A new study has provided fresh insights into the complex relationship between testosterone and biological ageing in men, suggesting that higher testosterone levels may not be the answer for men wanting to slow the ageing process.

“The findings have implications for the broader context of male ageing and argue against the concept of testosterone slowing biological ageing in men.”

Professor Bu Yeap, UWA Medical School

The research, published in the European Journal of Endocrinology, analysed data from 167,706 men aged 40-to-69 years who were part of the UK Biobank Study to investigate whether higher levels of testosterone were linked to longer telomeres, the protective caps at the end of our chromosomes.

The study’s senior author, Professor Bu Yeap from The University of Western Australia’s Medical School, said telomeres were repetitive DNA sequences at the ends of chromosomes, bound by specific proteins, that protected the genetic material within our cells from damage or degradation during cell division. 

“Telomeres are like the plastic tips at the ends of shoelaces that keep them from fraying and the length of telomeres act as a kind of ‘clock’ for cellular ageing and they shorten as we grow older,” Professor Yeap said.

“Given that shorter telomeres are a marker for biological age, we wanted to test the hypothesis that testosterone concentrations are associated with telomere length in middle-aged to older men.”

Telomeres play a critical role in maintaining the stability of our chromosomes, and they tend to shorten as we age or due to various environmental factors such as stress, unhealthy diet, or lack of physical activity.

Shorter telomeres have been linked to a higher risk of age-related diseases, such as cardiovascular disease, and have also been associated with a shorter lifespan.

The study, which used measurements of testosterone and sex-hormone-binding globulin  in the blood, and of telomere length from white blood cells, found that men with higher testosterone levels had shorter telomeres, indicating that testosterone does not appear to preserve telomere length.

“The findings have implications for the broader context of male ageing and argue against the concept of testosterone slowing biological ageing in men.” Professor Yeap said.

“Other factors, such as maintaining healthy lifestyle habits, may be more important for preserving telomere length and overall health in ageing men."