Men’s Testosterone Levels Have Fallen by 50% in the Last 50 Years

The Trend: Men may be experiencing a long-term decline in testosterone. According to data presented at the European Society of Human Reproduction and Embryology’s annual meeting, average testosterone levels fell by 54% between 1972 and 2019 after analyzing data from nearly 119,000 men across six long-term studies in five countries. 

What People Are Saying: Scientists agree the trend is concerning, but they’re still debating why it’s happening. Rising rates of obesity and diabetes are likely major contributors because both can suppress testosterone production. Researchers are also investigating whether endocrine-disrupting chemicals, air pollution, microplastics, and even climate-related stressors could play a role, though the evidence for these environmental factors is still emerging. They also caution that no single culprit has been identified. Regardless of the cause, we’re experiencing a “major crisis in male reproductive health,” one expert says.

What to Know: Testosterone is essential for sperm production, libido, muscle and bone health, mood, and energy. Lower levels may contribute to reduced fertility, though low testosterone doesn’t automatically equate to infertility. And doctors warn against frivolous hormone replacement therapy: it’s not an end-all, be-all cure for men’s health issues, and it is possible to overdo it.