This article has been medically reviewed by MD Niklas Marizy, Head of Medical at Adon Health.
Sleep is not a luxury; it is a physiological necessity. Especially for men between the ages of 25 and 60 who struggle with declining energy, reduced libido, or muscle loss, sleep can be a crucial lever for hormonal balance. This is because testosterone, the central hormone for vitality and male health, is produced primarily during sleep. This article highlights the scientifically proven link between sleep and testosterone and explains how sleep deprivation disrupts hormonal balance. We also explain how testosterone replacement therapy (TRT) can affect sleep quality.
What is testosterone and why is it so important?
Testosterone is the most important male sex hormone. It regulates, among other things, muscle building, bone density, fat distribution, libido, mood, and cognitive functions. It is produced mainly in the Leydig cells of the testes under the control of luteinizing hormone (LH) from the pituitary gland. Starting at age 30, testosterone levels drop by an average of about 1 to 2% per year (Jones, 2012). A deficiency can manifest itself, among other things, in chronic fatigue, depressive mood, loss of libido, and muscle loss (Ferreira & Mendonça, 2022, Shores et al., 2005).
The circadian rhythm: Why testosterone levels are highest in the morning
Testosterone is released rhythmically. In the morning, especially between 7 and 10 a.m., concentrations are highest (Vesper et al., 2010). This increase is linked to the circadian rhythm: At night, especially during the REM phases in the second half of the night, secretion reaches its peak (Leproult et al., 2011).
A disrupted circadian rhythm caused by shift work, jet lag, or irregular sleep patterns can severely disrupt hormonal balance.
How sleep affects testosterone production
Just one night of reduced or interrupted sleep can significantly lower testosterone levels the next day (Luboshitzky et al., 2001). A study by the University of Chicago showed that only five hours of sleep per night for one week reduced testosterone levels in healthy men by 10 to 15% (Leproult et al., 2011).
The available evidence in older men also confirms this link: Less than six hours of sleep per night is associated with a significantly higher risk of testosterone deficiency (Zhou et al., 2023).
REM sleep: The hormonally active phase
REM sleep is crucial for testosterone synthesis. During this phase, testosterone secretion increases sharply, especially during uninterrupted sleep (Luboshitzky et al., 2001). Those who wake up frequently at night, for example due to stress or sleep apnea, lose valuable REM time and thus important testosterone production.
Additionally, it has been shown that men with a high proportion of REM sleep were significantly more productive and resistant to stress during the day—an indirect effect of hormonal balance.
What happens during sleep deprivation?
- Elevated cortisol levels: Sleep deprivation leads to an increase in the stress hormone cortisol. This acts antagonistically to testosterone and directly inhibits its production through various hormonal axes (Wittert, 2014). Learn more about stress and testosterone in this blog post: Stress Management – Staying Healthy and Productive as a Man
- Reduction of LH and GnRH: Sleep deprivation impairs the secretion of LH and GnRH, which are essential for testosterone production (Anaissie et al., 2017).
- Increased risk of metabolic disorders: Chronic sleep deprivation promotes insulin resistance, weight gain, and fat accumulation—all factors that further lower testosterone levels.
- Increase in psychological symptoms: Men with testosterone deficiency due to sleep deficit often complain of lack of motivation, irritability, and depressive mood.
The vicious cycle: Testosterone deficiency worsens sleep
- Disrupted sleep architecture: Low testosterone levels lead to fewer deep sleep and REM phases. The result is unrefreshing sleep and daily exhaustion (McBride et al., 2016).
- Increased frequency of waking: Men with hypogonadism wake up more frequently at night. This reduces total sleep time and interrupts hormonal regeneration (McBride et al., 2016).
- Increase in sleep disorders: Low testosterone is associated with a higher prevalence of falling asleep and staying asleep problems. Targeted treatment of the hormone deficiency can provide relief here (Shlykova et al., 2020).
Sleep apnea: The hidden testosterone thief
- Reduction of REM time: Sleep apnea interrupts REM sleep and leads to a measurable decline in testosterone levels. Hormonal regeneration is severely impaired.
- Increased risk of testosterone deficiency: Men with untreated sleep apnea often have significantly lower testosterone levels than healthy sleepers (Gambineri et al., 2003).
- Important screening measure: Before starting TRT, screening for sleep apnea is recommended to minimize risks.
TRT and sleep: What does the research say?
- Improved REM phases: Studies show that medically supervised TRT can improve the duration and quality of REM sleep. Hypogonadal men benefit particularly from this (Barrett-Connor et al., 2008).
- Increased sleep efficiency: TRT can shorten sleep onset time and increase sleep efficiency. Many patients report more restorative and deeper sleep (Barrett-Connor et al., 2008).
- Caution with overdose: If testosterone is taken in too high doses, e.g., for doping, it can lead to sleep disorders and central sleep apnea. Medically supervised TRT avoids such risks (Liu et al., 2003).
Recommendations for action: How to optimize your sleep, and thus your testosterone levels
- Consistent sleep schedule: Go to bed at the same time every day, including weekends. A stable circadian rhythm promotes natural testosterone production (Vesper et al., 2010).
- Avoid blue light: Reduce screen time at least one hour before bedtime. Blue light inhibits melatonin production, which helps you fall asleep faster (Leproult et al., 2011).
- Create an optimal sleep environment: Ensure darkness, quiet, and a room temperature between 16 and 18 °C (Luboshitzky et al., 1999).
- Avoid evening stimuli: No intense exercise or heavy meals before bedtime (Leproult et al., 2011).
- Stress reduction: Mindfulness training can lower cortisol and improve sleep quality (Wittert, 2014).
- Substance abstinence: Avoid alcohol, nicotine, and caffeine (McBride et al., 2016).
- Ensure micronutrients: Zinc and magnesium support sleep and testosterone production (Davis et al., 2015).
- Fresh air and daylight: Morning sunlight improves melatonin regulation (Vesper et al., 2010).
🎧 Chief physician and sleep expert Dr. Martin Schlott gives tips on sleep in our men's health podcast. Click here for the episode.
Conclusion
Sleep is the foundation of male health and a key to natural testosterone production. Those who regularly sleep poorly risk hormonal imbalances with far-reaching consequences: loss of libido, muscle weakness, mental exhaustion. At the same time, a testosterone deficiency can negatively affect sleep.
The good news: Even small changes in everyday life—better sleep, less stress, targeted exercise—can achieve major hormonal effects. And: An individually tailored testosterone therapy under medical supervision can not only alleviate the symptoms of a deficiency but also improve sleep, provided all factors have been carefully assessed.
