Melasma

Melasma is a chronic pigmentation condition causing symmetrical brown or grey-brown patches, usually on the cheeks, forehead and upper lip. It is driven by UV exposure, visible light and hormones — pregnancy, the contraceptive pill and hormone therapy are common triggers — and it is far more common in women and in medium-to-dark skin tones. Daily broad-spectrum SPF 50 sunscreen, ideally tinted with iron oxide to block visible light, is the single most important intervention. Prescription treatments like hydroquinone, azelaic acid and tranexamic acid are used for stubborn cases. No oral supplement has strong evidence, and melasma frequently recurs with sun exposure.

Evidence synthesis: The evidence hierarchy for melasma is clear: rigorous photoprotection (broad-spectrum sunscreen with iron oxides for visible light protection) is the foundation with the strongest supporting data, followed by topical prescription agents like triple combination cream and oral or topical tranexamic acid. Oral glutathione has a small number of low-quality randomised trials suggesting mild lightening, but results are inconsistent, studies are short, and long-term safety data for high-dose use are lacking. Polypodium leucotomos extract has modest supporting evidence as an adjunct to sunscreen. Vitamin C and other antioxidants have mechanistic rationale but minimal direct trial evidence for melasma specifically.