Cutting sleep can bring testosterone down. How far, and for how long? We summarize the sleep restriction research and point to the habits that deserve your effort.
A 2011 JAMA study followed 10 healthy young men who slept fewer than five hours a night for a week. Their daytime testosterone fell by about 10 to 15%. Sleep apnea has also been tied to low testosterone, although excess weight accounts for much of that link. Getting seven or more hours of unbroken sleep, managing weight and treating sleep disorders will do far more than any supplement.
Sleep and testosterone are tightly connected. A large share of a man's daily testosterone output is tied to sleep, so shortening it can pull levels down. In the best-known experiment, a week of nights under five hours reduced daytime testosterone by about 10 to 15% in healthy young men.
The effect is real, but keep it in perspective. The study was small, the fall was moderate and levels remained within the normal range. The broader takeaway: ongoing short sleep, sleep apnea and the weight gain that often comes with them can all lower testosterone, and addressing them accomplishes more than a supplement can.
Most people cite work by Rachel Leproult and Eve Van Cauter at the University of Chicago, published in JAMA in 2011. Ten healthy, lean men averaging about 24 years old spent three nights in a sleep lab with up to 10 hours in bed. They then spent eight nights allowed only five hours in bed.
The University of Chicago's write-up of the study notes that testosterone usually declines about 1 to 2% a year as men age, making the drop similar to 10 to 15 years of aging. The comparison grabs attention, but it describes a short-term dip after one week and not a lasting change.
The authors themselves asked for more research, including on whether doctors should factor sleep into evaluating low testosterone.
Gary Wittert's 2014 review in Current Opinion in Endocrinology, Diabetes and Obesity concluded that the daily cycle of testosterone seems to depend on sleep itself and not only on the body clock. Going without sleep entirely lowers testosterone. Per the review, partial restriction seems to matter chiefly when it eats into the early part of the night.
Put simply, both the length and the continuity of your sleep can count. A very late bedtime, repeated waking or breathing interruptions all fragment the sleep that testosterone production depends on.
Causation can run in either direction. Low testosterone is itself tied to fatigue and low mood, which can worsen sleep. If you feel tired all the time, look at both sides with a doctor instead of assuming one causes the other. Our guide to low testosterone symptoms in men describes how proper testing is done.
Obstructive sleep apnea (OSA), in which the airway keeps collapsing during sleep, is common among men with low testosterone. The connection is less straightforward than it looks.
A 2019 meta-analysis in Frontiers in Endocrinology (Cignarelli and colleagues) combined 12 studies covering 388 men with OSA. CPAP, the standard breathing machine, produced no significant change in total testosterone, free testosterone or the hormones that regulate testosterone production. This was true whether men started low or normal, although men with low testosterone showed a non-significant trend toward improvement.
The meta-analysis and the Wittert review both identify obesity as a major driver. Once body weight or waist size is accounted for, the association between sleep-disordered breathing and testosterone gets weaker or vanishes. Wittert observes that weight loss tends to raise testosterone, whereas CPAP results are inconsistent.
That doesn't make sleep apnea unimportant. It ruins sleep quality and carries its own health risks. Loud snoring, gasping at night or heavy sleepiness in the daytime are good reasons to see a doctor, who can order a sleep study. Just don't count on a CPAP machine by itself to correct low testosterone.
Testosterone therapy and sleep apnea affect each other as well. Mayo Clinic includes worsening sleep apnea among the possible risks of testosterone therapy, one reason doctors ask about snoring and sleep before prescribing. Wittert's review indicates the effect is generally temporary, but raise it with your doctor anyway.
The CDC advises 7 or more hours of sleep a night for adults 18 to 60, 7 to 9 hours for ages 61 to 64, and 7 to 8 hours from 65 on. Its practical tips match what the testosterone research suggests:
A supplement can't make up for chronic short sleep. Some people take magnesium as part of a wind-down routine, and our guide to magnesium supplements covers forms, doses and where the evidence stops. Zinc affects testosterone mostly when your own levels are actually low, as our piece on the link between zinc and testosterone explains.
Ashwagandha is another common pick for stress and sleep. If it interests you, our article on when to take ashwagandha answers the timing questions. Check with your doctor before using any sleep supplement if you take sedatives, antidepressants, thyroid medicine or blood pressure medicine, or if you have a diagnosed sleep disorder.
In a small study of young men, a week of sleeping under five hours a night reduced daytime testosterone by about 10 to 15%. Sleep apnea is linked to low testosterone too, but excess weight explains much of the connection, and CPAP on its own doesn't appear to raise levels. The changes that count are seven or more hours of steady sleep, weight management and a check on any snoring. Supplements come a distant second.