Pharmacology of Skin-Whitening Agents: Mechanisms Across Melanin Synthesis, Transfer, and Removal

step 1 — Melanin Synthesis Inside Melanocytes Show melanocytes in the basal epidermal layer. Indicate stimulation by ultraviolet (UV) radiation or inflammatory mediators. Inside the melanocyte, show melanosomes where melanin is synthesized from tyrosine via the tyrosinase pathway (tyrosine → DOPA → intermediates → melanin). Label melanosomes as the site of pigment synthesis and storage. Pharmacologic inhibition strategies: Tyrosinase inhibitors: hydroquinone, arbutin, kojic acid, azelaic acid, vitamin C UV protection: sunscreens Anti-inflammatory agents: topical corticosteroids, tranexamic acid Step 2 — Transfer of Melanin Pigment from Melanocyte to Keratinocyte Show melanosomes moving through melanocyte dendrites into neighboring keratinocytes. Inside keratinocytes, show melanin forming a supranuclear cap above the nucleus to protect DNA from UV radiation. Pharmacologic inhibition of transfer: niacinamide (Vitamin B3) Step 3 — Melanin Removal After Upward Migration and Shedding of Keratinocytes Show keratinocytes migrating upward through epidermal layers (basal → spinous → granular → stratum corneum). Show that melanin remains inside keratinocytes during migration. At the skin surface, show dead corneocytes being shed, representing natural pigment loss over time. Pharmacologic strategies for enhanced removal: Increase basal keratinocyte turnover: topical retinoids (adapalene, tretinoin, tazarotene) Increase surface shedding (exfoliation): physical methods (brushes, microdermabrasion) and chemical keratolytics (salicylic acid, glycolic acid, lactic acid) Cross-sectional view of epidermis highlights melanocyte and keratinocyte interactions. Color-coded labels and directional arrows show drug mechanisms and flow from synthesis → transfer → removal. Designed as a single infographic suitable for patients, medical students, and physicians to understand skin-whitening pharmacology in one glance. If you want, I can also rewrite it into a short, crisp figure legend that’s perfect for a publication or teaching slide. Do you want me to do that?