Sleep Stages and Testosterone Production: When Your Body Actually Makes T

You probably know that sleep matters for testosterone. But understanding exactly whenduring the night testosterone rises, and what the research does and does not say about sleep stages, changes how you think about sleep. It is not just about logging hours, and it is not as simple as “REM makes testosterone.” This article is educational and not medical advice.

Sleep Architecture 101: The Four Stages

Every night, your brain cycles through distinct sleep stages in repeating cycles of roughly 90 minutes. A typical night includes four to six of these cycles, and the composition of each cycle shifts as the night progresses: deep sleep is more prominent early on, and REM sleep takes up more of each cycle later in the night. In healthy adults, stage N1 typically makes up about 2 to 5 percent of total sleep time, N2 about 45 to 55 percent, N3 about 15 to 25 percent, and REM about 20 to 25 percent.^[5]

Stage 1 (N1) is the light transition phase lasting only a few minutes. You are drifting off, and brain activity begins to slow.

Stage 2 (N2) is a deeper light sleep where heart rate drops and body temperature decreases. This is the largest share of the night. Sleep spindles and K-complexes appear on EEG.

Stage 3 (N3 or slow-wave sleep) is deep sleep, the stage most associated with physical restoration. It is also when growth hormone is preferentially released.

REM sleep is where the brain is highly active and vivid dreaming occurs. REM periods are shorter early in the night and longer toward morning.

When Testosterone Actually Rises

Testosterone follows a daily rhythm that peaks during sleep and reaches its lowest point in the late afternoon, with smaller pulses roughly every 90 minutes superimposed on top. The nighttime increase appears to depend on sleep itself rather than on the time of day, and a review of the sleep and testosterone literature concluded that it requires at least about 3 hours of sleep with a normal structure.^[3]

The best-known study of how this lines up with sleep stages sampled blood every 15 minutes overnight in six healthy young men while recording their sleep. Testosterone was lowest while the men were awake in the evening, began to rise on falling asleep, peaked at about the time of the first REM period, and then stayed at about the same level until waking. The rise began roughly 90 minutes before the first REM period, and it was slower in men whose first REM period came later. Notably, average nighttime testosterone did not correlate with the number of REM episodes.^[1]

That is a small study, so it should be read with caution. But it does not support the popular idea that REM sleep “produces” testosterone in large pulses or that the final REM-rich hours of sleep are responsible for most of it. What the research does support is simpler: testosterone rises with sleep, and chronically short or disrupted sleep can be associated with lower levels.

The Role of Deep Sleep: Growth Hormone

Deep slow-wave sleep is most closely tied to growth hormone rather than testosterone. For more than 30 years, growth hormone has been observed to be preferentially secreted during deep sleep, including at the start of the night.^[7] Growth hormone supports tissue repair and recovery, which is why deep sleep matters for people who train. We did not find direct human evidence that deep sleep amounts determine testosterone output, so we treat that link as plausible but unproven.

What Disrupts Sleep Architecture

Many common habits can reduce sleep quality without you realizing it. You might spend 7 hours in bed but get fragmented, lighter sleep. The research on how each of these habits affects testosterone specifically is limited, but each has well-documented effects on sleep itself.

Alcohol may help you fall asleep faster, but a review of studies in healthy volunteers found that it increases sleep disruption in the second half of the night, delays the first REM period, and at moderate and high doses lowers total REM sleep.^[8] Learn more about how alcohol relates to testosterone.

Evening light from screens can delay your body clock. In a controlled study, people who read on a light-emitting e-reader before bed took longer to fall asleep, had reduced melatonin secretion, and showed a later circadian clock than when they read a printed book.^[9]

Caffeine taken late in the day can cut into sleep. In one study, 400 mg of caffeine taken even 6 hours before bedtime significantly disturbed sleep and reduced total sleep time compared with placebo.^[10]

A warm bedroom matters too. A review of thermal environment and sleep found that heat exposure increases wakefulness and decreases slow-wave and REM sleep.^[11]

Sleep apnea fragments sleep, and it is a medical condition worth taking seriously on its own. Its relationship with testosterone is more complicated than often stated: a review found that obstructive sleep apnea appears to have no direct effect on testosterone after adjusting for age and obesity, and that weight loss raised testosterone more predictably than CPAP treatment.^[3] If you snore loudly, wake up gasping, or feel unusually sleepy during the day, see a doctor. Our guide on sleep apnea and testosterone has more detail.

How to Protect Your Sleep Quality

The goal is not to engineer exact sleep cycles, but to give yourself consistent, sufficient, uninterrupted sleep. Here is a practical, low-risk routine built on general sleep hygiene.

Using Sleep Tracking Wisely

Consumer wearables like the Oura Ring, WHOOP, Apple Watch, and Fitbit estimate time spent in each sleep stage. A laboratory comparison of seven consumer sleep trackers with polysomnography found they were good at detecting sleep (sensitivity of 0.93 or higher) but weaker at detecting wake (specificity 0.18 to 0.54), that their sleep stage estimates were inconsistent, and that they performed worse on nights of poor or disrupted sleep.^[12]

That means the most reliable things to track are the basics: how long you sleep, when you go to bed and wake up, and how rested you feel. Treat stage minutes as rough hints, and look at trends over weeks rather than single nights. Experiment with one change at a time, such as an earlier bedtime or a caffeine cutoff, and watch how your energy and consistency respond over a couple of weeks.

How Thrive Helps

Thrive is a wellness app that tracks your sleep habits alongside your other daily routines, helping you see how bedtime consistency, sleep duration, and evening habits relate to how you feel. It is a habit tracker and educational tool, not a medical device. Try Thrive free and build more consistent sleep habits.