Does Lack of Sleep Lower Testosterone? What Sleep Loss Studies Show in Men Over 40

Lack of sleep does lower testosterone, but the size of the drop depends on how much sleep is lost. A week of 5-hour nights cut daytime testosterone by 10% to 15% in young men, a full night awake lowered it reliably across 18 studies, and men aged 60 to 80 showed the clearest losses.

Does lack of sleep lower testosterone? Yes. Cutting sleep short lowers testosterone, and a full night without sleep lowers it more reliably than a few short nights. In a University of Chicago study published in JAMA in 2011, a week of 5-hour nights lowered daytime testosterone by 10% to 15% in healthy young men. A 2021 meta-analysis of 18 studies found that a full night or more without sleep clearly reduced testosterone, while short spells of partial sleep loss did not show a consistent effect.

The link between lack of sleep and testosterone matters more after 40, because the nightly testosterone rise already gets weaker with age. This guide covers why testosterone depends on sleep, what the restriction and deprivation studies measured, why men over 40 may be more sensitive, and how much sleep the evidence supports. Every figure comes from studies opened and checked for this article.

Testosterone depends on sleep because the testes release much of their daily output overnight, in a rise that is tied to the sleep cycle rather than to the clock alone. Leproult and Van Cauter noted in their 2011 JAMA paper that the majority of the daily testosterone release in men occurs during sleep. That is why morning blood tests usually show a man's highest reading of the day.

The nightly testosterone rise is linked to REM sleep, the dreaming stage. Luboshitzky and colleagues tested this in 10 men in the Journal of Clinical Endocrinology and Metabolism in 2001, using a schedule that broke sleep into 7-minute attempts. Fragmented sleep delayed the testosterone rise from 22:35 to 03:24 on average, and a nocturnal rise appeared only in the 4 of 10 men who reached REM sleep. Average levels across the night were similar, so broken sleep shifted the timing more than the total in that small study.

A week of 5-hour nights lowered daytime testosterone by 10% to 15% in the best-known sleep restriction study. Leproult and Van Cauter brought 10 healthy men with a mean age of 24.3 into the University of Chicago sleep lab for 11 days. The men first slept 3 nights with 10-hour bedtimes, then 8 nights with 5-hour bedtimes. Measured sleep fell from 8 hours 55 minutes to 4 hours 48 minutes a night.

Between 8 AM and 10 PM, average testosterone was 16.5 nmol/L after the week of short sleep, against 18.4 nmol/L in the rested condition. The gap was widest between 2 PM and 10 PM, at 15.5 versus 17.9 nmol/L. Each short night cost the men 1 hour 3 minutes of REM sleep, and their vigor scores fell from 28 to 19 over the week. Cortisol did not rise, so the testosterone drop was not explained by a stress hormone response.

To put the result in context, Leproult and Van Cauter compared it with aging. Normal aging lowers testosterone by 1% to 2% per year, so a single week of 5-hour nights produced a drop several times larger than a typical year of aging in that sample. The authors also pointed out that 5-hour nights are a condition experienced by at least 15% of the US working population. The study was small and the men were young, so it shows that the effect exists rather than how large it is for every man.

Yes. Pooled data show that a full night or more without sleep lowers testosterone consistently, while short-term partial sleep loss has a smaller and less certain effect. Su and colleagues combined 18 studies involving 252 men in Sleep Medicine in 2021. Short-term partial sleep deprivation produced a standardized mean difference of -0.22, which was not statistically significant. Total sleep deprivation produced a difference of -0.64, a moderate and clearly significant drop.

The longer the time awake, the larger the effect looked. After 24 hours without sleep the standardized difference was -0.67, and after 40-48 hours it was -0.74. A standardized mean difference measures the size of an effect relative to the natural spread between people, so it does not translate directly into ng/dL, but values of this size are generally read as a moderate effect.

The meta-analysis result on partial sleep loss does not mean short nights are harmless. The meta-analysis abstract does not report how long the partial-deprivation studies ran, and the Leproult study suggests the effect can build over a week of short nights. A fair reading is that one short night is unlikely to move testosterone much, while repeated short nights and all-nighters are where the measurable losses appear.

The evidence points that way. In a randomized crossover study published in Sleep in 2020, Liu and colleagues kept 35 healthy men awake all night or let them sleep from 10 pm to 6 am, sampling blood every 10 minutes. Seventeen men were aged 18-30 and 18 were aged 60-80. A night without sleep reduced 24-h testosterone secretion, including mean levels and pulse frequency, and these effects were most apparent in older men.

The Liu team found the drop happened without a detectable change in LH, the pituitary signal that drives testosterone production, which suggests the testes themselves responded less. Older men also showed higher afternoon cortisol after the sleepless night. The study looked at a single night of total deprivation, so it does not show how older men respond to a week of shorter sleep.

Middle-aged men also start from a weaker nightly rhythm. Luboshitzky and colleagues compared seven healthy men with a mean age of 46.6 against six young men with a mean age of 23.9 in the Journal of Clinical Endocrinology and Metabolism in 2003, drawing blood every 15 minutes overnight with sleep recordings. The middle-aged men had a lower mean nighttime testosterone and fewer testosterone pulses, and in young men the testosterone rise came 90 min before the first REM episode, a link that was not seen in the middle-aged men.

In one small study, older men who slept less at night had lower morning testosterone. Penev studied 12 healthy men aged 64 to 74 at the University of Chicago, published in Sleep in 2007. Nighttime sleep measured in the lab tracked closely with sleep at home recorded by wrist monitors over 6-9 days, with a correlation of r = 0.842. The amount of nighttime sleep was an independent predictor of both morning total and free testosterone.

Large surveys give a messier picture. Hernández-Pérez and colleagues analyzed 8748 adults from NHANES 2011-2016 in Andrology in 2024. Among men aged 20-40, sleeping 6 h or less was linked to higher testosterone, and among men aged 41-64, those who reported longer sleep were more likely to have low testosterone. Sleep quality showed no association. Self-reported sleep in a single survey cannot show cause and effect, and long sleep can itself be a marker of poor health, so these findings sit alongside the lab studies rather than overturning them.

No trial has set a sleep target specifically for testosterone, so the best guide is the general adult recommendation. The CDC recommends 7 or more hours for adults aged 18-60, 7-9 hours for ages 61-64, and 7-8 hours for adults 65 and older. The restriction study above used 5-hour bedtimes, well below that range, and the clearest testosterone losses in the research come from nights far short of 7 hours or from no sleep at all.

The REM research adds a practical point. Because the testosterone rise is tied to REM sleep, and REM is concentrated later in the night, cutting the end of the night with an early alarm may cost more than the hours suggest. In the Leproult study, each 5-hour night removed 1 hour 3 minutes of REM sleep. Alcohol, late caffeine and untreated sleep apnea can also fragment sleep, and our guides on alcohol, caffeine and sleep apnea cover how each one affects testosterone.

Poor sleep the night before can plausibly push a testosterone result down, because the lab studies show lower levels after short or missed sleep. In the Liu study, a sleepless night reduced testosterone in the morning and afternoon in both young and older men. A man tested after a night shift, a red-eye flight or a week of 5-hour nights may get a reading that understates his usual level.

This is one reason a single low result is not enough for a diagnosis. If your result came back low after a stretch of poor sleep, it is reasonable to fix the sleep and repeat the test under normal conditions. Our guide to testing testosterone accurately explains the timing and fasting rules, and our article on normal testosterone levels at 40 covers what the reference ranges mean.

This article is for educational purposes only and is not medical advice. It does not diagnose, treat, cure or prevent any disease. Speak with a doctor about persistent sleep problems or symptoms of low testosterone.

• Leproult R, Van Cauter E. Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. JAMA, 2011. https://doi.org/10.1001/jama.2011.710
• Su L et al. Effect of partial and total sleep deprivation on serum testosterone in healthy males: a systematic review and meta-analysis. Sleep Medicine, 2021. https://doi.org/10.1016/j.sleep.2021.10.031
• Liu PY et al. Age and time-of-day differences in the hypothalamo-pituitary-testicular, and adrenal, response to total overnight sleep deprivation. Sleep, 2020. https://doi.org/10.1093/sleep/zsaa008
• Luboshitzky R et al. Middle-Aged Men Secrete Less Testosterone at Night Than Young Healthy Men. Journal of Clinical Endocrinology and Metabolism, 2003. https://doi.org/10.1210/jc.2002-021920
• Luboshitzky R et al. Disruption of the Nocturnal Testosterone Rhythm by Sleep Fragmentation in Normal Men. Journal of Clinical Endocrinology and Metabolism, 2001. https://doi.org/10.1210/jcem.86.3.7296
• Penev PD. Association Between Sleep and Morning Testosterone Levels in Older Men. Sleep, 2007. https://doi.org/10.1093/sleep/30.4.427
• Hernández-Pérez JG et al. Association of sleep duration and quality with serum testosterone concentrations among men and women: NHANES 2011-2016. Andrology, 2024. https://doi.org/10.1111/andr.13496
• Centers for Disease Control and Prevention. About Sleep. https://www.cdc.gov/sleep/about/index.html

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