Abstract
Retinoids are central regulators of skin biology, influencing keratinocyte proliferation, differentiation, immune modulation, and barrier maintenance. Their therapeutic relevance has long been attributed to retinoic acid receptor (RAR)-mediated transcriptional activity; however, recent studies have revealed additional layers of regulation, including epigenetic modifications, kinase signaling networks, and interactions with the skin microbiome. These mechanisms not only refine our understanding of retinoid function but also inform strategies to overcome therapeutic limitations such as resistance, irritation, and systemic toxicity. Advances in medicinal chemistry have yielded synthetic retinoids with enhanced receptor selectivity, particularly for RAR-γ agonists such as trifarotene, as well as inhibitors of cytochrome P450-mediated retinoic acid metabolism, which sustain endogenous activity and mitigate resistance (DX314 and other RAMBAs). In parallel, the development of nanocarriers, stimuli-responsive gels, and other targeted delivery systems has improved drug stability, bioavailability, and tolerability. Together, these innovations underscore the evolving role of retinoid-based interventions in precision dermatology, providing opportunities to optimize treatment outcomes for acne, psoriasis, photoaging, and other dermatological disorders while addressing the shortcomings of earlier generations.