Testosterone levels in men have declined by more than 50% over the past fifty years, at a rate of more than 1% per year.
This came in a statement by Professor Hagai Levine of the Hebrew University in Jerusalem.
Levin and his colleagues analyzed six major studies, which included data from nearly 120,000 men from Israel, the United States, Brazil, Finland and Denmark, during the period between 1972 and 2019.
Testosterone is known to affect libido, muscle mass, bone health, mood, and sperm production. Scientists attribute part of this decline to obesity, as excess fat leads to the conversion of testosterone into estrogen.
The relationship between testosterone levels in men and their health is a complex, two-way street. Testosterone regulates sperm production, influences libido, contributes to muscle growth and bone density maintenance, and is involved in mood regulation, energy balance, and metabolism. Factors such as obesity, in which excess fat accelerates the conversion of testosterone to estrogen, can lead to a decrease in testosterone levels.
But Levin's colleagues also do not rule out the influence of environmental factors, noting that researchers still need to determine the exact cause of this decline.
However, doctors warn against promoting testosterone supplements, as their use without a medical need can be risky. As andrologist Allan Pacey of the University of Manchester points out, taking this hormone can suppress a man's natural sperm production.
