Sleep and Testosterone: What the Evidence Shows | Men's Health Atlas
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Sleep Guide

Sleep and Testosterone: What the Evidence Shows

Last updated: October 13, 2026

Short sleep lowers testosterone, and sleep apnea and low testosterone often show up together. But the story most men hear, that fixing your sleep will fix your testosterone, goes further than the evidence. Here is what has actually been shown, and what to do with it.

The short answer

The daily rhythm

Testosterone isn't released at a steady rate. In men with a typical sleep pattern it peaks somewhere around 3 to 8 a.m. and drifts lower through the day. That is why the AUA recommends morning blood draws for diagnosing low testosterone, and why a result taken later in the day can look lower than the same man's morning level. The AUA also notes that acute illness can artificially lower results, by about 10% on average, which is another reason a single low value should be repeated. See getting accurate draws.

Our Sleep, Explained guide covers the body-clock basics.

What short sleep does

The best-known experiment is small but striking. In a 2011 study, 10 healthy men with an average age of 24 first slept about 9 hours a night, then spent 8 nights limited to 5 hours in bed (about 4 hours 48 minutes of actual sleep). Across the waking day, their testosterone was about 10% lower (16.5 versus 18.4 nmol/L), and about 13% lower in the afternoon and evening. Their vigor scores fell steadily, from 28 after the first restricted night to 19 after the seventh. Cortisol, a stress hormone that can suppress testosterone, didn't change, so it didn't explain the drop.

What it doesn't show. The authors called it a small convenience sample: ten young men, one week, in a lab. It doesn't tell us what years of mildly short sleep do in a 50-year-old, or whether the drop is large enough to cause symptoms. The authors also noted that the symptoms of low testosterone overlap heavily with the effects of sleep deprivation (low energy, low libido, poor concentration, sleepiness), and called for more research on whether sleep should be part of evaluating testosterone deficiency. That overlap is a good reason to look at your sleep before assuming a hormone problem. See which symptoms actually track with low T.

Sleep apnea and testosterone

The two clearly overlap. A September 2026 meta-analysis found lower testosterone in men with obstructive sleep apnea (roughly 7 to 9 nmol/L) than in men with shift-work sleep disorder (about 20 nmol/L), along with lower erectile function scores, though the studies varied enormously (heterogeneity of 97%). We covered it in our October 13 briefing.

But treating apnea hasn't been shown to raise testosterone. That is the key point many sources skip.

  • ?Pooled CPAP studies. A 2019 meta-analysis of 12 studies (10 prospective cohorts and 2 randomized trials, 388 men with OSA) found no significant change in total testosterone with CPAP (mean difference 1.08, 95% CI -0.48 to 2.64), and no significant change in LH, FSH, SHBG, free testosterone, or prolactin. The authors concluded the review does not support a direct link between OSA and testosterone.
  • ?A trial substudy in men with type 2 diabetes. Among 27 men who completed 3 months of CPAP, total and free testosterone didn't change significantly, though sleepiness improved.
  • ?The reverse experiment. In a 2026 report pooling two randomized trials (70 people with OSA), stopping CPAP for two weeks produced no significant change in testosterone, LH, or FSH.

These studies are short and usually small, and the abstracts we read don't report how consistently men used CPAP, so they can't rule out a benefit in particular men. One plausible explanation of the pattern is that apnea and low testosterone share a cause, with excess weight the leading candidate (next section), rather than apnea itself being the main thing suppressing testosterone. That is an interpretation, not something these studies prove.

CPAP is still worth it for what it does fix. In a 12-week trial of 61 men with both sleep apnea and ED, CPAP didn't change the overall erectile function score, but it increased sleep-related erections and overall sexual satisfaction, and men who used it consistently saw better erectile function (that last comparison isn't randomized, so treat it cautiously). It also treats sleepiness and other effects of apnea. See sleep apnea in men and ED and low testosterone.

The weight factor

Two kinds of evidence point at body weight:

  • A genetic study. Using a design that reduces confounding (Mendelian randomization) in 7,446 men from five European cohorts, researchers estimated that each standard-deviation increase in BMI lowers testosterone by about a quarter of a standard deviation. They estimated that moving from a BMI of 30 to 25 would correspond to roughly a 13% rise in testosterone.
  • Weight-loss studies. A 2013 meta-analysis of 24 studies found total testosterone rose after weight loss, by more after bariatric surgery than after a low-calorie diet (rises of 8.73 and 2.87 in the review's units, which the abstract doesn't state). The more weight men lost, the bigger the rise, and the effect was larger in younger men without diabetes who had more severe obesity.

Because sleep apnea is also driven by weight, this likely explains much of why apnea and low testosterone appear together. It also means that for a man who is overweight, weight loss may help his sleep apnea, his testosterone, and his blood pressure at once. See blood sugar and metabolic health and fitness.

If you're on, or considering, TRT

The relationship also runs the other way. In a randomized trial of 67 obese men with severe sleep apnea, a testosterone injection worsened measures of low blood oxygen during sleep after 7 weeks compared with placebo, though by 18 weeks the difference was no longer significant. It was a small, short study, but it's the reason guidelines list untreated severe sleep apnea as a "proceed with caution" condition. Read more in TRT side effects: sleep apnea.

Practically: get screened for apnea before starting testosterone, and tell your prescriber if you develop new or louder snoring, or growing daytime tiredness after you start. A provider that never asks about your sleep is not doing its homework; see how we score providers.

What to do

  1. Get your testosterone tested properly. A morning blood draw, repeated if it's low. See getting tested.
  2. Screen for sleep apnea if you snore, wake unrefreshed, or are very sleepy. Try the STOP-BANG screener, then ask about a sleep test. Sleeping pills can make untreated apnea worse; see sleep aids, graded.
  3. Give your sleep a fair trial. A consistent schedule and enough hours is cheap and helps energy and mood whatever your testosterone does. See Sleep, Explained.
  4. If you're carrying extra weight, treat that as part of the plan. It's the lever with the strongest evidence behind it.
  5. Don't expect sleep alone to normalize a truly low level. If testosterone is low on repeat testing and you have symptoms, that is a conversation to have with a doctor. See low T symptoms and diagnosis.

Sources

  1. Leproult R, Van Cauter E. Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA. 2011;305(21):2173-2174. PubMed
  2. Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and management of testosterone deficiency: AUA guideline. J Urol. 2018;200(2):423-432 (statement 2 discussion on timing and illness). American Urological Association
  3. Almurayyi M, Alshahrani ST, Alshardi WI, et al. Sleep disorders and male sexual dysfunction: a meta-analysis of hormonal and erectile outcomes. Arch Ital Urol Androl. 2026;98(3). PubMed
  4. Cignarelli A, Castellana M, Castellana G, et al. Effects of CPAP on testosterone levels in patients with obstructive sleep apnea: a meta-analysis study. Front Endocrinol. 2019;10:551. PubMed
  5. Knapp A, Myhill PC, Davis WA, et al. Effect of continuous positive airway pressure therapy on sexual function and serum testosterone in males with type 2 diabetes and obstructive sleep apnoea. Clin Endocrinol. 2014;81(2):254-258. PubMed
  6. Grewe FA, Thiel S, Haile SR, et al. Effects of CPAP withdrawal on sex hormone levels in patients with obstructive sleep apnoea: data from two randomised, controlled trials. Sleep Med X. 2026;12:100201. PubMed
  7. Melehan KL, Hoyos CM, Hamilton GS, et al. Randomized trial of CPAP and vardenafil on erectile and arterial function in men with obstructive sleep apnea and erectile dysfunction. J Clin Endocrinol Metab. 2018;103(4):1601-1611. PubMed
  8. Eriksson J, Haring R, et al. Causal relationship between obesity and serum testosterone status in men: a bi-directional Mendelian randomization analysis. PLoS One. 2017;12(4):e0176277. PubMed
  9. Corona G, Rastrelli G, Monami M, et al. Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis. Eur J Endocrinol. 2013;168(6):829-843. PubMed
  10. Hoyos CM, Killick R, Yee BJ, et al. Effects of testosterone therapy on sleep and breathing in obese men with severe obstructive sleep apnoea: a randomized placebo-controlled trial. Clin Endocrinol. 2012;77(4):599-607. PubMed

Medical disclaimer: This page is for general education only and is not medical advice. Persistent sleep problems, loud snoring, or excessive daytime sleepiness should be evaluated by a licensed physician.