Low testosterone – popularly known as ‘low T’ – may have a deadly association.
A recent systematic review has found that men with very low levels of this crucial sex hormone have a higher risk of developing and dying from cancer.
The research, published in the journal Lancet Healthy Longevity, analyzed long-term data from more than 26,000 men in Australia, the United States, and Europe.
“What we saw was that if a man had low testosterone levels – in the lowest one-fifth compared to the highest one-fifth of the range – their subsequent risk of dying from cancer was higher, even after allowing for age and other health-related factors,” explains senior author and endocrinologist Bu Yeap from The University of Western Australia.
Specifically, men with the lowest testosterone levels had an 18 percent higher relative risk of dying from any cancer.
But testosterone was not alone. Three other hormones were also linked to cancer in the study.
Men with the lowest levels of dihydrotestosterone (DHT), a potent hormone derived from testosterone, had a 21 percent higher relative risk of cancer death.
What’s more, men with the lowest levels of sex hormone-binding globulin (SHBG) had a 28 percent higher relative risk of prostate cancer, and those with the lowest levels of luteinizing hormone had a 45 percent higher risk.
SHBG helps carry testosterone in the bloodstream and ultimately determines how much ‘free’ testosterone is up for grabs.
Luteinizing hormone, meanwhile, is produced by the pituitary gland in the brain, and it stimulates testosterone production.
Interestingly, testosterone levels were not linked to prostate cancer.
“Since reducing testosterone levels is a treatment for prostate cancer there’s always been a question of whether the amount of testosterone your own body makes relates to your risk of prostate cancer but based on our findings there’s no evidence they are related,” says Yeap.
Testosterone is a crucial hormone in the male body, produced by the testes and the adrenal glands. It is involved in everything from sexual function and muscle mass to bone health and metabolism.
But while it’s completely normal for concentrations of testosterone to decrease with age, especially low levels may be a marker of poor health.
In the current review, when baseline testosterone was below 8.6 nmol/L, the subsequent risk of dying from cancer started increasing.
Today, ‘low T’ has become a scapegoat for practically everything that can go wrong in the male body.
But while low levels of this hormone are associated with numerous negative health outcomes in aging men, that does not mean testosterone is necessarily the cause, or that replacing this hormone can help.
Online influencers and a booming industry for testosterone replacement therapy have picked up that narrative and run far beyond the science.
In 2023, for instance, a large randomized trial followed more than 5,000 men with low testosterone for several years.
It found that testosterone replacement therapy did not significantly change their prostate cancer risk.
“While we’ve shown low levels are associated with increased risk, we haven’t got any evidence yet that actually giving men testosterone will reduce that risk,” says Yeap.
Instead, Yeap explains, the findings suggest that low testosterone could be a biomarker of poor health, “so it’s possible that looking at testosterone levels could help us identify men who might do poorly if they get cancer down the track.”
Previous studies that have investigated testosterone’s relationship to cancer and cancer mortality have been mixed, with some finding no association.
But this new review relies on research that used mass spectrometry to measure hormone levels, which is more accurate.
It also considers hormones other than testosterone but that are closely associated.
“What we would say to men is if they are found for whatever reason to be low in testosterone, it’s important to go to the doctor for a full checkup,” concludes Yeap.
“It may not show any sign of testicular disease, but it might show other health issues or risk factors they need to address.”
The research has been published in The Lancet Healthy Longevity.
This article was fact-checked by Rebecca Dyer and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.