Does using testosterone help if you are over 50, and can it be dangerous?

Testosterone can indeed have measurable effects on the body in men over 50. A meta-analysis of 29 randomised studies involving men with an average age of 64 shows that testosterone reduces fat mass by an average of 1.6 kg (roughly 6% of starting weight) while simultaneously increasing lean mass, a measure of muscle mass, by an average of 1.6 kg as well. The effect on muscle strength itself, however, is variable and has not been convincingly demonstrated statistically. Bone density in the lumbar spine improves by an average of 3.7%, but no demonstrable effect has been found at the hip.

For men who have both low testosterone and a low libido, the sexual benefits are more clearly supported. In a large American study (the TRAVERSE study, involving more than 5,000 men aged 45 to 80), testosterone gel significantly improved sexual activity, desire, and general complaints such as fatigue and mood problems compared with a placebo. This effect lasted for at least two years. Erectile problems, however, were not significantly improved.

The picture regarding the heart is nuanced. In the TRAVERSE study there was no difference in major cardiac events such as heart attacks, strokes, or heart-related deaths between the testosterone and placebo groups (7.0% versus 7.3%). The long-held concern that testosterone directly damages the heart does not appear to be confirmed for men who already had an elevated risk. However, the study did find more cases of atrial fibrillation (an irregular heartbeat), acute kidney failure, and pulmonary embolism in the testosterone group. These are serious side effects that should not be ignored.

There are also nuances regarding the prostate. In the TRAVERSE study there was no statistically significant difference in the number of prostate cancer diagnoses between the testosterone and placebo groups. Men who already had an elevated risk of prostate cancer were excluded from participation beforehand. PSA levels (a blood marker for prostate activity) did rise more in the testosterone group. Regular monitoring of PSA is therefore important during use. A notable finding that is not yet well understood is that the testosterone group in TRAVERSE had more clinical bone fractures, even though bone density in the spine increased.

Furthermore, testosterone modestly lowers total cholesterol (by an average of 0.23 mmol/l), particularly in men with low baseline values. HDL cholesterol, the protective cholesterol, may decline slightly, but this is mainly relevant for men who already had higher testosterone levels at the start.

An important caveat concerns who actually benefits. Testosterone is intended for men with a demonstrated disorder of hormone regulation, classically called hypogonadism. In men whose testosterone declines solely due to ageing or excess weight, there is no recognised indication and the scientific justification for treatment is still insufficient. Although observational studies show that low testosterone levels are associated with higher rates of diabetes, dementia, and premature death, this does not mean that raising testosterone also reduces those risks. The use of testosterone in older men has risen sharply in recent years, but the scientific basis for broad preventive use is currently lacking.