Castrating Older Mice Extends Their Lives by a Third, Upending Assumptions About Aging

The surprising part is that neutering males after puberty showed the larger increase:

> However, mice that were neutered as adults gained the most. The procedure stretched their lives by about 33%, compared with 19% and 26% increases, respectively, for the animals fixed before or after puberty.

That trend goes opposite of what would be expected from a simple area under the curve model where presence of the testes correlated with reduced lifespan.

The link between male hormones and aging has always been interesting but I think there’s going to be a renewed interest as TRT clinics have become common and even men who aren’t hypogonadal can now be prescribed TRT after a short consult with a doctor from their local clinic who never turns anyone down.

Among the people I know who were more cavalier with TRT and keeping their testosterone levels at the top of the normal range for years, all of them have started talking about how it feels they’ve aged. Anecdotally, they look older than their age to me, but I didn’t realize how much testosterone was associated with accelerated aging until I looked at the research. I always thought the visual changes were a side effect of the associated hair growth changes, facial structure changes, and lifestyle factors that often come along with the people who use testosterone at levels above what’s needed to get toward the median of the range.

The numbers in this study preprint are close enough that I’d want to see more replication, but it would sugg […]