Is Low-dose melatonin (0.3–0.5 mg) worth it?
Useful for timing problems — jet lag, delayed sleep phase, shift rotation — at a tiny dose. It's a circadian signal, not a sedative, and not a first choice for ordinary chronic insomnia. Timing matters more than dose.
The call
Melatonin signals "biological night," so it helps circadian misalignment most. Meta-analysis shows modest shortening of time-to-fall-asleep and a small total-sleep increase, with heterogeneity. For chronic insomnia, the major sleep-medicine guideline gives a weak recommendation against it (low-quality evidence). Physiologic low doses are enough for the circadian signal; higher doses tend to add morning grogginess without clearly improving sleep.
Safety
Grogginess and vivid dreams; don't drive after dosing. Interaction cautions: anticoagulants/antiplatelets, sedatives, seizure disorders, immunosuppressants, diabetes/BP meds, and CYP1A2 inhibitors (e.g. fluvoxamine). Pregnancy and children: clinician-guided, especially long term.
Dose that matters: 0.3–0.5 mg, timed (a few hours before target sleep for phase-shifting)
Sources
Tier 2 · evidence synthesis · Reviewed by the Stack-kit desk