An Overview of the Potential Effects of Melatonin Supplementation on Athletic Performance

Melatonin is a hormone synthesized principally in the pineal gland that has been classically associated with endocrine actions. Exogenous melatonin is often used to treat insomnia and enhance sleep quality in a range of situations, including jet lag. However, the benefit and safety profile of daytime melatonin dosing prior to exercise are unknown and warrant additional exploration.

We aimed to give (i) a brief overview of the beneficial effects of exogenous melatonin administration on sports performance and (ii) some recommendations for acute use of melatonin with a special focus on humans’ physical activity and athletic performance.

To ascertain the effect of exogenous melatonin administration on humans, a systematic search of the literature was undertaken using PubMed, ScienceDirect, Medline, Google Scholar, and Scopus. Numerous studies in animals have demonstrated the positive impact of melatonin treatment during physical exercise. However, uncertainty remains regarding exogenous melatonin administration on human’s physical performance. Therefore, the present review focuses almost entirely on data obtained from humans.

The gathered data indicate that consuming melatonin at night improves sleep quality. In terms of physical activity and sports performance, previous research has demonstrated that melatonin administration has a good effect on decreasing oxidative stress and inflammation induced by exercise. Melatoninmay also provide additional protection for skeletalmuscle against exerciseinduced oxidative damage in humans. However, in some specific situations, the daily administration of melatonin may have an unfavourable influence on performance during acute and strenuous exercise.

Exogenous melatonin administration prior to exercise shows significant chronobiotic, antioxidant, antiadrenergic, and hypothermic effects and may represent a fascinating potential weight loss method. However, consuming a high amount of melatonin (6mg) 50minutes prior to commencing exercise is not recommended as itmay interfere with the physiological reactions to physical activity. Melatonin-related adverse effects were mainly transient and were associated with daytime doses. Melatonin should therefore be consumed at night whenever possible.