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Sports Nutrition

Melatonin for Muscle

Most people know melatonin for one thing: promoting sleep. But it has another, more provocative benefit: growing muscle.


Insomniac? Take melatonin. Flying to the other side of the world and want to be bright-eyed when you get there? Take melatonin. Heading into a workout and want to maximize muscle gains? Take…melatonin?

Melatonin is a naturally occurring hormone that has traditionally been recommended as a sleep aid or to assist with getting acclimated to a new time zone because it’s released by the brain following the body’s circadian rhythms (aka internal clock) and helps to regulate sleep and wake cycles. However, research also suggests that taking the hormone before workouts aids in muscle building, fat loss and recovery with very little effect on wakefulness or energy levels. That’s the part we focus on here.

Antioxidant Power

Intense exercise is associated with increases in oxidative stress. Research over the past several years has illustrated that antioxidants taken before exercise can increase workout performance and improve recovery. In the past two decades, scientists have shown that melatonin acts as one of the body’s most active antioxidants and free-radical scavengers — in fact, it’s about twice as active as vitamin E and synergizes with other antioxidants to improve their overall activity. A recent study conducted at the University of Seville Medical School in Spain looked at the effects on oxidative stress, immunity and fat metabolism of taking melatonin before intense exercise. Athletes took either 6 milligrams of melatonin or a placebo 30 minutes before completing an hour of continuous intense training. Upon completion of the study, the authors concluded that the melatonin supplement significantly increased blood-total antioxidant activity and decreased exercise-induced oxidative stress. Furthermore, they observed that the melatonin group had increased fat metabolism during training and improved immunity.

Beyond increases in oxidative stress, long and intense exercise bouts signal the body to release inflammatory factors that increase muscle soreness and cause significant muscle damage. As inflammation increases during training, many note a reduction in work performance, decreases in exercise intensity and the need for increased recovery time between sessions.

Related: Rest and Recovery: More is Better

A recent study published in the Journal of Pineal Research examined whether preworkout melatonin supplementation would improve the oxidative and inflammatory responses associated with intense training. In this study, a group of highly trained endurance athletes were given melatonin supplements or a placebo for three days before completing a grueling 50-kilometer uphill run in the Sierra Nevada mountains in Granada, Spain. The supplement regimen consisted of 3 milligrams of melatonin with dinner two days before the run, 9 milligrams (split between breakfast, lunch and dinner) the day before the run, and 3 milligrams one hour before the run. Blood and urine samples were taken before and immediately after the run and were tested for several markers of inflammation and oxidative stress. 

At the end of the study, the authors concluded that oral supplementation of melatonin during high-intensity exercise is efficient in reducing oxidative stress and markers of inflammation. In all, such improvements protect muscles from damage, thereby allowing training adaptations to happen more easily.

Anabolic Booster

After a bout of heavy exercise, the body mounts hormonal responses that increase anabolism, resulting in increased strength, exercise capacity and muscularity over time. One of the most critical hormones released during that recovery period is growth hormone, which, as its name implies, regulates muscular growth but also decreases fat mass. Under normal conditions, GH (like melatonin) follows the body’s internal clock, with the highest levels being released from the pituitary gland in the brain at the onset of deep sleep. Interestingly, studies have shown that taking up to 5 milligrams of melatonin before sleep or during wakeful hours results in increased blood growth-hormone levels — forming a link between blood melatonin levels and GH release.

Melatonin can influence the GH response to endurance and resistance exercise, too. A study conducted in the U.K. and published in the European Journal of Endocrinology in 1999 showed that taking 5 milligrams of melatonin one hour before a short bout of moderate-intensity cycling exercise results in a significant increase in GH release when compared to exercising after taking a placebo. Eight years later, scientists from Baylor University in Texas reported that trained males given 5 milligrams of melatonin one hour before a leg workout had higher GH levels before and after training compared to subjects who received a placebo. In fact, they illustrated that even test subjects who took just 0.5 milligrams of melatonin had higher GH levels after training. Together, these studies support the use of melatonin to boost GH secretion and maximize muscularity.

Taking Melatonin

Clearly, melatonin is a great supplement to take to improve oxidative status, augment GH release and promote restorative sleep at night, and the best way to reap these benefits is to take 0.5 to 5 milligrams 30 to 60 minutes before training and 0.5 to 5 milligrams immediately before hitting the sack. On rest days, take the preworkout dose at the same time as you would on training days.