hormone · for jet lag
Melatonin
Melatonin is your body’s night signal. Taking it at bedtime where you land re-times your clock faster.
Say that in clinical terms
Melatonin is the hormone that signals biological night; taking it at the new destination's bedtime helps re-time the body's internal clock to the new time zone faster than it would re-align on its own.
How strong is the research?
In 257 doctors flying home from New York, none of three melatonin schedules beat placebo.
3 papers read, 2 supporting, 1 against.
Tested as: melatonin 0.5–5 mg taken close to the target bedtime at the destination (roughly 10pm–midnight local time), once daily for several days after arrival, on flights crossing 5 or more time zones — benefit is clearest for eastward travel and grows with more zones crossed, and is weaker for westward flights or short (2–4 zone) trips. Doses of 0.5 mg and 5 mg reduced jet-lag symptoms similarly; 5 mg produced somewhat faster sleep onset and better sleep quality than 0.5 mg, but doses above 5 mg showed no added benefit. A 2 mg slow-release form was less effective than an equivalent fast-release dose, suggesting a short, higher peak works better than a smoothed-out one.
How much to take
0.5–5 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.