Melatonin looks like a recovery aid for athletes, not a performance booster

Melatonin is best known as the hormone that governs sleep, but it also has antioxidant, anti-inflammatory and immune-regulating properties. Highly trained athletes put their bodies under repeated physical stress, and that stress shows up in blood markers of inflammation and muscle damage. That raises an obvious question: could supplementing melatonin protect athletes' health, and might better health feed through into better performance? Until now, the trial evidence on this specific group had not been pulled together systematically.

The authors swept three major research databases, Web of Science, PubMed and Scopus, for controlled trials of melatonin supplementation in highly trained athletes, with the search updated in February 2024. They screened 294 references and selected 21 articles that met their inclusion criteria. Study quality was checked with established tools, including the PEDro scale and the Cochrane risk of bias assessment. Across the included trials, melatonin doses ranged from 5 mg to 100 mg, taken either before or after exercise.

The clearest signals were improvements in antioxidant status and the inflammatory response, along with reversal of markers of liver damage and muscle damage. Effects on blood sugar, total cholesterol, triglycerides and creatinine were described as moderate. Data on blood cell markers, hormonal responses and sports performance itself were promising rather than conclusive. Crucially, the authors state that melatonin's true ability to directly improve sports performance remains to be assessed.

This review extends melatonin's reputation well beyond sleep, positioning it as a possible recovery and health support for athletes under heavy training loads. It fits a broader pattern of interest in antioxidant and anti-inflammatory supplements in sport. The wide dose range across trials, from 5 mg to 100 mg, leaves the practical question of how much and when completely open. The biggest gap is direct performance testing, because better biomarkers do not automatically mean faster races or bigger lifts.

If you train hard and have only heard melatonin discussed as a sleep aid, this is a reason to see it differently: in athletes it has been linked to better recovery-related blood markers. It is not, on this evidence, a performance enhancer, and anyone expecting a direct boost to speed or strength is ahead of the science. The findings come from highly trained athletes, so they may not transfer to casual exercisers. As ever with supplements, this is information rather than a recommendation.