Nanotechnology-Based Strategies for Treating Skin Hyperpigmentation: A Review of Current Advances and Challenges.

Skin hyperpigmentation is a common dermatological condition characterized by excessive melanin accumulation in the epidermis, dermis, or both, resulting from disorders such as melasma, post-inflammatory hyperpigmentation, drug-induced hyperpigmentation, and solar lentigo. Conventional treatments are mainly based on tyrosinase inhibition; however, many depigmenting agents have limitations, including low stability, poor skin permeation, prolonged treatment durations, and adverse effects such as irritation and dermatitis. In this context, nanotechnology-based delivery systems have emerged as promising alternatives for the topical administration of depigmenting compounds. Therefore, this review discusses recent advances in nanotechnology-based strategies for treating skin hyperpigmentation, with a primary focus on lipid-based nanosystems, including liposomes, nanoemulsions, solid lipid nanoparticles, and nanostructured lipid carriers. A total of 33 studies published between 2000 and 2025 were analyzed. The reviewed studies demonstrated that nanoencapsulation may improve the physicochemical stability, enable controlled release, enhance skin permeation/retention, and increase the therapeutic performance of depigmenting agents while reducing toxicity and adverse effects. In vitro studies also reported enhanced tyrosinase inhibition, high cell viability, and increased accumulation of active compounds in different skin layers. Overall, nanotechnology-based delivery systems represent a promising and versatile approach for improving the efficacy and safety of topical treatments for skin hyperpigmentation.