Obesity-driven muscle deterioration occurs when mitochondria, the energy-producing centers of your cells, stop working properly. Skeletal muscle requires constant energy, but when insulin resistance sets in, mitochondrial function declines and oxidative stress skyrockets.
As a result, your body loses its ability to efficiently generate energy, while inflammation and free radicals break down muscle fibers faster than they regenerate. Over time, this leads to muscle weakness, reduced endurance, and worsening glucose control, which fuels the very disease that caused the problem in the first place.
With metabolic disease on the rise, solutions that support mitochondrial health are more important than ever. New research published in Free Radical Biology and Medicine1 in February 2025 highlights an unexpected player in this process — melatonin. While this hormone is more commonly known as a sleep regulator, melatonin is also a key factor in preserving muscle function and optimizing energy metabolism at the cellular level.
How Melatonin Supports Muscle Health and Prevents Damage from ‘Diabesity’
The featured study, led by researchers from the University of Granada, Spain, looked at how melatonin influences muscle health in rats with both obesity and diabetes, a condition they referred to as “diabesity.” Researchers aimed to determine if melatonin prevents muscle loss by increasing energy production and improving muscle fibers. They focused on the vastus lateralis, a large leg muscle that helps with movement and stability. The researchers observed that melatonin:2
• Restores muscle fibers lost due to diabetes — After 12 weeks of melatonin supplementation, researchers observed that melatonin increased slow-twitch muscle fibers and reduced fast-twitch fibers. This is important because slow-twitch fibers are more efficient at using oxygen, helping muscles sustain activity longer without fatigue, unlike fast-twitch fibers, which tire more quickly.
• Improves muscle metabolism and efficiency — The researchers also found that melatonin-treated rats had a higher proportion of oxidative muscle fibers, which require less energy to sustain contractions and allow muscles to function more efficiently. This fiber shift means muscles are better equipped for sustained movement and improved endurance capacity, which is important for individuals with metabolic disorders.
• Boosts cellular energy production — The study showed that melatonin improved mitochondria by increasing their ability to convert nutrients into ATP (energy). This means cells produced more ATP while generating less waste. This made muscle cells more energy-efficient and better equipped to handle metabolic stress.
• Protects muscle cells from oxidative stress — In diabetes, mitochondria produce excess reactive oxygen species (ROS), which damage muscle tissue and accelerate aging. Melatonin lowered ROS levels while boosting antioxidant enzyme activity, especially superoxide dismutase (SOD), which neutralizes harmful molecules. This helps protect mitochondrial integrity and prevent muscle breakdown.
• Strengthens muscle cells at a deeper level — Researchers found that melatonin activated key proteins involved in cellular defense and muscle adaptation, helping muscles resist metabolic stress and recover more effectively.
• Enhances fat-burning in muscles — Melatonin improved how muscle cells processed fat by increasing the activity of enzymes that convert fat into energy. This meant muscles used fat more efficiently instead of storing it, which is especially important for people with obesity and diabetes, as poor fat metabolism leads to weight gain and worsens health problems.
• Works even better in females — Female diabetic rats showed greater improvements in oxidative muscle fibers and energy production, suggesting melatonin’s benefits may be influenced by hormones. This could be especially helpful for postmenopausal women at risk of muscle loss and metabolic decline.
• Maintains strength and energy despite diabetes — By improving energy production, fat metabolism, and muscle protection, melatonin helps counteract muscle loss in diabetes and obesity. It supports endurance, strengthens muscle fibers, and reduces cellular stress, making it a powerful tool for muscle health.
This study builds upon years of research from the University of Granada, which has progressively examined how melatonin supports mitochondrial function, muscle composition, and metabolic health.
How Does Melatonin Enhance Fat Burning and Metabolic Health?
A 2021 study conducted by the research team from the University of Granada, published in Antioxidants (Basel),3 was one of the first to investigate melatonin’s role in metabolic regulation. This study focused on brown adipose tissue (BAT). Unlike white fat, which stores energy, BAT burns fat to produce heat, which helps keep the body warm and regulates metabolism.
However, in people with obesity and diabetes, BAT function declines, leading to slower metabolism, increased fat storage, and impaired energy balance. Researchers aimed to see if melatonin could restore BAT’s ability to burn fat efficiently, improve mitochondrial function, and reduce stress inside cells. According to their findings, melatonin:
• Improves how brown fat burns energy — The study found that melatonin increased the efficiency of mitochondria inside BAT, allowing them to generate energy more effectively. This meant cells produced more ATP (the body’s main energy currency) while wasting less energy.
• Boosts calorie-burning capacity — Melatonin increased levels of UCP1, a protein that turns on BAT’s calorie-burning function. With higher UCP1 activity, BAT cells burned more fat for fuel, helping to improve overall metabolism. Additionally, melatonin increased the number and activity of mitochondria in BAT, further enhancing its ability to burn calories and regulate body temperature.
• Protects brown fat from cellular damage — In metabolic diseases like diabetes, cells produce high levels of harmful ROS, which damage mitochondria and make fat-burning less efficient. The study found that melatonin reduced oxidative stress by boosting antioxidant enzyme activity, which helped neutralize harmful molecules and preserve BAT’s fat-burning function.
• Improves metabolic flexibility — Healthy metabolism depends on your body’s ability to switch between burning fat and glucose for energy, depending on demand. In diabetes, this flexibility is often lost, making it harder to burn stored fat. Melatonin helped restore this ability in BAT, making it easier for the body to balance energy use and prevent insulin resistance.
How Melatonin Increases Mitochondrial Health and Muscle Composition
Building on these results, a 2023 study also published in Antioxidants (Basel)4 by the same research group shifted the focus from BAT to skeletal muscle, your body’s primary site for movement, strength, and glucose use. They investigated whether melatonin could restore muscle energy production, improve endurance, and protect against muscle deterioration, and found that it:
• Helps muscle cells produce energy more efficiently — Melatonin helped mitochondria maintain their normal function by regulating fission (splitting) and fusion (merging), two processes that keep mitochondria healthy. This prevented energy breakdown and kept muscle cells working more efficiently.
• Activates key muscle-protective enzymes — Melatonin activated SIRT1, an enzyme that shields muscle cells from oxidative stress and improves endurance-based muscle fibers. This means muscle tissue was better protected from the harmful effects of diabetes, reducing fatigue, and preserving strength.
• Promotes cellular renewal — In diabetes, damaged mitochondria accumulate inside muscle cells, making them weaker and more prone to breakdown. The study found that melatonin stimulated autophagy, a process where muscle cells remove damaged mitochondria and replace them with new, fully functional ones. This kept muscle cells stronger, healthier, and more resilient over time.
• Increases fatigue-resistant muscle fibers — Skeletal muscle contains different types of fibers, some designed for quick bursts of energy (fast-twitch fibers) and others for endurance (slow-twitch fibers). The study found that melatonin increased the proportion of oxidative muscle fibers (Type I and Type IIa), which are better at using fat for fuel and resisting fatigue. This means muscles could sustain activity for longer without becoming exhausted.
These findings reinforced the idea that melatonin plays an essential role in supporting skeletal muscle metabolism, improving endurance capacity, and protecting against muscle degeneration in metabolic disorders.
Melatonin Optimizes Energy Expenditure and Prevents Fat Storage
A 2024 study published in Biomedicine and Pharmacotherapy5 expanded upon these findings, combining insights from both skeletal muscle and brown fat studies to investigate melatonin’s broader metabolic effects. Researchers explored how melatonin activates key metabolic pathways that regulate energy balance, endurance and mitochondrial biogenesis (the process of creating new mitochondria). Their findings showed that melatonin:
• Stimulates muscle cells to burn extra energy instead of storing it as fat — Melatonin increased levels of sarcolipin (SLN), a protein that prevents muscles from storing excess energy. Instead, SLN forces muscle cells to burn extra energy as heat rather than storing it as fat, helping to reduce fat buildup while increasing energy expenditure.
• Activates key energy-regulating pathways — Researchers discovered that melatonin turned on a metabolic system that helps muscles generate energy, burn fat, and build stronger mitochondria. This activation enhances the body’s ability to generate sustained energy and resist metabolic stress.
• Improves muscle metabolic efficiency — Skeletal muscle in melatonin-treated rats showed higher mitochondrial function, making muscles more resistant to fatigue and better equipped to handle metabolic stress.
• Prevents fat buildup even without diet or exercise changes — One of the most striking findings was that melatonin led to significantly lower visceral fat storage, even without changes in food intake or physical activity. This suggests that melatonin increases energy expenditure, making the body burn more calories at rest while improving the ability to switch between burning fat and glucose.
This study provided even more evidence that melatonin is a key regulator of metabolism, not just a sleep hormone. To learn more about the role melatonin plays in your health, read “What You Need to Know About Melatonin.”
How Sunlight Triggers Mitochondrial Melatonin Production
While melatonin is commonly associated with the pineal gland and nighttime sleep cycles, over 95% of your body’s melatonin is actually produced inside your mitochondria, and this process depends on your exposure to natural sunlight.6
• Near-infrared (NIR) light from the sun drives this process — NIR light, which is abundant in early morning and late afternoon sunlight, ranges from 800 to 1,000 nanometers. This range of wavelengths is invisible and has the ability to penetrate deep into your skin and activate cytochrome c oxidase in your mitochondria. This key enzyme stimulates the production of mitochondrial melatonin.7
• Mitochondrial melatonin acts as a powerful antioxidant — Unlike pineal melatonin, which follows the circadian rhythm, mitochondrial melatonin production neutralizes free radicals before they damage cellular structures, similar to how plants boost melatonin levels when exposed to environmental stressors like heat or drought.8,9
• Natural sunlight is non-negotiable — Anytime your bare skin is exposed to natural sunlight, you can be sure you’re receiving the NIR wavelengths needed to trigger melatonin production in your mitochondria. Conversely, when indoors under artificial lighting, you can be certain you’re not getting any.
• Artificial light fails to trigger this process — Artificial lighting, no matter how advanced, cannot replicate the full spectrum of natural sunlight. Most indoor lighting lacks the NIR wavelengths. Even sitting near a window offers no benefit, since low-emissivity (low-e) glass filters out the majority of NIR radiation.
To learn more about the benefits of NIR light, check out “Light Therapy Might Help Ease ‘Dry’ Form of Macular Degeneration.”
How to Optimize Your Melatonin Production Naturally
While melatonin supplementation is beneficial for certain health conditions, it’s also important to support your body’s natural melatonin production. Although melatonin has a strong safety record, long-term high doses (over 5 to 10 milligrams) may pose risks.
One concern is that melatonin helps release heavy metals like mercury from the body, which may cause damage unless properly detoxified. If taking higher doses, it’s best to follow a good detox plan and use a sauna regularly to flush out toxins. To naturally optimize your melatonin production, follow these tips:
• Get bright sunlight during the day — As explained above, sunlight plays an important role beyond regulating your circadian rhythm, which lowers melatonin during the day and increases it at night. It also delivers the wavelengths needed to activate mitochondrial melatonin production. Try to spend at least 15 minutes in the morning sun to support both sleep and cellular health.
However, it’s important to avoid high-intensity sun exposure until you’ve been off vegetable oils for about six months, as these oils significantly raise your risk of sunburn. Discover the keys to safer sun exposure in “The Role of Sun Exposure in Optimizing Your Cellular Health.”
• Limit blue light exposure at night — Blue light from phones, computers and LED lights suppresses melatonin production, making it harder to fall asleep. In the evening, use dim lighting, salt lamps, or incandescent bulbs instead of harsh LEDs. If you must use screens, wear blue-blocking glasses or install blue-light filtering software.
• Sleep in total darkness — Even small amounts of light can disrupt melatonin levels. Use blackout curtains, a sleep mask, or remove glowing electronics to create a pitch-dark sleeping environment.
• Manage stress before bed — High stress raises cortisol, which blocks norepinephrine, the hormone needed for melatonin release. Try meditation, stretching or deep breathing before bed and avoid stressful activities like work or intense discussions in the evening.
By following these natural strategies, you will help your body produce enough melatonin for restful sleep and better overall health.
Frequently Asked Questions (FAQs) About Melatonin and Muscle Health
Q: How does melatonin help prevent muscle loss?
A: Melatonin protects muscles from deterioration caused by obesity and diabetes by improving energy production, reducing oxidative stress and supporting muscle fiber regeneration.
Q: Can melatonin boost energy and endurance?
A: Yes. Melatonin helps your mitochondria work better, meaning your cells create more energy with less waste. It also shifts muscle composition to favor endurance fibers, so you stay active longer without getting tired as quickly.
Q: Does melatonin help burn fat?
A: Yes, melatonin encourages your muscles to burn fat for fuel instead of storing it. It also activates key metabolic pathways that regulate energy and prevent excess fat accumulation, making it a great tool for managing weight.
Q: What’s the best way to boost melatonin naturally?
A: To support natural melatonin production, get bright sunlight during the day, limit blue light exposure at night, sleep in total darkness and manage stress levels. These steps help regulate your circadian rhythm and optimize melatonin release.
Q: Is it safe to take high doses of melatonin?
A: Melatonin is generally safe, but very high doses (over 5 to 10 milligrams) may release stored toxins like mercury. If you’re taking higher doses, supporting detox with sauna sessions and proper nutrition helps minimize any risks.
