Oral Melatonin Does Not Darken Skin
No, taking melatonin tablets will not darken your skin—in fact, melatonin may actually lighten hyperpigmented skin in certain conditions. 1, 2
Evidence from Clinical Studies
The most direct evidence comes from a controlled study that followed patients taking oral melatonin for an average of 19 months using objective reflectometry measurements to assess skin color. This study conclusively demonstrated no significant change in skin color among patients receiving melatonin compared to controls. 1
Key Findings:
No darkening effect observed: Seven patients receiving oral melatonin showed no change in skin pigmentation over 19 months of monitoring 1
Potential lightening effect: In one specific case, melatonin actually lightened hyperpigmented skin in a patient with untreated adrenogenital syndrome, though it had no effect on idiopathic hyperpigmentation 2
Mechanism clarification: The effectiveness of melatonin in treating malignant melanoma is not related to suppression of normal melanogenesis (pigment production) 1
Current Therapeutic Uses for Skin
Interestingly, melatonin is actually being investigated and used for the opposite purpose—as a treatment for hyperpigmentation disorders rather than causing darkening:
Oral melatonin is listed among therapeutic agents for managing hyperpigmentation, alongside tranexamic acid and cysteamine hydrochloride 3
Melatonin participates in hypopigmentation processes in hyperpigmentary disorders like melasma 4
The hormone has antioxidant and photoprotective effects that help prevent UV-induced skin damage 5
Safety Profile
The American Academy of Sleep Medicine guidelines document that melatonin has an excellent safety profile, with the most common adverse effects being headache (0.74%) and dizziness (0.74%)—skin darkening is not listed among documented adverse reactions. 6