Melatonin Dosage Calculator

Melatonin is a hormone your body naturally produces to regulate sleep-wake cycles.
Supplemental melatonin can help with sleep onset, jet lag, and shift work adjustment.

General dosage guidelines:

Important principles:

• Start low: Begin with the smallest effective dose. More is not better with melatonin.
• Timing matters: Take 30–60 minutes before your desired bedtime.
• Short-term use: Melatonin is generally recommended for short-term use (2–8 weeks).
• Jet lag: Use 0.5–5 mg at bedtime for the first few nights at your destination.

Factors that affect dosage:

• Not body weight, which is why this calculator does not ask for it. Melatonin acts as a timing signal, and the trials behind these doses gave everyone the same amount whatever they weighed.
• Age (older adults produce less natural melatonin but are also more sensitive to it).
• Light exposure (screen time before bed suppresses natural melatonin).
• Caffeine intake (can reduce melatonin effectiveness).

Side effects at high doses: Headache, dizziness, nausea, and daytime drowsiness.

Why the max column matters more than the starting dose

The maximum in that table is not a target to work up to. It is a ceiling, and the ceiling for a child is 3 mg, not the 10 mg an adult may take. Paediatric melatonin overdose calls to US poison centres rose more than 500% between 2012 and 2021, driven largely by gummies left within reach, so the gap between a child’s dose and an adult’s is the single most important number on this page.

More is not better, and the research is unusually clear about it

Melatonin is a timing signal rather than a sedative. It tells your body clock that night has started; it does not knock you out the way a sleeping pill does. The Cochrane review of the jet lag trials (Herxheimer and Petrie, 2002) found 0.5 mg and 5 mg about equally effective, with 5 mg getting people to sleep a little faster, and nothing gained above 5 mg. If 1 mg does nothing for you, 10 mg is unlikely to be the answer, and the problem is usually timing or light exposure instead.

For long-standing insomnia in adults the evidence is thinner still. The American Academy of Sleep Medicine’s 2017 guideline suggests not using melatonin for it at all, because the benefit in trials was too small to matter. Cognitive behavioural therapy for insomnia (CBT-I) is the first-line treatment.

Supplements in the US are not held to pharmaceutical standards. When researchers tested 25 melatonin gummy brands sold in the US (Cohen and colleagues, JAMA, 2023), 22 were inaccurately labelled, and the melatonin actually present ran from 74% to 347% of the label. One held no melatonin at all, only CBD. An earlier study of 31 products bought in Canada (2017) found the same pattern, from 83% below the label to 478% above it. Buy a brand carrying a USP or NSF verification mark if you can.

Always consult your doctor before giving melatonin to children or if you take other medications.
Melatonin is not recommended during pregnancy or nursing without medical advice.