The claimEvidence A · guideline-tier
5-10 mg melatonin helps you sleep
The evidence
0.3 mg is the physiological equivalent; 5-10 mg overloads receptors → next-day grogginess + rhythm disruption.
Why the claim spreads
Sold over-the-counter in big doses in the US, feeding the 'more = stronger' intuition; most people never learn the effective dose is far smaller.
The mechanism, in brief
Melatonin is the body's own 'nighttime signal' hormone, secreted mainly by the pineal gland deep in the brain.
Sources (1)
- Brzezinski, A., et al. (2005). Effects of exogenous melatonin on sleep: a meta-analysis. Sleep Medicine Reviews, 9(1), 41–50.