Is Poor Sleep to Blame for Low Testosterone?

June is Men's Health Month and one of the most overlooked aspects to men's hormonal health is not food, stress, or age. It's sleep.

Man asleep in bed

How are sleep and testosterone connected?

Testosterone isn't just about libido or muscle mass (though it plays a role in both). It supports energy levels, mood, cognitive sharpness, bone density, and cardiovascular health. It's a hormone that does a lot of quiet, important work. 

Most of this work is done during your sleep. Approximately 70-90% of your daily testosterone is produced during sleep. It doesn't trickle in steadily throughout the day, it surges during the night. The rate of testosterone production peaks during the first REM cycle, about an hour into sleep, with circulating levels of testosterone at their highest in the early morning hours, when you wake up.

What does the research say about sleep and testosterone?

In a classic study from the University of Chicago, published in the Journal of the American Medical Association, researchers convinced healthy young men to sleep for just 5 hours a night for one week. The result? Testosterone levels dropped by around 15%. To put that into context, that's roughly equivalent to ageing 10-15 years in terms of hormonal decline.

More recently, research published in Reviews in Endocrine and Metabolic Disorders has highlighted another layer to this picture: short sleep duration and a diet high in ultra-processed foods appear to independently lower testosterone, and when combined, those effects may compound.

While most of us aren't living on five hours of sleep every night, many men are regularly getting less than the recommended 7-9 hours.

What are the signs that sleep might be affecting your hormonal health?

There's no single red flag, which is part of what can make this tricky. However, if you've been experiencing a cluster of the following, it's worth paying attention:

• Persistent fatigue, that doesn't lift even after a weekend lie-in

• Lower motivation or drive (feeling flat)

• Difficulty building or maintaining muscle, despite consistent exercise

• Changes in mood (including irritability or a low-level sense of blunting)

• Reduced libido

• Brain fog or difficulty concentrating

  
  

None of these in isolation means your testosterone is low. Life is complicated, and there are many possible contributing factors. If several of these resonate, sleep is a great place to start looking.

How much sleep do men actually need?

Most adults need between 7 and 9 hours of sleep per night. This scale can be shown as a bell curve, there are some people in the world who can genuinely function well on 7, whereas others need closer to 9.

The key isn't just duration. Regularity matters . A large UK study tracking over 60,000 adults found that people with the most consistent sleep schedules, going to bed and waking at roughly the same time each day, were significantly less likely to experience poor health outcomes compared to those with erratic patterns. In fact, consistency in sleep timing appeared to matter as much as, or even more than, total sleep duration.

Your body runs on a biological clock, your circadian rhythm, and testosterone release is tightly tied to it. When your sleep timings vary significantly night to night, that rhythm gets disrupted, and so does the hormonal cascade that follows.

Does diet play a role in testosterone production too?

Absolutely. While sleep is one of the most powerful drivers of testosterone production, diet matters too.

Emerging research suggests that diets high in ultra-processed foods are associated with lower testosterone levels, potentially through their effects on inflammation, insulin resistance, and metabolic health. 

What is particularly interesting is how diet and sleep interact: poor nutrition can disrupt sleep quality, while inadequate sleep often drives cravings for highly processed foods.

In other words, sleep and diet don't just influence testosterone independently, they can amplify each other's effects.

If you are looking to naturally improve your sleep, research suggests that what you eat matters. To improve your diet for sleep:

• Increase fibre intake (whole grains, legumes, vegetables)

• Eat a wider variety of plant foods

• Try to avoid large, late evening meals

  
  

Fibre-rich, plant-forward meals could be a small but meaningful step toward deeper, more restorative sleep.