Melatonin Supplements: Dosage, Timing, and What to Know

How Melatonin Works

Melatonin is a hormone produced by the pineal gland in your brain. Its primary role is signaling to your body that it is time to sleep. It does not knock you out the way a sedative does. Instead, it shifts your circadian rhythm and promotes sleep readiness.

• • Natural production: Your brain starts releasing melatonin about 2 hours before your usual bedtime in response to dimming light. Levels stay elevated through the night and drop off in the early morning as light increases.
• • Circadian signal, not a sedative: Melatonin tells your body clock that nighttime has arrived. It lowers core body temperature and promotes drowsiness, but it does not force sleep the way prescription sleep medications do.
• • Light suppresses production: Bright light, especially blue light from screens, suppresses melatonin release. This is one reason screen use before bed can delay sleep onset.

Because melatonin is a timing signal rather than a sedative, taking it at the right time matters more than taking a large dose.

Why Less Is Often More

Most melatonin supplements on store shelves come in 5mg, 10mg, or even 20mg doses. These are much higher than what research supports for most people. Your body naturally produces about 0.1-0.3mg of melatonin per night.

• • Effective range: Most clinical studies find that 0.5-3mg is effective for sleep onset. A 2005 meta-analysis in Sleep Medicine Reviews found doses in the 0.3-5mg range all reduced sleep latency (time to fall asleep), with no clear dose-response relationship above 0.5mg.
• • Higher is not better: Doses above 5mg can overshoot your body's melatonin receptors, potentially causing desensitization. Some people report that high doses make them wake up in the middle of the night or feel groggy the next morning.
• • Start low: Sleep researchers at MIT, where melatonin's sleep effects were first characterized, have recommended 0.3-1mg as a starting dose. If that does not work, increasing to 3mg is reasonable before going higher.

If you have been taking 10mg and it stopped working, try dropping to 1-2mg for a week. Some people find lower doses work better after a reset period.

Forms of Melatonin Supplements

Melatonin comes in several delivery formats. The differences matter mostly in terms of how quickly the melatonin is absorbed and how long it stays active.

What the Research Says

Melatonin is one of the better-studied sleep supplements. The evidence is strongest for specific situations rather than general insomnia.

• • Jet lag: This is melatonin's best-supported use case. A Cochrane review of 10 trials found melatonin significantly reduced jet lag severity when taken close to bedtime at the destination, particularly for eastward travel crossing 5 or more time zones. Doses of 0.5-5mg were similarly effective.
• • Delayed sleep-wake phase disorder: People whose internal clock is shifted later than desired (common in teenagers and young adults) benefit from low-dose melatonin (0.5-1mg) taken 3-5 hours before the desired bedtime. This use is well-supported by circadian rhythm research.
• • Sleep onset latency: A 2013 meta-analysis of 19 randomized controlled trials in PLoS ONE found melatonin reduced sleep onset latency by an average of 7 minutes and increased total sleep time by about 8 minutes. These effects are statistically significant but modest compared to what many people expect.
• • Shift work: Evidence is mixed. Some studies show melatonin helps night shift workers sleep during the day, but results depend heavily on timing, light exposure, and individual variation. It is not a reliable fix for chronic shift work sleep problems on its own.
• • Older adults: Melatonin production declines with age. A 2017 review found that melatonin improved sleep quality in adults over 55, with extended-release formulations showing the most consistent benefits in this group.

Melatonin works best for circadian-related sleep issues. If your insomnia is caused by anxiety, pain, sleep apnea, or other medical conditions, melatonin alone is unlikely to solve the problem.

Who Benefits Most From Melatonin

Melatonin is not a one-size-fits-all sleep aid. It works best for specific groups and situations:

• • Frequent travelers: If you regularly cross time zones, melatonin is one of the most effective tools for resetting your sleep schedule quickly.
• • Night owls trying to shift earlier: People with a naturally late chronotype who need to wake up early for work or school can use low-dose melatonin in the early evening to advance their internal clock.
• • Adults over 55: Age-related decline in melatonin production means older adults are more likely to notice a benefit from supplementation, especially extended-release formulations.
• • People with occasional sleep difficulty: If you generally sleep well but occasionally struggle to fall asleep due to stress, schedule changes, or seasonal light shifts, short-term melatonin use can help reset your pattern.

If you have chronic insomnia lasting more than 3 months, talk to a doctor before relying on melatonin. Cognitive behavioral therapy for insomnia (CBT-I) is considered the first-line treatment and has better long-term outcomes than any supplement.

What to Look For in a Melatonin Supplement

Timing, Safety, and Side Effects

Getting the timing right matters as much as the dose. Melatonin is generally safe for short-term use, but there are situations where caution is warranted:

• • Timing: For sleep onset, take melatonin 30-60 minutes before bed. For circadian shifting (delayed sleep phase), take it 3-5 hours before your desired bedtime. Taking it too late or too close to wake time can cause morning grogginess.
• • Next-day drowsiness: The most common complaint, especially at doses above 3mg. If you feel groggy in the morning, lower your dose or take it earlier in the evening.
• • Drug interactions: Melatonin can interact with blood thinners (warfarin), blood pressure medications, diabetes medications, immunosuppressants, and seizure medications. It may also increase the sedative effects of benzodiazepines, zolpidem, and alcohol. Check with your doctor if you take any prescription medications.
• • Autoimmune conditions: Melatonin may stimulate immune function. People with autoimmune conditions should consult their doctor before using it, as it could theoretically worsen symptoms.
• • Pregnancy and breastfeeding: There is not enough safety data to recommend melatonin during pregnancy or breastfeeding. Most experts advise against it in these situations.