Herbal Topical Formulations for the Management of Melasma: Phytoconstituents, Mechanisms, and Recent Advances

Melasma is a chronic and relapsing hyperpigmentation disorder that predominantly affects sun-exposed areas of the face, leading to significant cosmetic concern and psychological impact. Conventional therapies such as hydroquinone, retinoids, chemical peels, and laser treatments often provide limited and temporary improvement, and are associated with irritation, photosensitivity, and risk of rebound pigmentation. In recent years, herbal topical formulations have gained attention as safer and effective alternatives or adjuncts in melasma management due to their multifunctional bioactivities and favorable tolerability profiles. This review highlights key phytoconstituents from medicinal plants such as flavonoids, phenolic acids, terpenoids, and alkaloids that exhibit tyrosinase inhibition, antioxidant, anti-inflammatory, and UV-protective effects relevant to melanin regulation. Mechanisms by which these compounds modulate melanogenesis include suppression of tyrosinase activity, down-regulation of melanogenic gene expression, scavenging of reactive oxygen species, and protection against UV-induced oxidative stress. Recent advances in formulation technologies such as nanoemulsions, liposomes, solid lipid nanoparticles, and hydrogels have further enhanced skin penetration, stability, and therapeutic performance of herbal actives. Clinical and preclinical evidence indicates promising results for formulations containing agents like licorice extract (glabridin), green tea polyphenols (EGCG), turmeric (curcumin), mulberry (oxyresveratrol), and others. While current data support the potential of herbal topical systems in improving melasma outcomes with reduced adverse effects, well-designed clinical trials and standardized formulation approaches are needed to validate long-term efficacy and safety. The integration of phytotherapy with modern delivery systems offers a compelling direction toward personalized and patient-friendly melasma management.