Removing testes in male mice extended median lifespan by up to 32.9%, most with late surgery
In an experiment at the University of Texas at San Antonio, male mice lived longer after testis removal, and the effect grew with the age at surgery. The work is a preprint.
Researchers at the University of Texas at San Antonio found that surgical removal of the testes extended the median lifespan of male laboratory mice by up to 32.9%, according to portal.abczdrowie.pl portal.abczdrowie.pl
portal.abczdrowie.plportal.abczdrowie.plOpen source ↗. The study was posted on 24 October 2026 on the bioRxiv.org platform as a preprint that has not yet undergone peer review. The longest-lived animals were those operated on at a mature age.
Experimental design
The question behind the work is why men live on average shorter than women. Researchers have long tried to establish how much of this difference is due to biological factors, including sex hormones. To test one part of it, the team used male laboratory mice divided into three groups.
All animals had their testes removed surgically, but at different stages of life. The first group was operated on at 20 days of age, before sexual maturity. The second group underwent surgery at 60 days, and the third at 240 days. The results were compared with control groups.
Results and limits
Median lifespan increased in all three groups relative to the pooled controls. The gain was 19.3% in the mice operated on earliest, 25.8% in the second group and 32.9% in the third portal.abczdrowie.pl
portal.abczdrowie.plportal.abczdrowie.plOpen source ↗. The animals that had their testes removed relatively late therefore lived longest.
The authors' results suggest that substances produced by the testes may play different roles depending on the age of the organism. Earlier in life their action may be beneficial, while later some of the related mechanisms may increase the risk of death. The finding may help in the search for mechanisms behind the difference in lifespan between women and men. Researchers are considering whether therapies could be developed in the future to limit the adverse effects of selected testis-related factors without removing the organs.
The experiment was carried out only on mice. It does not show that castration extends life in men, or that lowering testosterone is a safe route to longevity. The data come from a preprint and await peer review.
