What substance in the skin helps protect against UV radiation?

Melanin is the substance in the skin that provides protection against UV radiation. It is a pigment produced by melanocytes, which are specialized skin cells. The primary function of melanin is to absorb and dissipate ultraviolet light, thereby reducing the risk of DNA damage caused by UV exposure. This protective mechanism helps prevent sunburn and lowers the likelihood of developing skin cancer.

Keratin, while important for the skin’s barrier function and overall integrity, does not play a direct role in UV protection. Collagen provides structural support and elasticity to the skin but does not have any protective qualities against UV radiation. Elastic fibers contribute to the skin's elasticity but are also not involved in UV defense mechanisms. Thus, melanin is uniquely suited for protecting the skin from the harmful effects of ultraviolet rays.