Testosterone is made overnight. Every hour of sleep you cut shows up in your bloodwork the next morning, and skipping a night completely shows up a lot. Here's what the large studies show about sleep and testosterone, how the daily cycle puts those drops in context, which supplements have the evidence, and how your genes change the picture.
Why testosterone is worth protecting
Testosterone helps you build and keep muscle, maintain bone density, produce red blood cells and drive libido, and it plays into energy and mood. In men, low testosterone is associated with cardiovascular disease, osteoporosis and higher mortality. Women produce testosterone too, from the ovaries and adrenal glands, in much smaller amounts, and it supports the same things: muscle, bone and sex drive.
Why it matters for women
For women the goal is balance rather than more. Too little affects sexual wellbeing: a meta-analysis of 36 randomised trials covering 8,480 women found that testosterone treatment after menopause improved desire, arousal, pleasure and orgasm, and reduced sexual distress. Too much carries its own risks: in UK Biobank, a genetic study of 425,097 people found that genetically higher testosterone in women raised the risk of type 2 diabetes (37% higher odds per standard deviation) and polycystic ovary syndrome (51% higher), while in men higher testosterone lowered type 2 diabetes risk.
Sleep drives the daily cycle
In younger men, testosterone rises during sleep, is highest in the early morning and falls across the day to an evening low. The night builds the morning high, and the rest of the day runs down from it. In a study of 2,569 men, readings taken at 7–9am averaged 207 ng/dl higher than readings taken between 9am and 2pm in men under 40, and 149 ng/dl higher at 40–44; by 45 the gap was gone.
What losing sleep does
Shorten the night and you shorten the stretch that builds the morning high.
In the US National Health and Nutrition Examination Survey (NHANES), researchers looked at 2,295 men aged 16–80. After adjusting for age and body mass index, each hour of lost sleep was associated with about 5.85 ng/dl lower testosterone. Age and BMI also mattered: testosterone fell about 0.5 ng/dl per year of age and about 6.2 ng/dl per BMI point.
The effect of a full night without sleep is much larger. A 2021 meta-analysis of 18 controlled trials found that 24 hours of total sleep deprivation significantly lowered men's testosterone, and 40–48 hours lowered it further. In the same analysis, a few nights of partial sleep restriction did not produce a significant drop on its own, which fits the NHANES picture: each lost hour costs a little, and skipping a night costs a lot.
The relationship isn't identical for everyone. A larger NHANES analysis of 8,748 men and women found the link between sleep length and testosterone varied by age and sex, with very long sleep also tied to low testosterone in middle-aged men and women. For women aged 41–64 the pattern was J-shaped: both short and very long sleep were linked with low testosterone. The sweet spot is a consistent, full night, not as much sleep as possible.
Put that on the daily curve: lost sleep lowers the morning peak, and because the rest of the day slides down from there, you spend the afternoon and evening running lower too.
Three ingredients with the evidence
Sleep is the main lever, but a few ingredients have held up in pooled trials for testosterone, sleep or both. These are the three with the strongest data.
| Ingredient | Helps with | What the pooled trials found |
|---|---|---|
| Ashwagandha | Testosterone and sleep | Across 23 randomised trials and 1,706 people, it raised men's testosterone by about 57 ng/dl and lowered cortisol, with no change in women's testosterone. A separate meta-analysis of 5 trials (400 adults) found improved sleep, most clearly at 600mg a day for 8 weeks or more. |
| Melatonin | Sleep | Across 19 trials and 1,683 people, it shortened the time to fall asleep by about 7 minutes, added about 8 minutes of total sleep and improved sleep quality. The benefit held with continued use. |
| Fenugreek | Testosterone | Across 7 trials and 449 people, mostly male athletes, it produced a small rise in total testosterone. The smallest and least certain effect of the three. |
One that didn't make the cut: vitamin D. A meta-analysis of 8 trials in men found no effect on total testosterone or SHBG. Worth taking if you're low for other reasons, but not for this.
Your genes set how much you get to use
Most testosterone in the blood is bound to sex hormone-binding globulin (SHBG). Only the unbound share is free to act on muscle and brain.
A genome-wide study of 8,938 men, replicated in another 5,491, found two independent SHBG variants linked to testosterone: rs12150660 and rs6258. Men with three or more risk copies across the two had 6.5 times the risk of low testosterone (under 300 ng/dl) compared with men carrying none. rs6258 also changes how tightly SHBG binds testosterone, which shifts the free fraction directly. That matters because many labs calculate free testosterone with a formula that assumes normal binding.
What to do with this
| Your SHBG result | Sleep target |
|---|---|
| 0 risk copies | 7+ hours. Sleep is your main lever. |
| 1–2 risk copies | 7–8 hours, with the same bedtime through the week. |
| 3+ risk copies | 8 hours. You start with less free testosterone to spare, so the night matters more. |
Seven hours is the minimum the American Academy of Sleep Medicine recommends for adults. For women, aim for a steady seven to eight: both shorter and much longer nights were tied to low testosterone in NHANES.
If you train
Hard session tomorrow? Protect tonight. An all-nighter is the clearest way to take testosterone down, so after a short night make it a lighter day and save the heavy work for after a full one.
Find your blend
Take the new 2-minute lifestyle quiz and get your bespoke supplement formula, built around how you sleep, train and live. Find your blend.
Want it built on your DNA too? Myoform reads all 3 billion base pairs of your genome with clinical-grade 30X whole genome sequencing, rs6258 and rs12150660 included. Get your genetic test.
Sources
- Welliver RC, et al. Validity of midday total testosterone levels in older men with erectile dysfunction. J Urol. 2014;192(1):165–169.
- Patel P, et al. Impaired sleep is associated with low testosterone in US adult males: results from NHANES. World J Urol. 2019;37(7):1449–1453.
- Su L, et al. Effect of partial and total sleep deprivation on serum testosterone in healthy males: a systematic review and meta-analysis. Sleep Med. 2021;88:267–273.
- Hernández-Pérez JG, et al. Association of sleep duration and quality with serum testosterone concentrations among men and women: NHANES 2011–2016. Andrology. 2024;12(3):518–526.
- Islam RM, et al. Safety and efficacy of testosterone for women: a systematic review and meta-analysis of randomised controlled trial data. Lancet Diabetes Endocrinol. 2019;7(10):754–766.
- Ruth KS, et al. Using human genetics to understand the disease impacts of testosterone in men and women. Nat Med. 2020;26(2):252–258.
- Fornalik M, et al. Hormonal modulation with Withania somnifera: systematic review and meta-analysis of randomized-controlled trials. Planta Med. 2026;92(8):790–805.
- Cheah KL, et al. Effect of Ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843.
- Ferracioli-Oda E, et al. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773.
- Isenmann E, et al. The anabolic effect of fenugreek: a systematic review with meta-analysis. Int J Sports Med. 2023;44(10):692–703.
- Hosseini Marnani E, et al. The effect of vitamin D supplementation on the androgenic profile in men: a systematic review and meta-analysis. Andrologia. 2019;51(9):e13343.
- Ohlsson C, et al. Genetic determinants of serum testosterone concentrations in men. PLoS Genet. 2011;7(10):e1002313.
The Decode is for education only and isn't medical advice.