Melatonin
Hormone Restoration
In plain English
Melatonin is a hormone the body releases at night to signal that it is time to sleep. Taken as a supplement it can modestly help people fall asleep and is used for jet lag and shift work. It is usually taken as a capsule before bedtime, often in a slow-release form. Effects on sleep are real but generally modest.
The science
Melatonin is a pineal hormone that acts on MT1/MT2 receptors to regulate circadian rhythm and promote sleep onset. A meta-analysis of 19 randomized placebo-controlled trials (Ferracioli-Oda 2013) found melatonin significantly reduced sleep-onset latency (~7 minutes) and increased total sleep time (~8 minutes) and sleep quality—modest effects that do not diminish with continued use and with a benign side-effect profile relative to hypnotics. It is chronobiotic (useful for phase shifting in jet lag/shift work) as well as mildly hypnotic. In the U.S. melatonin is sold as a dietary supplement (not FDA-approved as a drug), so purity/potency vary by product; sustained-release forms aim to mimic overnight physiology. Common effects are next-day grogginess, vivid dreams, and headache.