Castration Extends Life — Scientists Confirmed This
An experiment on mice showed that removal of the testes can increase life expectancy by more than 30%. But researchers were surprised by the age at which the operation proved most effective.
Illustrative photo. Photo: FangXiaNuo / Getty Images
Women in most countries of the world live longer than men. For example, in Belarus, according to data from Belstat for 2024, the expected life expectancy for men was 69.3 years, and for women — 79.8 years. The difference is more than ten years.
This is partly explained by behavior and lifestyle, but the difference persists even when factors such as accidents, suicides, and homicides are taken into account. This indicates the existence of biological reasons as well.
One of these could be the influence of male gonads — the testes. As Science writes, scientists have long known that castration can increase the lifespan of males of various mammalian species. There are also historical studies on humans that indicate a similar effect.
Specifically, a 1969 study based on data from patients of a psychiatric institution who had been forcibly castrated in the past showed that they could live more than ten years longer than uncastrated men. And a 2025 analysis of data across 22 vertebrate species found a consistent increase in longevity after castration.
But for a long time, it remained unclear why this happens and whether it is necessary to remove the testes in youth to achieve such an effect.
Greatest Effect — in Adulthood
A team of researchers from the University of Texas Health Science Center at San Antonio decided to investigate how the age of castration affects life expectancy. For the experiment, they selected a line of laboratory mice in which females, similar to humans, consistently live longer than males.
Scientists divided the males into three groups. The first group was castrated before sexual maturity, the second — shortly after it, and the third — at the age of 240 days. For mice, this is already a respectable age, which researchers approximately compare to thirty human years.
The results were unexpected. In all three groups, castrated mice lived longer than those whose testes were not removed. But the greatest gain was observed in animals castrated in adulthood. Their median life expectancy increased by almost 33%. For comparison, castration before sexual maturity yielded an increase of about 19%, and immediately after it — about 26%.
Moreover, after the operation, none of the mice from the third group died for more than a year. This particularly impressed the researchers, as mortality among mice usually begins to increase at that age.
The results led to an unexpected hypothesis: in youth, the testes might even contribute to longevity, but with age, their influence becomes detrimental.
Why Does This Happen?
The testes produce more than 90% of testosterone in the male body. Therefore, one might assume that this hormone shortens life. However, scientists caution against hasty conclusions: castration causes numerous physiological changes, and it is not yet known which of them are responsible for the increase in life expectancy.
Interestingly, mice castrated in adulthood did not appear physically healthier than the others. With age, they similarly lost muscle strength and showed other signs of aging. This means that an increase in life expectancy does not necessarily coincide with a slowdown of all aging processes.
Researchers now want to find out what diseases the experimental animals died from, and identify the substances produced by the testes that may influence longevity.
In the future, this could help create drugs that mimic the positive effect of castration on life expectancy, but without the removal of the gonads and the associated consequences.