Is there clinical evidence that topical retinoids improve melasma?

Yes. Topical retinoids have been used in the treatment of many pigmentary disorders including melasma, solar lentigines, and postinflammatory hyperpigmentation. An evidence-based review found fair evidence to support the use of topical tretinoin as a monotherapy in the treatment of both melasma and solar lentigines. This study also found evidence to support clinical efficacy of topical tretinoin in a fixed, triple-combination therapy (hydroquinone 4%/tretinoin 0.05%/fluocinolone acetonide 0.01%) for the treatment of melasma.

Kang HY, Valerio L, Bahadoran P, Ortonne JP: The role of topical retinoids in the treatment of pigmentary disorders: an evidence-based review, Am J Clin Dermatol 10:251–260, 2009.