I am 65. Been on Dr. prescribed TRT for over 25 years. Studies like the one below point to low T levels leading to shorter life spans. But from other studies it seems that high normal levels may equate with higher prostate cancer risk. I have not really deep dived to see where the sweet spot for T levels are in a while. Years ago when i looked it seemed that most killer diseases were less likely to happen with men in the upper 1/3 of the normal range. So while prostate cancer may be higher risk other killer diseases that happen suddenly would be lower. So high normal may not be the best for everything. Like most things it seems a person needs to find the balance they think is best for themselves. As a side note my PSA over the decades has gone from .4 to .7, with the top of the range at 4.0
www.health.harvard.edu

Low testosterone levels linked to shorter life span - Harvard Health
In a 2024 study of men ages 49 to 76, low levels of testosterone were associated with higher rates of death from any cause and specifically deaths from cardiovascular causes, such as heart attack, ...
