hormone · for delayed sleep-wake phase
Melatonin
A small dose hours before bed nudges your body clock earlier. That is a different job from the sleepy effect of a big dose.
Say that in clinical terms
In delayed sleep-wake phase disorder the internal circadian clock runs later than the person's desired schedule; taking a small dose of melatonin several hours before the desired bedtime nudges (advances) that internal clock earlier, which is a different action from melatonin's separate, dose-dependent sedative effect.
How strong is the research?
1 paper read, 1 supporting.
Tested as: low-dose (0.5 mg fast-release) melatonin taken 1 hour before the patient's desired/target bedtime — NOT at the delayed bedtime the person has been naturally falling asleep at — on at least 5 nights per week, combined with behavioral sleep-wake scheduling (deliberately attempting sleep at the earlier desired time). The AASM guideline describes this generally as "strategically timed" melatonin, with timing set relative to the individual's circadian phase (e.g., dim-light melatonin onset) or desired bedtime rather than a fixed clock time — the timing, not a higher dose, is what does the work. The guideline notes that phase-shifting studies have not established any added benefit above 5 mg.
How much to take
0.5 mg
Before you take it
- No NIH/IOM Tolerable Upper Intake Level (UL) has been established for melatonin; standard OTC doses range from 0.5 mg to 10 mg but pharmacological effects are seen well below 1 mg.
- CYP1A2 major interaction: melatonin is primarily metabolized by CYP1A2; co-administration of fluvoxamine (Luvox) increases melatonin AUC ~17-fold and Cmax ~12-fold, such that a standard 1.5 mg dose can behave pharmacokinetically like 18–25 mg — risk of dangerous over-sedation; ciprofloxacin and estrogen-containing oral contraceptives also substantially elevate melatonin plasma levels.
- Anticoagulant interaction: melatonin has been shown to reduce plasma coagulation factors and may amplify the anticoagulant effect of warfarin and other blood-thinning agents; patients on anticoagulation therapy require INR monitoring if melatonin is added.
- Additive CNS depression when co-administered with benzodiazepines, z-drugs (zolpidem, zaleplon), alcohol, or opioids.
- Pregnancy and lactation: melatonin crosses the placenta and is excreted in breast milk; developmental safety data are insufficient and it is generally not recommended during pregnancy or breastfeeding without medical supervision.
- Daytime sedation and impaired alertness have been reported, particularly at doses above 2 mg; higher-end doses in common OTC products (5–10 mg) substantially increase next-day somnolence risk.
- Pediatric chronic use: long-term effects on pubertal timing have not been definitively ruled out; evidence base for extended use in children remains limited.
- OTC label accuracy concern: a 2023 analysis of 25 melatonin gummy products found actual content ranged from 74% to 347% of the labeled dose, and 26% of products also contained unlabeled serotonin.