Melatonin is a hormone primarily known for regulating the sleep-wake cycle, or circadian rhythm, in vertebrates. In humans, it is produced by the pineal gland in the brain in response to darkness, typically starting a few hours before bedtime. Light exposure decreases melatonin production, signaling the body to wake up. Melatonin supplements are often used to help with insomnia, jet lag, and other sleep-related issues. They can reduce the time it takes to fall asleep, especially for those with delayed sleep phase syndrome or non-24-hour sleep-wake disorder.
Beyond sleep, melatonin has antioxidant and anti-inflammatory properties and may help with eye health, seasonal depression, and GERD. It can neutralize free radicals and promote the expression of antioxidant enzymes. However, recent research suggests caution with long-term use. A study presented at the American Heart Association's Scientific Sessions 2025 found that long-term melatonin use for insomnia was associated with a higher risk of heart failure, hospitalization for heart failure, and mortality. While generally considered safe, melatonin can interact with certain medications and is not recommended for children. Experts recommend consulting with a healthcare professional before starting melatonin, especially for long-term use.
