Testosterone has been declining in the population for decades. The reference levels for "normal" 20 year old now include what were, 60 years ago, levels conside

Testosterone has been declining in the population for decades. The reference levels for "normal" 20 year old now include what were, 60 years ago, levels considered too low for a ~60 year old man. It's not an exaggeration to say that at least a third of men have never experienced a normal hormonal level of testosterone. Testosterone affects nearly everything about the male physical and mental state; not only the stereotypical aggression and lust, but also mental clarity, happiness, even health.