Benefits of Testosterone Replacement Therapy for Men

Testosterone therapy is usually considered when a man has symptoms such as low libido, tiredness or loss of muscle, and blood tests show that his testosterone is low. Before starting, most men want to know what treatment will realistically change for them and what the trade-offs are.

Those questions have better answers than they did ten years ago. Several large placebo-controlled trials, including the Testosterone Trials in men over 65 and TRAVERSE in more than 5,000 men aged 45 to 80, have measured what testosterone does. Their results support some of the benefits commonly attributed to it and rule out others.

All of them come from men with confirmed low testosterone, and there is no good evidence that raising testosterone in men with normal levels brings the same benefits.

What testosterone improves

Sexual function shows the clearest benefit. In the Testosterone Trials, men treated for a year reported more sexual activity, more desire and better erections than men on placebo, and TRAVERSE found similar improvements across a wider age range. For many men, low libido is the symptom that responds most noticeably.

Body composition changes too. A meta-analysis of 59 randomized trials found that men on testosterone lost fat and gained lean mass while their weight stayed about the same, which is why the scale is a poor guide to progress. We cover this in more detail in Does Testosterone Therapy Cause Weight Gain?

The effect on mood is smaller. Men in the Testosterone Trials reported a modest improvement in mood and depressive symptoms, but testosterone is not a treatment for depression, and low mood has plenty of other causes worth checking.

Treatment also raised bone density and estimated bone strength in older men. It increased hemoglobin as well, and corrected anemia in some of the men who had it.

Where the results are mixed

Bone is the surprising one. Although density went up in the Testosterone Trials, men on testosterone in TRAVERSE had somewhat more fractures than men on placebo. The researchers did not expect this and have no clear explanation yet. For now, testosterone should not be thought of as a treatment for weak bones.

Blood sugar is less clear. In the Australian T4DM trial, men aged 50 to 74 with prediabetes or newly diagnosed type 2 diabetes joined a lifestyle program, and half of them also received testosterone. Two years later, fewer of the men on testosterone had type 2 diabetes. TRAVERSE, on the other hand, found that testosterone did not significantly slow the move from prediabetes to diabetes.

What it does not do

Several of the most advertised benefits did not show up in the trials. Testosterone did not improve energy or fatigue in the Vitality Trial, part of the Testosterone Trials. Men who had difficulty walking did not walk significantly farther after a year of treatment. In the Cognitive Function Trial, a year of testosterone did not improve memory or any other area of thinking.

The heart is often misdescribed. TRAVERSE showed that testosterone did not increase heart attacks or strokes in men with low levels, which matters for safety. It did not show that testosterone protects the heart.

The risks

Testosterone raises the red blood cell count, so hematocrit is checked before treatment and again a few months in. It lowers sperm production, which makes it a poor choice for men who want children soon. It can worsen sleep apnea, and men 40 and older should discuss prostate monitoring before they start. TRAVERSE also found more atrial fibrillation, pulmonary embolism and acute kidney injury in the testosterone group, on top of the fracture finding.

Getting evaluated at SaltMD

Treatment starts with a 30-minute consultation, in person in Atlanta or by video, about your symptoms and whether you plan to have children. Your clinician then orders a hormone panel, drawn at a lab near you or at our office, or reviews blood work you have had in the past 90 days. If the results confirm low testosterone and treatment makes sense for you, your prescription is filled by a partner pharmacy and shipped to you. Follow-up labs track your levels and hematocrit from there.

You can read more about how testosterone therapy works day to day or about TRT at SaltMD.

Sources

• Snyder PJ et al. Effects of testosterone treatment in older men. N Engl J Med. 2016;374(7):611-624.
• Resnick SM et al. Testosterone treatment and cognitive function in older men with low testosterone and age-associated memory impairment. JAMA. 2017;317(7):717-727. doi:10.1001/jama.2016.21044
• Snyder PJ et al. Effect of testosterone treatment on volumetric bone density and strength in older men with low testosterone: a controlled clinical trial. JAMA Intern Med. 2017;177(4):471-479. doi:10.1001/jamainternmed.2016.9539
• Roy CN et al. Association of testosterone levels with anemia in older men: a controlled clinical trial. JAMA Intern Med. 2017.
• Lincoff AM et al. Cardiovascular safety of testosterone-replacement therapy. N Engl J Med. 2023;389(2):107-117.
• Snyder PJ et al. Testosterone treatment and fractures in men with hypogonadism. N Engl J Med. 2024;390(3):203-211.
• Wittert G et al. Testosterone treatment to prevent or revert type 2 diabetes in men enrolled in a lifestyle programme (T4DM). Lancet Diabetes Endocrinol. 2021;9(1):32-45.
• Corona G et al. Testosterone supplementation and body composition: results from a meta-analysis study. Eur J Endocrinol. 2016;174:R99-R116. doi:10.1530/EJE-15-0262