Testosterone is a male sex hormone produced in the testes. It plays a vital role in developing features generally characteristic of males, such as facial hair, and preserving one’s sex drive, sperm production, and bone health. Millions of men worldwide grapple with low testosterone levels, also known as hypogonadism (1). Some men are born with low testosterone levels. Still, for others, it can be caused by testicle-related injuries, radiation treatment or surgery targeting the groin, chronic disease, specific medications, issues with the pituitary gland or hypothalamus, and aging (2). The standard treatment for low testosterone caused by problems with the pituitary gland, testes, or hypothalamus is testosterone replacement. However, testosterone is also being used to treat men who have low testosterone levels and are experiencing symptoms—such as reduced mobility, energy, and sexual function—that are not associated with a specific cause or diagnosis (3). In fact, this population is in large part responsible for the increasing use of testosterone treatment in some countries (3-7).
This then begs the question, what are the benefits and harms of treating men with low testosterone levels unrelated to a medical condition with testosterone? One systematic review produced to inform guidelines from the American College of Physicians on diagnosing and treating this issue provides some answers and things to think about (3).
What the research tells us
The review found that in men who have low testosterone levels without a related medical condition, testosterone—delivered through the skin or by injection into a muscle—may produce small improvements in sexual function, erectile function, and quality of life. These benefits are seen when men taking testosterone are compared to men taking a placebo. Areas that did not see enhancements include vitality/fatigue and physical function.
When it comes to potential harms, past research regarding the use of testosterone treatment has presented evidence that does not allow for concrete conclusions. The present review found that testosterone treatment in this population may not increase the risk for prostate cancer, cardiovascular events, or serious side effects. However, this seemingly positive result needs to be anchored in the fact that the individual studies included in the review did not have the ability to adequately assess important harms. Moreover, most studies did NOT include men with a history of heart disease, stroke, prostate cancer, or high prostate-specific antigen levels (3). Although not addressed in the review, the authors highlighted other potential concerns noted by the U.S. Food and Drug Administration. These include blood cancer, infertility, enlarged breast tissue, higher PSA levels and blood pressure, testicular shrinkage, and skin reactions from products that deliver testosterone via the skin (3;8). Additionally, the majority of the trials only followed participants for less than a year. This means that we do not know and cannot comment on the effectiveness and safety of testosterone treatment in the long-term. It is also worth noting that the certainty of the evidence for benefits and harms ranged from moderate to very low. As such, future research will likely have an impact on the findings discussed here (3).
What does this all mean? Ultimately, the small benefits that may come from testosterone use and the unclear long-term risks of harm need to be carefully weighed by those interested in this therapy and their health care team.
