hormone · for low mood
Melatonin
A disrupted body clock goes with low mood, which is the loose reasoning behind the claim.
Say that in clinical terms
Melatonin regulates circadian rhythm, and disrupted circadian rhythm is associated with mood symptoms, which is the loose rationale for a mood effect.
How strong is the research?
No Benefit evidence
No improvement in depression or anxiety scores in postmenopausal women.
Low-quality evidence
1 paper read, 1 against.
Tested as: varies widely across small trials; no consistent dose/regimen studied specifically for low mood in a general population
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.