If we had a drug that could restore sexual function in men, make them stronger, build their bones, reduce fat and get rid of the blues, you'd say, 'Oh my God, why doesn't everybody know about it?' There is a drug like that - but the public associates testosterone with cheating and illicit behavior and the fact that 40 years ago, it was thought to give people prostate cancer.
This one is written by a doctor:
A 20-year study of testosterone levels in men found that testosterone concentrations dropped about 1.2% per year, or about 17% overall, from 1987 to 2004. The downward trend was seen in both the population and in individuals over time.
Married men have lower testosterone levels than single guys.
It's estimated that two million to four million American men have a significant testosterone deficiency and that less than 5% of them are getting treatment.