Melanin is the key pigment responsible for skin color, photoprotection, and the tanning response. Produced by melanocytes in the basal layer of the epidermis, melanin is synthesized in response to oxidative stress, especially UV exposure. This pigment is then transferred to keratinocytes, forming a natural shield that absorbs and dissipates UV radiation, protecting cellular DNA and supporting epidermal integrity. 

The tanning process is a physiological adaptation: increased melanin production (melanogenesis) leads to darker skin, enhanced protection, and a visible, healthy glow. A robust melanin network is fundamental for both skin defense and the visible effects of tanning.