What tans the skin to protect it from the burning rays of the sun?

Melanin is the natural pigment produced by cells called melanocytes in the skin. When the skin is exposed to ultraviolet (UV) rays from the sun, it responds by producing more melanin, which leads to a tan. This tanning process occurs as a protective mechanism; melanin absorbs and dissipates UV radiation, thereby helping to shield the deeper layers of the skin from damage, including sunburn and potential skin cancers.

In contrast, collagen is a protein that provides structural support to the skin but does not play a role in tanning. Melatonin is a hormone primarily involved in regulating sleep cycles, not skin pigmentation. Keratin is a protein that forms the structural component of hair, skin, and nails but is not involved in the process of tanning or pigmentation. Understanding the role of melanin helps clarify how our body naturally protects itself from the harmful effects of sun exposure.