Testosterone is a hormone that plays an important role in male health. It helps build muscles, increase energy, and support sexual function.
Sometimes, doctors prescribe testosterone supplements to men who have a condition called hypogonadism, where the body doesn’t make enough testosterone. These treatments can help improve strength, mood, and energy levels.
But now, new research from the University of Cambridge suggests that having too much testosterone in the blood could actually be harmful—especially for the heart.
The study, published in The Journal of Clinical Endocrinology & Metabolism, shows that high levels of testosterone may raise the risk of coronary artery disease in men. Coronary artery disease happens when the blood vessels that supply the heart become narrowed or blocked. This can lead to serious problems like heart attacks or heart failure.
In recent years, testosterone supplements have become more popular, not just for medical reasons, but also because many younger men believe these products can boost their physical performance and slow down aging.
Social media and advertising have played a big role in encouraging this trend. But scientists are concerned that not enough is known about the long-term effects of high testosterone levels, especially when the supplements are taken without a clear medical need.
To better understand the risks, researchers used a method called Mendelian randomization. This method uses genetic information to study how certain traits—like hormone levels—might affect the risk of disease. It helps scientists find out whether one thing really causes another, rather than just being linked by chance.
The team looked at genetic data from over 400,000 people in the UK Biobank and more than 1 million people in another large study called CARDIoGRAMplusC4D. They searched for genetic differences that lead to higher levels of testosterone in the blood and then checked to see if these people had a higher or lower chance of developing heart disease.
The results were clear: Men with genes that lead to higher testosterone levels had a 17% greater risk of getting coronary artery disease. To put that into context, the average man has about a 7.3% chance of developing this kind of heart disease over his lifetime.
But if testosterone levels are higher than normal, that risk can rise to 8.5%. The researchers believe that one reason for this increase is that testosterone can raise blood pressure, which puts more strain on the heart.
Interestingly, earlier studies that seemed to show the opposite—that low testosterone was linked to higher heart risk—may have been affected by other health problems like diabetes and obesity. People with these conditions often have lower testosterone and a higher risk of heart disease, which may have confused the results.
In this new study, there was no strong link found between testosterone and heart disease risk in women.
Emily Morbey, a Ph.D. student at the University of Cambridge and one of the lead researchers, said that more and more men are using testosterone supplements, often without medical advice.
She warned that while the hormone can be helpful when there’s a real medical reason to use it, taking it just to feel stronger or more energetic might actually increase the risk of heart problems.
Professor Ken Ong, one of the senior researchers, pointed out that in the U.S., health officials already warn people about the possible heart risks of using testosterone supplements. But in the U.K., there is no national guidance yet. He believes these new results show that such warnings are needed.
This study gives us a clearer picture of how testosterone affects the heart. It shows that while testosterone supplements can be helpful in certain cases, using them without medical need might do more harm than good.
The findings highlight the importance of understanding how our hormones affect our health and of being careful with supplements that can change those levels.
If you care about heart health, please read studies about top foods to love for a stronger heart, and why oranges may help fight obesity, diabetes, and heart disease.
For more health information, please see recent studies about simple guide to a 7-day diabetes meal plan, and why you should add black beans to your plate.
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