Which substance in the skin provides protection from UV radiation?

Melanin is the substance in the skin that plays a crucial role in protecting against ultraviolet (UV) radiation. It is a pigment produced by melanocytes, which are specialized cells located in the epidermis. When the skin is exposed to UV radiation from the sun, melanin absorbs this energy and dissipates it as heat, thereby reducing the risk of DNA damage that can lead to skin cancer.

The presence of melanin also contributes to skin pigmentation, which varies among individuals and provides a natural defense mechanism. Higher levels of melanin offer greater protection against UV radiation by providing a darker coloration that enhances this absorptive capability. This is why individuals with darker skin tones, which have higher melanin content, may have a lower risk of sunburn and other UV-related skin damage compared to those with lighter skin.

In contrast, while keratin is important for providing structural strength and waterproofing to the skin, and collagen contributes to skin elasticity and firmness, neither of these substances directly offers protection from UV radiation. Vitamin D, although vital for bone health and other physiological functions, is synthesized in the skin when exposed to UVB rays rather than protecting against UV exposure.