and exercise; I could identify some foods that spike my glucose. Two weeks is too short to make detailed improvements to my nutrition in order to stabilise glucose levels — further monitor and experimentation will be needed.
WatchDog 1y ago
I've been using "freestyle libre" devices on my diabetic cat, but they are quite expensive(~$110 AUD), and typically don't last the whole 14 day period before failing. Although I imagine they are much more reliable on a human. I've stopped using them because it's just a bit too expensive, and my cat's diabetes is more stable now. I opened up a freestyle libre 2, it has a EM9304 bluetooth SOC, and a TI RF430 NFC microcontroller, chatgpt deepresearch estimated the bill of materials to be about $5 USD[0]. Some companies[1] are developing reusable CGMs, the electronics are reusable, but the glucose oxidase probe, and applicator needle are still consumable. I'm not sure if that will bring the costs down much, it doesn't seem like the BOM is the main factor in the price of existing CGMs anyway. [0]: https://chatgpt.com/share/686225c7-11ac-8005-aa4a-f420415e2171 https://chatgpt.com/share/686225c7-11ac-8005-aa4a-f420415e21... [1]: https://www.rightest.com/global/rightestifree2cgm/ https://www.rightest.com/global/rightestifree2cgm/
- vineyardmike 1y ago
  > it doesn't seem like the BOM is the main factor in the price of existing CGMs anyway No. A huge reason for the cost is (1) costs in R&D but also (2) the customer service/replacement requirements/etc required for medical devices. If you were diabetic, and had a prescription for these devices, you'd be able to call Abott/Dexcom and get a replacement to a failed device shipped to you overnight. If the device didn't last the fully spec'd lifespan, you'd be eligible for replacements... etc
  - mlsu 1y ago
    And on R&D; the QC bar for software and manufacturing is much higher. Every process has validation testing. So it is expensive both in R&D and manufacturing. Another thing is that these off the shelf CGMs don't really differ in quality to their prescription only counterparts, which have a pretty extreme risk profile (patient death or hospitalization if it spits out the wrong number). They use the same parts so those costs are inherited.
- hammyhavoc 1y ago
  How does the adhesive of the CGM and fur work?
tptacek 1y ago
In a couple of cases, meals that I thought would be fairly healthy (or at least not terrible) were pretty terrible. There'll be some things that I'll avoid eating more than I had before. Someone chime in with what they think these might be! Should I be eating less broccoli?
- yegle 1y ago
  King's Hawaiian Roll. It doesn't taste like it contains a lot of sugars, at least not as sweet as other desserts like a cake. But two rolls (weight wise, very small amount) would send my glucose to sky high.
hyperbolablabla 1y ago
> "i would be amiss" Huh, never seen that typo before. Should be "remiss"
- properclass 1y ago
  https://en.m.wiktionary.org/wiki/amiss https://en.m.wiktionary.org/wiki/amiss I think it is fine. It would be remiss of me to say otherwise.
ars 1y ago
I wore one, but had some trouble with the glue, by day 8 or so it seemed like it was on the verge of falling off, so I added some medical tape which annoyed my skin. I suspect these devices will never go beyond 14 days at a time simply because of the glue issue. My skin was also pretty irritated once I removed the device, with some blood where the device sat. If you chose to wear one, especially in the summer, work very hard at removing all oils from your skin before you apply it. Soap and water (preferably real soap, not SLS), and then alcohol to get everything. I discovered that my wake/sleep cycle affected my blood sugar as much as, or even more than, what I ate.
- duskwuff 1y ago
  > I suspect these devices will never go beyond 14 days at a time simply because of the glue issue. The sensor chemically wears out over time too - the time limit is based on how long the manufacturer can guarantee good readings for.
- stkhlm 1y ago
  Some people do have a lot of issues with the adhesive and skin reactions. I am lucky and don't have that. I use an Anubis, a modified Dexcom G6, (https://www.loopandlearn.org/anubis/ https://www.loopandlearn.org/anubis/), which allows up to 60 days of wear. Although realistically I've never gone over 25 days. This is with adding over patches as the adhesive starts to fail though. The one I'm wearing right now is on day 18 and still doing great. After day 10-12 I also start to do daily checks with a blood glucose meter to verify that the readings from the CGM are still correct.
- thoughtpalette 1y ago
  I had the same issue with the Stelo tape. There's plenty of aftermarket tapes on amazon that fit the device profiles perfectly.
yegle 1y ago
If you use Android, you absolutely should try Juggluco (https://www.juggluco.nl/Juggluco/index.html https://www.juggluco.nl/Juggluco/index.html) It's open source and supports all CGM sensors that I know of. It has the ability to "broadcast" your data to various destinations and has a built-in https server to export a quick summary view to share with your doctor. It also supports exporting to Abbot LibreView so your significant others can use the LibreView app to view your data. Don't be intimidated by the UI: it's weird and seemingly outdated, but EVERY part of the UI has a dedicated "help" button that you can click and read for details. Couldn't be happier since I ditched the Freestyle Libre app (it failed to open after an Android update).
- sdpy 1y ago
  There is also an open-source project Nightscout (CGM in the Cloud) which supports Android and iOS: https://github.com/nightscout https://github.com/nightscout
- geor9e 1y ago
  That's interesting, it's almost identical to the xDrip+ android app that has been doing all those things for ~10 years. I wonder why they started from scratch instead of just forking the more popular open source app. Maybe it is a fork, it's not totally clear from that page.
ViscountPenguin 1y ago
Is there any actual data on the long term use of these devices in non-diabetics? This feels like geek bait, imo. A nice simple metric to obsess over, and to optimise. With a super simple (therefore presumably wrong) biological model to back up it's worth. It seems to be, that nothing particularly good has come of prior trends in quantified self-health (for regular consumers, pun intended, at least); and this seems to come packaged with a very real risk of orthorexia.
- randomcarbloke 1y ago
  I think it's definitely geek-bait, I wore one for a few months and would say that unless you have diabetes/pre-diabetes it's a waste of time.
- lame-robot-hoax 1y ago
  It is geek bait — most people read too far into these “spikes” and cut out healthy foods in doing so. It’s taking literally one metric as gospel which is moronic to be frank.
  - const_cast 1y ago
    Yes, and elephant in the room - we already have very good measurements for diabetes risk that doctor's look at, A1C. It doesn't matter much how your glucose happens to be at a point in time because diabetes is a chronic condition that takes a very long time to develop, which is why doctor's aren't going to be looking at your glucose anyway. You can obsess over your glucose all you want, but if you aren't lowering your A1C then you aren't lowering your risk.
imjonse 1y ago
The author does not seem to go into details, so I am curious what actually surprising conclusions can be drawn from wearing one of these devices? Croissants and muffins being unhealthy should be no surprise. I am more interested in findings like food that gets a bad rap being not that unhealthy and supposedly healthy food being bad.
- Llamamoe 1y ago
  Pizza is much more nutritionally complete than you'd think, especially if it has meat(or beans, for some reason), the only real problem is people eat SO MUCH at a time. People also refuse to understand that juice is basically sugar water with some extra flavor, vitamins, and antioxidants that don't change how unhealthy it is for you. White rice is basically pure carbs with barely any nutrients. Fastfood is heavily processed but often contains enough vegetables, meat, etc to not be that bad all things told.
  - petesergeant 1y ago
    > White rice is basically pure carbs with barely any nutrients. I am reasonably sure carbohydrates are nutrients.
  - hombre_fatal 1y ago
    > White rice is basically pure carbs with barely any nutrients. You should fact check your intuitions about nutrition on cronometer.com. 2 cups of cooked white rice have 17% of the days nutrients for 20% (400) of the calories (2000cal/day). 47% of the day's iron, 33% of the day's folate. 20-30% of almost every B-vitamin. 25% copper, 65% manganese, 43% selenium, 14% of the day's zinc. Also look at 500g of boiled potato. Someone in this thread called it pure carbs. Ok, pure carbs that give you 27% of the day's nutrients for just 18% of the day's calories? That's a great deal.
    - Llamamoe 1y ago
      Other than folate and B12, the B vitamins are the most common nutrients, they're not really a point in rice's favor. And other than manganese, the other figures you quote are MUCH higher than the sources I'm looking at. Are you sure you're not looking at enriched rice, or an unusually nutrient-rich strain? Because rice absolutely is the least nutritive staple crop of the ones commonly consumed in the first world.
thor-rodrigues 1y ago
What I find absolutely infuriating is that Abott (Freestyle Libre 1-3 devices) region locks their monitoring app depending on your region. My father is T1 is uses the Libre CGM system for a couple years now. Libre users in the US and Europe can enjoy direct integration with their iOS devices, including constant updates and most importantly, notification alerts for dangerously high or low glucose levels, and it is even possible to share live updates of this with close family members or caretakers. But none of this is available for my dad, as he lives in Brazil. Even though the product is same, he cannot download the iOS apps over the AppStore, as they are region locked.
- qsi 1y ago
  Is that because Brazilian regulations prohibit it? Or lawyers being too cautious?
martind81 1y ago
What CGM device would you recommend for a first try?
- stkhlm 1y ago
  Which ever you can get from Dexcom or Abbott. They're pretty good all of them. Dexcom Stelo is probably the easiest to get a hold of, and the one talked about in the article too.
yegle 1y ago
For me the best insight learned from wearing a GCM is that a cardio exercise with 150bpm heart rate for 40min+ is probably not healthy. I would easily see my glucose level drop to below 80 mg/dL (5 mmol/L) 30min into the exercise. I always thought the exhaustion towards the end of my exercise was due to normal fatigue, and never thought it was caused by hypoglycemia. Now I would exercise and closely monitor my glucose level, then adjust my intensity when it dip lower than 100 mg/dL (5.5 mmol/L). It made the cardio exercise much more bearable, and easier to stick to it as a daily routine.
- Youden 1y ago
  Rather than show that such exercise is unhealthy, I think it simply shows you need to consume some glucose during. There's a reason aside from taste that sports drinks all contain a helping of glucose. I can't recall if I saw them in the US but in Europe many supermarkets offer products like "Dextro Energy", which is essentially just a sugar tablet advertised to people who need glucose during sports.
- defyonce 1y ago
  this, 100% i've been running 35km while fasted for 36 hours, and it is way more difficult than when you allow yourself to eat a snickers on the way. now i am running my weekly half-marathons with something sweet, and it has been awesome. Like really no big deal.
- aw1621107 1y ago
  As sibling comments stated, that's why you see recommendations to eat during longer exercise sessions. A common recommendation I've seen is that for an hour or less of activity your internal stores should suffice, but for more than an hour 30-90 grams of (probably easy-to-digest) carbs per hour of exercise is recommended.
- vlod 1y ago
  Stupid question (layman). If it drops below 80 mg/fl, are there not mechanisms in the body to increase it? i.e. shouldn't the liver dump glucose into the blood stream to compensate? Failing that, shouldn't hormones be activated to cause fat be broken down into energy?
mondocat 1y ago
I wore a monitor for two weeks. As someone who basically does not eat processed food, including sugar, and has 4-5 meals a day always including vegetables/fiber it was not obvious that what I ate had any reliable impact on the count. It would go up and down seemingly at random throughout the day and night. The highest and most reliable spikes came when I was lifting weights. Likewise cardio, especially high intensity cardio made it drop to its lowest levels. The most interesting outcome was that the late afternoon hanger I often felt was not associated with a dip (or change at all) in blood glucose as I expected it would be, so that remains a mystery.
- randomcarbloke 1y ago
  as someone who eats relatively healthily but has no problem consuming processed foods (but tends to avoid excessive sugar), when I wore a cgm out of curiosity it was very clear that such a device offered me nothing, as a non-diabetic, non-pre-diabetic person the data showed that the body responds in line with input never exceeding tolerances. It was impressive just how uninsightful it was, I love quantifying my workouts, my nutrient intake, etc, but the cgm added absolutely nothing.
mulle_nat 1y ago
People should get on the bike and start cycling for real (like burn 200W an hour). Their perception of glucose will flip 100%. Suddenly glucose is like the fuel to your body, that you can't cram enough into. Which means white bread in the morning, croissants (and coca cola with sugar) will be your friends. Quite frankly a much better lifestyle.
- painted 1y ago
  until you realize the sugar is also bad for your teeth, for example
cigs645 1y ago
CGMs are a great but if you wish to lose weight you have to create a calorie deficit as opposed to a surplus harder to do in our carbs heavy, sugar loaded, ultra processed foods dominated diets which are extremely unhealthy for us. I know I went from a 7.1 A1C(type 2 diabetes) to a 5.3 A1C(no diabetes) in a little over a month by going on a Keto diet while laying off the carbs and exercising regularly. If you don't CGM or not you'll end up like the almost 1/3 of the US population or 98 million Americans who are currently pre diabetic looking to join the 38.4 million who are already full blown diabetics a condition often called the silent killer for good reason (heart disease, stroke, chronic inflammation, kidney disease, nerve damage, and vision loss). Chronic inflammation also thought to have a direct link with cancer
- hammyhavoc 1y ago
  A1C measured by blood draw or guesstimated by CGM data algorithmically?
cynicalsecurity 1y ago
If you don't have diabetes type 1 or type 2, or temporary diabetes related to pregnancy, then you don't really need a CGM. CGM is a life-saving tool for people with diabetes type 1 mostly. I was hugely ignorant of diabetes type 1 before my child suddenly was diagnosed with it. It's an absolute nightmare, a horrifying disease no one is taking about while there are millions of children affected by it worldwide - and the disease is spreading, getting worse every year. It's astonishing how many unknowns there are in this disease.
dbbljack 1y ago
if you don't need alerts for extreme high/low, i don't see the value of cgm monitoring... starch/grain/sugar spikes insulin, protein gives gentle raise within 3-5 hours, fat does next to nothing and does in around 7-9 hours. mixing a bunch of fibre/fat/protein into your starch and sugar makes the insulin spike less intense... what are you guys learning about your super special non diabetic bodies that you can't learn with a $5 book of glycemic indices or a casual afternoon reading basic diabetes dieting advice?
AbstractH24 1y ago
I’m still waiting for a device that reliably measures ketones and glucose continuously Anyone know what ever happened to those?
geor9e 1y ago
Here's a teardown of the Stelo CGM https://news.ycombinator.com/item?id=43145527 https://news.ycombinator.com/item?id=43145527

116 points by zdw 1y ago

The author's mention of the Hawthorn Effect fascinated me; I hadn't considered that with devices your care team can monitor. It will change a lot of lives when some device that doesn't draw blood can continuously monitor glucose, like a smartwatch.

privatelypublic 1y ago
Pretty sure optical glucose is already a thing- it's just not very accurate yet.
- nmehner 1y ago
  https://www.fda.gov/medical-devices/safety-communications/do-not-use-smartwatches-or-smart-rings-measure-blood-glucose-levels-fda-safety-communication https://www.fda.gov/medical-devices/safety-communications/do... Existing smart watches that claim to do this are basically garbage. Just use a random number generator instead. Apple and Samsung are supposedly working on it: https://www.forbes.com/sites/davidphelan/2025/01/26/samsung-reveals-game-changer-blood-glucose-monitoring-to-outdo-apple-watch/ https://www.forbes.com/sites/davidphelan/2025/01/26/samsung-... But it seems to be hard and from what I have seen the new Galaxy Watch 8 won't have this feature.
  - leakycap 1y ago
    Great resources. It seems we'll see BP monitoring integrated in a mainstream base smartwatch before we'll get optical glucose monitoring.
  - privatelypublic 1y ago
    Smartphones are notorious for not delivering- heck, my fitbit won't even give me an actual wrist temp value. Theres optical ones that can be built in a lab and require profiling to an individual. The most accurate ones are still invasive- just not consumable fungus extract based. Maybe some biomedical company makes a reference design.
- leakycap 1y ago
  I have used my phone camera to determine blood pressure, but I have yet to see a common consumer device with optical glucose monitoring. I'm suggesting that it will change the world when it is an integrated part of something many/most of us buy and would eventually upgrade to.
  - ASalazarMX 1y ago
    > I have used my phone camera to determine blood pressure You mean heart rate? they cleverly work by flooding your skin with the flash LED, and looking for small differences indicative of a heartbeat. Blood pressure is not something you can image with a consumer camera.
    - privatelypublic 1y ago
      Camera? Yes. Normal illumination? No.
shreezus 1y ago
I believe we will see integrated optical glucose sensors in a popular consumer wearable fairly soon. I don't think they'll be as accurate as blood sensors, however they will be a game-changer for many people (pre-diabetics, or gestational diabetes etc).
sdpy 1y ago
That would be a game-changer for so many people. We're already getting close, though. Those CGMs like Dexcom don't actually test blood; they check interstitial fluid. There's a 5-15 minute delay, but still way better than finger pricks all day. Non-invasive monitoring is still tricky. There’ve been some interesting attempts—like GlucoWatch back in the early 2000s, which used mild electrical currents, but caused skin irritation and never really caught on. Others have tried optical monitoring, radio waves, ultrasound, and even heat-based sensors. Feels like we’re getting closer, just not quite there yet.
hammyhavoc 1y ago
GlucoWear is awaiting CE mark currently.

bix6 1y ago

I believe these cheaper devices are not very accurate ie accuracy range of 20% which is a fairly wide window. I’ve also heard there are many things that can impact your glucose even with the same meal like time of day, exercise, stress, sleep, etc. So if you actually want to find the patterns you’d need the expensive CGM over many months.

loremm 1y ago
Is that true? I have no perspective but it's relied on by diabetics and if since they can't regulate it themselves, if the readings are off and they gave themselves insulin, they would know it is wrong. Maybe the OTC ones is different than the diabetic one but I didn't think so
- privatelypublic 1y ago
  They're not any different. CGM's have issues- sometimes need to be calibrated against a finger stick (officially, they always need to be) In the end though- it's still a bit of fungal extract painted onto an electrode, and an ADC that reads the value every so often. Like any other glucose monitor.
  - deleted 1y ago
    [deleted]
- djur 1y ago
  Stelo is basically just a consumer packaged version of the Dexcom G6, and in both cases they warn you to use a finger stick to verify unexpected readings. But finger sticks can be really inaccurate, too. For many diabetics it's not a life-or-death matter (only 1 in 4 type 2 patients end up using insulin), and the important thing is the trend over time. I've personally found my CGM to be really useful in understanding the effect of diet, sleep, stress, etc. on my blood glucose, like the OP says, but you definitely get some weird readings sometimes. Yesterday a new unit told me that my blood glucose dropped below 70 for 2 hours. It definitely didn't! After a while it got itself straightened out in time to scold me for eating some corn chips.

guiambros 1y ago

I've been using a CGM on and off for the last year, and it has given me a whole new perspective about food and nutrition. I discovered that a bunch of things I thought were reasonably healthy actually caused huge glycemic spikes -- e.g., white bread in the morning, croissants, dried mangos, excessive amount of fruits, etc. I also discovered the importance of what you eat for your first meal in the day (either breakfast or lunch), or how to better order what you eat (fibers, fat and protein first, carbs last), light movement after eating reduces 20+ mg/dl, and more. At this point I don't even need to wear a CGM every day; I can tell my glucose level just by thinking of what I ate earlier. I still wear one when I'm traveling for work, as I know I'll have less control over food and calorie intake (airplane meals, restaurants, team lunches, etc). ps: if you're interested in learning more even without using a CGM, strongly recommend "Glucose Revolution" [1]. [1] Glucose Revolution: The Life-Changing Power of Balancing Your Blood Sugar - https://www.amazon.com/Glucose-Revolution-Life-Changing-Power-Balancing/dp/1982179414 https://www.amazon.com/Glucose-Revolution-Life-Changing-Powe...

alexey-salmin 1y ago
> I discovered that a bunch of things I thought were reasonably healthy actually caused huge glycemic spikes -- e.g., white bread in the morning, croissants, dried mangos, excessive amount of fruits, etc. I wonder if this amounts to optimization of an easy-to-measure and reasonably-looking but incorrect metric, much like the previous "common sense" wave of "fat makes you fat" that led several generations into a dead end. You assume above that glycemic spikes are unhealthy which I think was never proven for the general population. Eating too much sugar or eating too much in general is bad, but I'm not aware of evidence that croissants kill you if you eat reasonably. Another thing to note: one of the potential suspects in the obesity epidemic is HFCS, and fructose doesn't actually cause glycemic spikes. If this turns out to be true, then parallels with the "fat makes you fat" theory become uncannily strong. I tend to think this could be the case because it matches my personal observations. I moved to France a few years ago and the amount of croissants I and people around me consume is at the stereotypes level. My weight is stable but each time I go to US for a couple of weeks I bring back 3-5 extra kilos. Something is seriously different between the food here and there, and I don't think it's glycemic spikes per se.

utopcell 1y ago

I share the author's enthusiasm about GCM devices. I am also finding that I need to change the over-patch long before the 15-day window because it gets messed up. I've found these [1] quite useful. [1] https://www.amazon.com/dp/B0C4PKMJTN https://www.amazon.com/dp/B0C4PKMJTN

tinyoli 1y ago

A bit an older post with more data on the topic: https://medium.com/better-humans/measuring-blood-sugar-as-a-non-diabetic-a34533cf571d https://medium.com/better-humans/measuring-blood-sugar-as-a-... TL;DR: As a healthy, non-diabetic adult I wore a Continuous Glucose Monitor (CGM) to measure my blood sugar for two weeks The sensor was convenient to use and painless to apply, and was barely noticeable during the two weeks it was on my arm. In analyzing my blood sugar levels, I learned a lot about my body’s response to different foods and exercise; I could identify some foods that spike my glucose. Two weeks is too short to make detailed improvements to my nutrition in order to stabilise glucose levels — further monitor and experimentation will be needed.

WatchDog 1y ago

I've been using "freestyle libre" devices on my diabetic cat, but they are quite expensive(~$110 AUD), and typically don't last the whole 14 day period before failing. Although I imagine they are much more reliable on a human. I've stopped using them because it's just a bit too expensive, and my cat's diabetes is more stable now. I opened up a freestyle libre 2, it has a EM9304 bluetooth SOC, and a TI RF430 NFC microcontroller, chatgpt deepresearch estimated the bill of materials to be about $5 USD[0]. Some companies[1] are developing reusable CGMs, the electronics are reusable, but the glucose oxidase probe, and applicator needle are still consumable. I'm not sure if that will bring the costs down much, it doesn't seem like the BOM is the main factor in the price of existing CGMs anyway. [0]: https://chatgpt.com/share/686225c7-11ac-8005-aa4a-f420415e2171 https://chatgpt.com/share/686225c7-11ac-8005-aa4a-f420415e21... [1]: https://www.rightest.com/global/rightestifree2cgm/ https://www.rightest.com/global/rightestifree2cgm/

vineyardmike 1y ago
> it doesn't seem like the BOM is the main factor in the price of existing CGMs anyway No. A huge reason for the cost is (1) costs in R&D but also (2) the customer service/replacement requirements/etc required for medical devices. If you were diabetic, and had a prescription for these devices, you'd be able to call Abott/Dexcom and get a replacement to a failed device shipped to you overnight. If the device didn't last the fully spec'd lifespan, you'd be eligible for replacements... etc
- mlsu 1y ago
  And on R&D; the QC bar for software and manufacturing is much higher. Every process has validation testing. So it is expensive both in R&D and manufacturing. Another thing is that these off the shelf CGMs don't really differ in quality to their prescription only counterparts, which have a pretty extreme risk profile (patient death or hospitalization if it spits out the wrong number). They use the same parts so those costs are inherited.
hammyhavoc 1y ago
How does the adhesive of the CGM and fur work?

tptacek 1y ago

In a couple of cases, meals that I thought would be fairly healthy (or at least not terrible) were pretty terrible. There'll be some things that I'll avoid eating more than I had before. Someone chime in with what they think these might be! Should I be eating less broccoli?

yegle 1y ago
King's Hawaiian Roll. It doesn't taste like it contains a lot of sugars, at least not as sweet as other desserts like a cake. But two rolls (weight wise, very small amount) would send my glucose to sky high.

hyperbolablabla 1y ago

> "i would be amiss" Huh, never seen that typo before. Should be "remiss"

properclass 1y ago
https://en.m.wiktionary.org/wiki/amiss https://en.m.wiktionary.org/wiki/amiss I think it is fine. It would be remiss of me to say otherwise.

ars 1y ago

I wore one, but had some trouble with the glue, by day 8 or so it seemed like it was on the verge of falling off, so I added some medical tape which annoyed my skin. I suspect these devices will never go beyond 14 days at a time simply because of the glue issue. My skin was also pretty irritated once I removed the device, with some blood where the device sat. If you chose to wear one, especially in the summer, work very hard at removing all oils from your skin before you apply it. Soap and water (preferably real soap, not SLS), and then alcohol to get everything. I discovered that my wake/sleep cycle affected my blood sugar as much as, or even more than, what I ate.

duskwuff 1y ago
> I suspect these devices will never go beyond 14 days at a time simply because of the glue issue. The sensor chemically wears out over time too - the time limit is based on how long the manufacturer can guarantee good readings for.
stkhlm 1y ago
Some people do have a lot of issues with the adhesive and skin reactions. I am lucky and don't have that. I use an Anubis, a modified Dexcom G6, (https://www.loopandlearn.org/anubis/ https://www.loopandlearn.org/anubis/), which allows up to 60 days of wear. Although realistically I've never gone over 25 days. This is with adding over patches as the adhesive starts to fail though. The one I'm wearing right now is on day 18 and still doing great. After day 10-12 I also start to do daily checks with a blood glucose meter to verify that the readings from the CGM are still correct.
thoughtpalette 1y ago
I had the same issue with the Stelo tape. There's plenty of aftermarket tapes on amazon that fit the device profiles perfectly.

yegle 1y ago

If you use Android, you absolutely should try Juggluco (https://www.juggluco.nl/Juggluco/index.html https://www.juggluco.nl/Juggluco/index.html) It's open source and supports all CGM sensors that I know of. It has the ability to "broadcast" your data to various destinations and has a built-in https server to export a quick summary view to share with your doctor. It also supports exporting to Abbot LibreView so your significant others can use the LibreView app to view your data. Don't be intimidated by the UI: it's weird and seemingly outdated, but EVERY part of the UI has a dedicated "help" button that you can click and read for details. Couldn't be happier since I ditched the Freestyle Libre app (it failed to open after an Android update).

sdpy 1y ago
There is also an open-source project Nightscout (CGM in the Cloud) which supports Android and iOS: https://github.com/nightscout https://github.com/nightscout
geor9e 1y ago
That's interesting, it's almost identical to the xDrip+ android app that has been doing all those things for ~10 years. I wonder why they started from scratch instead of just forking the more popular open source app. Maybe it is a fork, it's not totally clear from that page.

ViscountPenguin 1y ago

Is there any actual data on the long term use of these devices in non-diabetics? This feels like geek bait, imo. A nice simple metric to obsess over, and to optimise. With a super simple (therefore presumably wrong) biological model to back up it's worth. It seems to be, that nothing particularly good has come of prior trends in quantified self-health (for regular consumers, pun intended, at least); and this seems to come packaged with a very real risk of orthorexia.

randomcarbloke 1y ago
I think it's definitely geek-bait, I wore one for a few months and would say that unless you have diabetes/pre-diabetes it's a waste of time.
lame-robot-hoax 1y ago
It is geek bait — most people read too far into these “spikes” and cut out healthy foods in doing so. It’s taking literally one metric as gospel which is moronic to be frank.
- const_cast 1y ago
  Yes, and elephant in the room - we already have very good measurements for diabetes risk that doctor's look at, A1C. It doesn't matter much how your glucose happens to be at a point in time because diabetes is a chronic condition that takes a very long time to develop, which is why doctor's aren't going to be looking at your glucose anyway. You can obsess over your glucose all you want, but if you aren't lowering your A1C then you aren't lowering your risk.

imjonse 1y ago

The author does not seem to go into details, so I am curious what actually surprising conclusions can be drawn from wearing one of these devices? Croissants and muffins being unhealthy should be no surprise. I am more interested in findings like food that gets a bad rap being not that unhealthy and supposedly healthy food being bad.

Llamamoe 1y ago
Pizza is much more nutritionally complete than you'd think, especially if it has meat(or beans, for some reason), the only real problem is people eat SO MUCH at a time. People also refuse to understand that juice is basically sugar water with some extra flavor, vitamins, and antioxidants that don't change how unhealthy it is for you. White rice is basically pure carbs with barely any nutrients. Fastfood is heavily processed but often contains enough vegetables, meat, etc to not be that bad all things told.
- petesergeant 1y ago
  > White rice is basically pure carbs with barely any nutrients. I am reasonably sure carbohydrates are nutrients.
- hombre_fatal 1y ago
  > White rice is basically pure carbs with barely any nutrients. You should fact check your intuitions about nutrition on cronometer.com. 2 cups of cooked white rice have 17% of the days nutrients for 20% (400) of the calories (2000cal/day). 47% of the day's iron, 33% of the day's folate. 20-30% of almost every B-vitamin. 25% copper, 65% manganese, 43% selenium, 14% of the day's zinc. Also look at 500g of boiled potato. Someone in this thread called it pure carbs. Ok, pure carbs that give you 27% of the day's nutrients for just 18% of the day's calories? That's a great deal.
  - Llamamoe 1y ago
    Other than folate and B12, the B vitamins are the most common nutrients, they're not really a point in rice's favor. And other than manganese, the other figures you quote are MUCH higher than the sources I'm looking at. Are you sure you're not looking at enriched rice, or an unusually nutrient-rich strain? Because rice absolutely is the least nutritive staple crop of the ones commonly consumed in the first world.

thor-rodrigues 1y ago

What I find absolutely infuriating is that Abott (Freestyle Libre 1-3 devices) region locks their monitoring app depending on your region. My father is T1 is uses the Libre CGM system for a couple years now. Libre users in the US and Europe can enjoy direct integration with their iOS devices, including constant updates and most importantly, notification alerts for dangerously high or low glucose levels, and it is even possible to share live updates of this with close family members or caretakers. But none of this is available for my dad, as he lives in Brazil. Even though the product is same, he cannot download the iOS apps over the AppStore, as they are region locked.

qsi 1y ago
Is that because Brazilian regulations prohibit it? Or lawyers being too cautious?

martind81 1y ago

What CGM device would you recommend for a first try?

stkhlm 1y ago
Which ever you can get from Dexcom or Abbott. They're pretty good all of them. Dexcom Stelo is probably the easiest to get a hold of, and the one talked about in the article too.

yegle 1y ago

For me the best insight learned from wearing a GCM is that a cardio exercise with 150bpm heart rate for 40min+ is probably not healthy. I would easily see my glucose level drop to below 80 mg/dL (5 mmol/L) 30min into the exercise. I always thought the exhaustion towards the end of my exercise was due to normal fatigue, and never thought it was caused by hypoglycemia. Now I would exercise and closely monitor my glucose level, then adjust my intensity when it dip lower than 100 mg/dL (5.5 mmol/L). It made the cardio exercise much more bearable, and easier to stick to it as a daily routine.

Youden 1y ago
Rather than show that such exercise is unhealthy, I think it simply shows you need to consume some glucose during. There's a reason aside from taste that sports drinks all contain a helping of glucose. I can't recall if I saw them in the US but in Europe many supermarkets offer products like "Dextro Energy", which is essentially just a sugar tablet advertised to people who need glucose during sports.
defyonce 1y ago
this, 100% i've been running 35km while fasted for 36 hours, and it is way more difficult than when you allow yourself to eat a snickers on the way. now i am running my weekly half-marathons with something sweet, and it has been awesome. Like really no big deal.
aw1621107 1y ago
As sibling comments stated, that's why you see recommendations to eat during longer exercise sessions. A common recommendation I've seen is that for an hour or less of activity your internal stores should suffice, but for more than an hour 30-90 grams of (probably easy-to-digest) carbs per hour of exercise is recommended.
vlod 1y ago
Stupid question (layman). If it drops below 80 mg/fl, are there not mechanisms in the body to increase it? i.e. shouldn't the liver dump glucose into the blood stream to compensate? Failing that, shouldn't hormones be activated to cause fat be broken down into energy?

mondocat 1y ago

I wore a monitor for two weeks. As someone who basically does not eat processed food, including sugar, and has 4-5 meals a day always including vegetables/fiber it was not obvious that what I ate had any reliable impact on the count. It would go up and down seemingly at random throughout the day and night. The highest and most reliable spikes came when I was lifting weights. Likewise cardio, especially high intensity cardio made it drop to its lowest levels. The most interesting outcome was that the late afternoon hanger I often felt was not associated with a dip (or change at all) in blood glucose as I expected it would be, so that remains a mystery.

randomcarbloke 1y ago
as someone who eats relatively healthily but has no problem consuming processed foods (but tends to avoid excessive sugar), when I wore a cgm out of curiosity it was very clear that such a device offered me nothing, as a non-diabetic, non-pre-diabetic person the data showed that the body responds in line with input never exceeding tolerances. It was impressive just how uninsightful it was, I love quantifying my workouts, my nutrient intake, etc, but the cgm added absolutely nothing.

mulle_nat 1y ago

People should get on the bike and start cycling for real (like burn 200W an hour). Their perception of glucose will flip 100%. Suddenly glucose is like the fuel to your body, that you can't cram enough into. Which means white bread in the morning, croissants (and coca cola with sugar) will be your friends. Quite frankly a much better lifestyle.

painted 1y ago
until you realize the sugar is also bad for your teeth, for example

cigs645 1y ago

CGMs are a great but if you wish to lose weight you have to create a calorie deficit as opposed to a surplus harder to do in our carbs heavy, sugar loaded, ultra processed foods dominated diets which are extremely unhealthy for us. I know I went from a 7.1 A1C(type 2 diabetes) to a 5.3 A1C(no diabetes) in a little over a month by going on a Keto diet while laying off the carbs and exercising regularly. If you don't CGM or not you'll end up like the almost 1/3 of the US population or 98 million Americans who are currently pre diabetic looking to join the 38.4 million who are already full blown diabetics a condition often called the silent killer for good reason (heart disease, stroke, chronic inflammation, kidney disease, nerve damage, and vision loss). Chronic inflammation also thought to have a direct link with cancer

hammyhavoc 1y ago
A1C measured by blood draw or guesstimated by CGM data algorithmically?

cynicalsecurity 1y ago

If you don't have diabetes type 1 or type 2, or temporary diabetes related to pregnancy, then you don't really need a CGM. CGM is a life-saving tool for people with diabetes type 1 mostly. I was hugely ignorant of diabetes type 1 before my child suddenly was diagnosed with it. It's an absolute nightmare, a horrifying disease no one is taking about while there are millions of children affected by it worldwide - and the disease is spreading, getting worse every year. It's astonishing how many unknowns there are in this disease.

dbbljack 1y ago

if you don't need alerts for extreme high/low, i don't see the value of cgm monitoring... starch/grain/sugar spikes insulin, protein gives gentle raise within 3-5 hours, fat does next to nothing and does in around 7-9 hours. mixing a bunch of fibre/fat/protein into your starch and sugar makes the insulin spike less intense... what are you guys learning about your super special non diabetic bodies that you can't learn with a $5 book of glycemic indices or a casual afternoon reading basic diabetes dieting advice?

AbstractH24 1y ago

I’m still waiting for a device that reliably measures ketones and glucose continuously Anyone know what ever happened to those?

geor9e 1y ago

Here's a teardown of the Stelo CGM https://news.ycombinator.com/item?id=43145527 https://news.ycombinator.com/item?id=43145527