Few topics in men's health generate more confusion than testosterone. Social media is full of clinics promising that testosterone therapy will restore energy, build muscle, sharpen the mind and transform your life. What they are less enthusiastic about mentioning is the largest randomized trial ever conducted on the subject — and what it found.
The TRAVERSE trial: 5,246 men, one clear message
Published in the New England Journal of Medicine in 2023, the TRAVERSE trial randomized 5,246 men aged 45–80 with symptoms of hypogonadism, two fasting testosterone levels below 300 ng/dL and either existing cardiovascular disease or high cardiovascular risk to receive either testosterone gel or placebo. Mean follow-up was 33 months.
The results: TRAVERSE was designed to test safety, not benefit. Testosterone replacement did not increase major cardiovascular events such as heart attack and stroke (7.0% vs 7.3%) — but it did not reduce them either, and several serious adverse events occurred more often in the testosterone group:
- Atrial fibrillation: more frequent in the testosterone group
- Acute kidney injury: more frequent
- Pulmonary embolism: more frequent
These are not minor side effects. Atrial fibrillation is the most common cardiac arrhythmia and a major risk factor for stroke. Pulmonary embolism can be fatal. And these harms occurred in men who actually had low testosterone — not in men with normal levels being treated for lifestyle reasons.
When testosterone replacement is appropriate
This does not mean testosterone therapy is never warranted. It is — but only in a specific clinical context. The Endocrine Society guidelines are clear: testosterone replacement is indicated for men with both documented low testosterone on repeated morning measurements and clear clinical symptoms of hypogonadism (fatigue, loss of libido, erectile dysfunction, muscle wasting, depressed mood).
Both parts are required. Low testosterone without symptoms does not need treatment. Symptoms without confirmed low testosterone do not need testosterone — they need a different work-up.
And "low" means genuinely low — confirmed on repeated morning fasting draws against a reliable laboratory reference range (TRAVERSE used below 300 ng/dL), ideally confirmed with free testosterone or calculated bioavailable testosterone. A single measurement of 310 ng/dL in the afternoon is not a diagnosis.
A common pattern
Many men have been told their testosterone is "low" based on a single measurement, often taken in the afternoon (when testosterone is naturally at its lowest). Some are already on replacement therapy prescribed by wellness clinics without a proper work-up. If that sounds familiar, it is worth asking a physician to check whether the diagnosis was correct in the first place — and, if it was, whether the treatment is appropriate and being monitored safely.
The "optimization" trap
A growing industry of testosterone clinics markets "optimization" — treating men who have normal testosterone levels to push them higher. The theory is that more testosterone equals more energy, more muscle, more vitality. The evidence says otherwise.
In men with normal testosterone, there is no good evidence that supplementation improves health outcomes. What it does do is suppress the body's own testosterone production (the hypothalamic-pituitary-gonadal axis shuts down when external testosterone is supplied), which means that once started, stopping is difficult — natural production may not recover fully.
Add the TRAVERSE safety signals, and the risk-benefit balance of "optimization" in men with normal levels is clearly unfavorable. Testosterone at normal levels belongs in the same category as IV infusions and most supplements: interventions where the potential for harm exceeds the evidence of benefit (see also longevity science vs marketing).
What a proper work-up looks like
For men with genuine symptoms, a complete hormonal work-up includes SHBG, free testosterone, DHEA-S, prolactin and LH. It distinguishes primary hypogonadism (testicular failure) from secondary (pituitary) causes and rules out conditions that mimic low testosterone (thyroid dysfunction, depression, sleep apnea, medication effects).
If replacement therapy is genuinely indicated, it requires ongoing management and monitoring by your physician — including regular PSA and hematocrit checks, as recommended by the Endocrine Society, and attention to cardiovascular risk.
Questions to ask your doctor
- Was my testosterone measured in the morning, and more than once?
- Have free testosterone, SHBG and LH been checked to find the cause?
- Have other explanations for my symptoms — thyroid, sleep apnea, depression, medications — been ruled out?
References
- Lincoff AM, et al. Cardiovascular safety of testosterone-replacement therapy. N Engl J Med. 2023;389(2):107-117.
- Bhasin S, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744.
- Snyder PJ, et al. Effects of testosterone treatment in older men. N Engl J Med. 2016;374(7):611-624.
This article is general information and not individual medical advice. Decisions about tests and treatment belong in a conversation with your own physician.