https://www.verywellfit.com/how-melatonin-helps-with-fat-loss-and-muscle-gain-4141253 Xavier Galindo Torres / EyeEm/Getty Images Melatonin is a naturally occurring hormone in the body and a well-known supplement used to improve sleep patterns. Inadequate sleep can interfere with optimal body function and overall fitness. According to research, melatonin improves our sleep but has other positive effects on the body. It appears melatonin may increase metabolism, weight loss, and provide protection for muscle tissue.1 How can a common sleep aid help with body fat reduction and enhance muscle? Before answering that question, we need to understand how melatonin functions in the body. The Role of Melatonin Melatonin, also known as the darkness hormone, is secreted by the pineal gland in the brain and is responsible for regulating our circadian rhythm.2 Circadian rhythm is an internal clock our body runs on over a 24-hour period. It’s basically the motor controlling our wake and sleep cycles. Our circadian rhythm works best when we have regular sleep habits. It’s also sensitive to external cues like sunrise and sunset. When it gets dark and close to bedtime, the brain stimulates the release of melatonin, which makes us feel tired. Melatonin reaches peak levels in the middle of the night while we’re sleeping. As the sun rises, melatonin levels drop, signaling the body to wake. Since melatonin is the main hormone regulating our circadian rhythm, addressing any sleep problems along with melatonin is essential. Without quality sleep, our body composition, energy levels, nutrition and ability to exercise can be adversely affected. How Does Melatonin Help Reduce Body Fat? According to research, melatonin may increase metabolism and improve our ability to lose weight. In order to prove this theory, a study was conducted examining how melatonin affected body composition, lipids, and glucose metabolism in postmenopausal women.3 Menopause just so happens to be a time in a woman’s life where losing fat and gaining muscle can be a struggle. The small randomized study included 81 postmenopausal women who supplemented with melatonin (1 or 3mg nightly) or a placebo for one year. Body composition was measured using a DXA scan prior to and after the trial period. Blood was drawn to record baseline and ending values of how melatonin affected leptin, adiponectin and insulin levels. These are hormones that help regulate metabolic processes including how our body burns fat and glucose (sugar). The women who supplemented with melatonin decreased fat mass by 7 percent compared to the placebo group. They were also able to increase lean mass by 2.6 percent compared to the placebo participants. Adiponectin hormone increased significantly by 21 percent in the melatonin group. Adiponectin is a protein hormone involved in how the body regulates glucose levels and the breakdown of fatty acids. Research results indicate melatonin has a beneficial effect on body composition and fat oxidation (burning). Supplementing with melatonin for 12 months was shown to reduce body fat, increase lean mass, and increase levels of adiponectin, which improves how the body burns fat. Can It Increase and Protect Lean Mass? Melatonin is shown to increase the lean mass of postmenopausal women. Other research indicates it also protects athletes from muscle damage. In order to build muscle, a balanced and protective internal environment is essential. It appears melatonin can reduce exercise-induced oxidative stress and provide a better environment for muscle protection and growth. Melatonin contains antioxidant properties that appear to reduce exercise-induced oxidative stress. Oxidative stress occurs when there is an imbalance or compromise of normal body functions in response to intense exercise. This can lead to muscle fatigue and damage along with decreased energy. A study was conducted to examine the effects melatonin would have on chemical reactions and muscle damage in resistance-trained athletes.4 During this short randomized study, 24 athletes supplemented with either melatonin (100mg/day) or placebo. This amount is significantly higher compared to what our body produces naturally per day. The participants were required to increase exercise intensity during the trial period. High-intensity exercise can cause the release in the body of chemicals that are potentially harmful to our muscles and cells. The research included blood tests checking for these chemicals plus other enzymes and antioxidants beneficial to muscle growth. Research results indicated the following: Athletes supplementing with melatonin showed an increase in total antioxidant capacity for muscle protection compared to the placebo group. Participants taking melatonin were able to reduce harmful chemical levels indicating less exercise-induced muscle damage from oxidative stress than the placebo group. Melatonin prevented the increase of chemical toxins created during oxidative stress compared to the placebo group. The melatonin group maintained a higher ratio of protective enzymes to help preserve muscle tissue compared to those using a placebo. Total cholesterol levels were also reduced in the melatonin group compared to placebo. Researchers concluded melatonin was beneficial to resistance-trained athletes. Melatonin helps prevent exercise-induced oxidative stress and offers muscle tissue protection against oxidative damage. Adequate Levels of Melatonin and Physical Training An interesting animal study examined how daily melatonin supplementation improved energy adaption to exercise as we age.5 Rodents were used in the research over a 16-week period. Researchers indicated melatonin plays an important role in the metabolic adaptions of fat and muscle tissue to physical training. Decreased amounts of melatonin occur as we age, causing a decline in the efficiency of our body responses to exercise. In fact, animals unable to produce melatonin failed to develop metabolic changes in response to aerobic exercise according to research. The study separated the rats into four groups (sedentary and trained rodents—no melatonin and sedentary and trained rodents—melatonin-supplemented). The rats were placed on an exercise program during the final 8 weeks of the research period. Research indicated the trained rats supplementing with melatonin presented better results compared to the three other groups. The following areas were reported as improved with melatonin: Physical capacity Glucose tolerance Muscle glycogen content Body weight Enzyme function Fat metabolism Glucose metabolism Insulin sensitivity The positive findings indicate melatonin supplementation could be beneficial to maintain body function as we age. Adequate levels of melatonin are shown to play an important role in the metabolic adaptations induced by aerobic exercise. It appears melatonin may be helpful in improving our metabolism, reducing body weight and increasing insulin sensitivity. Although the results are promising, the metabolism of rats is far different from the metabolism of humans, and the results of rat studies (which are commonly employed only because rats are cheap and not cute) can only be used to generate hypotheses, that then need to be tested on humans. Heart health (angina, hypertension, reduced risk of heart attack) Anti-aging Improved gastrointestinal health Decreased migraine headaches Numerous studies have shown naturally occurring and supplemented melatonin to protect the body from disease caused by free radical damage. However, using high dose melatonin for prolonged periods of time, while an interesting proposition that may eventually turn out to be advisable, is not something one ought to do today without a doctor’s approval, despite the fact that this stuff is readily available at any dose. Further research to discover other functions and more conclusive evidence on melatonin supplementation is recommended. Should You Take Melatonin? There is enough evidence to show melatonin as beneficial to improving our health and fitness. However, this may not necessarily mean supplementing with melatonin is the best fit for you. Your body may already be producing adequate levels of melatonin to support optimal fitness. There are a few things to consider before moving forward with the choice to use melatonin. According to the National Institutes of Health, melatonin may help some people with sleep problems related to insomnia, jet lag or shift work.7 Although the physiologic dose (.1 to .5 mg) of melatonin is shown effective for certain kinds of insomnia and in treating jet lag, larger doses remain questionable. Higher doses can actually raise our melatonin levels even during the day and alter our normal day/night circadian rhythm. It’s unclear whether enough evidence exists to support melatonin as a treatment for other conditions. Although research has discovered positive clinical findings, it appears further research is recommended. Melatonin is indicated to be a safe supplement when taken short-term. More studies are required to investigate the safety and effectiveness of long-term use. Take an honest look at research outcomes and talk to your doctor before you supplement with melatonin. Melatonin is included as one of the dietary supplements regulated by the Food and Drug Administration (FDA), but the regulations are less strict compared to prescription drugs. Supplements are typically unregulated so having at least some regulation on melatonin is a good thing. According to research, there is no recommended dose for melatonin supplements. Most studies begin with a conservative dose (< 0.3 mg per day) which is close to what our body produces naturally. Starting with the lowest amount to achieve desired results appears to be the best option. However, it’s important to discuss taking melatonin with your physician. They will be able to help you decide the best dose for your situation and recommend any increases if needed. Possible side effects of melatonin supplementation may include: Vivid dreams or nightmares Disruption of circadian rhythms if too much is taken Drowsiness if taken during the day Drowsiness upon waking if too much is taken the night before Additional side effects may include stomach cramps, dizziness, headache, irritability, reduced libido, and reduced sperm count in men. Precautionary information includes: Some studies have indicated melatonin may worsen the symptoms of depression. Pregnant or nursing women should not take melatonin because it could interfere with fertility or pregnancy. Melatonin may interact with certain prescribed medications. If you are taking prescribed medications, talking with your doctor is advised before taking melatonin. High doses of melatonin have also been associated with daytime sleepiness, hyperprolactinemia, hypothermia, and impaired physical performance. A Word From Verywell Melatonin is shown to improve our ability to lose fat, gain muscle, and is a potential treatment for improved general health. The positive findings are impressive and further research is predicted to uncover more health benefits of melatonin. Although it appears to be a safe short-term treatment option, there is a concern for long-term use given lack of research in this area. If you are considering taking melatonin for improved fitness or sleep problems, talking to your doctor first would be a good idea.