Testosterone given from outside signals the brain to stop telling the testis to work, so sperm production and the testis's own hormone output shut down. This is why the World Health Organization studied it as a male contraceptive. The episode lays out the blood and other costs, and a fair reading of the Traverse cardiovascular trial: reassuring for the symptomatic men it enrolled, with no license for men with normal levels.
Who's who
- A. Michael Lincoff+1 more episodeLead author of the Traverse cardiovascular safety trial
- Gary WittertLead author of the T4DM diabetes trial
- Peter Snyder+1 more episodeReported the Testosterone Trials in 2016
Timeline
- 2006Pooled analysis shows sperm counts return in 67% of men by six months and 100% by twenty-four
- 2016Testosterone Trials report results for 788 men aged 65 and over
- 2021T4DM trial reports hematocrit above 0.54 in 22% of treated men versus 1% on placebo
- 2023Traverse reports no increase in major cardiac events in symptomatic hypogonadal men
- February 28, 2025FDA removes the cardiovascular boxed warning but adds a blood-pressure warning
Still debated
Traverse's reassurance applies to symptomatic, twice-confirmed hypogonadal men at high cardiac risk, and is being read to men it never enrolled. Secondary signals such as atrial fibrillation are hypothesis-generating, and reliable incidence figures for several side effects were not established.
