Testosterone therapy: what the research shows

Part of our hormone therapy care. Here is what large clinical trials found, including the benefits and the risks your doctor monitors.

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For Florida residents only (adults 18+). No insurance needed.

Who TRT is for

Clinical guidelines recommend testosterone therapy only for men who have symptoms of low testosterone and low levels on at least two separate early-morning blood tests [1]. That is exactly how we diagnose it.

Common symptoms of low testosterone

  • Low sex drive
  • Low energy and motivation
  • Losing muscle or strength
  • Gaining fat, especially around the waist
  • Low mood or irritability

The evidence

What the research shows

Results from large randomized, placebo-controlled trials in men with low testosterone.

  • 7.0% vs 7.3%Heart safetyMajor heart events (heart attack, stroke or cardiovascular death) with testosterone vs placebo in 5,246 men aged 45 to 80 with heart disease or high heart risk. Testosterone did not increase the risk (TRAVERSE). [2]
  • 41.0% vs 27.5%Anemia correctedShare of men with anemia whose anemia resolved within 6 months on testosterone vs placebo, among 815 men with anemia (TRAVERSE anemia study). [5]
  • +10.8% vs +2.4%Spine bone strengthChange in estimated strength of spine bone after one year on testosterone vs placebo, in older men with low testosterone (Testosterone Trials, bone trial). [6]
  • 24 monthsSexual activityIn 1,161 men with low testosterone and low libido, testosterone increased sexual activity and desire compared with placebo, and the effect lasted through 24 months. Erectile function did not improve (TRAVERSE sexual function study). [4]
  • 59 trialsBody compositionA meta-analysis of 59 randomized trials found testosterone reduced fat mass and increased lean mass compared with control groups. [8]
  • 790 menLibido, erections and moodIn the Testosterone Trials, men 65 and older on testosterone had better sexual activity, sexual desire and erectile function than on placebo, and a small improvement in mood. Energy (vitality) did not improve. [3]

The risks, and how we watch for them

TRT is not right for everyone, and it needs monitoring. In the TRAVERSE trial, these were more common with testosterone than with placebo [2] [7]:

  • Atrial fibrillation (an irregular heart rhythm): 3.5% vs 2.4%
  • Acute kidney injury: 2.3% vs 1.5%
  • Blood clots in the lung: 0.9% vs 0.5%
  • Bone fractures: 3.50% vs 2.46% over about 3 years

Testosterone can also raise your red blood cell count and reduce sperm production, which matters if you want children. Guidelines recommend checking blood count and, depending on age, PSA during treatment [1].

How we monitor TRT

  • Two early-morning testosterone tests before any diagnosis
  • A baseline panel before any treatment, included in your plan
  • Follow-up labs for testosterone, blood count and PSA as guidelines recommend
  • Doses adjusted by your doctor as your results change

Read more about testosterone

Sources

  1. 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. View study (opens in a new tab)
  2. Lincoff AM, et al. Cardiovascular safety of testosterone-replacement therapy (TRAVERSE). N Engl J Med. 2023;389(2):107–117. View study (opens in a new tab)
  3. Snyder PJ, et al. Effects of testosterone treatment in older men (Testosterone Trials). N Engl J Med. 2016;374:611–624. View study (opens in a new tab)
  4. Pencina KM, et al. Effect of testosterone replacement therapy on sexual function and hypogonadal symptoms in men with hypogonadism (TRAVERSE). J Clin Endocrinol Metab. 2024. View study (opens in a new tab)
  5. Pencina KM, et al. Testosterone and anemia in men with hypogonadism (TRAVERSE anemia study). JAMA Netw Open. 2023;6(10):e2340030. View study (opens in a new tab)
  6. Snyder PJ, et al. Effect of testosterone treatment on volumetric bone density and strength in older men with low testosterone. JAMA Intern Med. 2017;177(4):471–479. View study (opens in a new tab)
  7. Snyder PJ, et al. Testosterone treatment and fractures in men with hypogonadism (TRAVERSE fracture study). N Engl J Med. 2024.
  8. Corona G, et al. Testosterone supplementation and body composition: results from a meta-analysis study. Eur J Endocrinol. 2016. View study (opens in a new tab)

Study results describe groups of people, not what any one person will experience. Treatment is decided by your physician after an assessment and labs.