Chronic Administration of Melatonin: Physiological and Clinical Considerations.

Melatonin at low to moderate dosages (approximately 5-6 mg daily or less) appears safe. Long-term usage appears to benefit certain patient populations, such as those with autism spectrum disorder. Studies investigating potential benefits in reducing cognitive decline and increased longevity are ongoing. However, it is widely agreed that the long-term effects of taking exogenous melatonin have been insufficiently studied and warrant additional investigation.