Melatonin Dosage Calculator
Compared to what's commonly sold in stores:
At 65+, metabolism slows, so blood levels from the same dose can stay elevated longer. Start at the low end (0.3mg) rather than the high end.
Based on Brzezinski et al. (2005), a meta-analysis of 17 studies (284 subjects) in Sleep Medicine Reviews, which found the sleep-onset effect plateaus around 0.3mg — higher doses added side effects, not benefit. This calculator deliberately isn't weight-based; no study supports scaling melatonin dose to body weight. This is general health information, not medical advice — talk to your doctor about chronic insomnia or if you're pregnant, nursing, or on other medication.
Free melatonin dosage calculator based on the actual dose-response research (Brzezinski et al. 2005, Sleep Medicine Reviews) — see the effective starting dose range, why it's far lower than most store-bought pills, and how it compares to what's commonly sold.
How it works
- Pick your purpose: trouble falling asleep, or jet lag
- Pick your age group: adult, or 65+
- See the research-backed starting dose range (0.3-1mg) next to common commercial doses (3mg, 5mg, 10mg) so you can see the gap
Frequently asked questions
Why isn't this calculator based on my body weight?
Unlike drugs dosed per kilogram, melatonin is a signaling hormone whose sleep effect plateaus at a very low, roughly fixed dose — not one that scales with body size. A 2005 meta-analysis (Brzezinski et al., Sleep Medicine Reviews, 17 studies, 284 subjects) found the effect plateaus around 0.3mg, with higher doses adding side effects but not benefit. Some calculators use a weight-based formula (like weight × 0.03), but we couldn't find a study supporting that approach, so we don't use one either.
Why do most melatonin pills sold in stores contain 3-10mg?
Manufacturers generally aren't required to dose supplements at the research-backed minimum — and in the US, melatonin is regulated as a dietary supplement, not a drug, so doses aren't standardized around clinical trial findings the way a prescription would be. Harvard Health notes that going above 2-3mg likely doesn't work any better than 1mg or less, and that the share of people taking more than 5mg has risen sharply in recent years.
Is a higher dose more likely to help me sleep better?
The research says no for typical sleep-onset or jet-lag use — doses above roughly 3mg haven't been shown to add benefit, only added next-day grogginess risk. Higher doses may be appropriate for specific medical situations, but that's a conversation for your doctor, not something to self-titrate toward.
Can I trust the milligram amount on the label?
Not always. Because melatonin supplements aren't FDA-approved drugs, quality varies by brand — studies (particularly of gummy products) have found actual content ranging from 74% to 347% of the labeled amount. Choosing a third-party tested brand reduces this risk.
Related tools
From the blog
Update history
- 2026-09-23 Launched: melatonin dosage calculator based on Brzezinski et al. 2005 (Sleep Medicine Reviews, 17-study meta-analysis) showing the effective dose plateaus around 0.3-1mg, compared against common commercial doses of 3-10mg. Deliberately not weight-based — no evidence supports a weight-proportional formula for melatonin.