What is designed to protect the skin from the sun, but can be destroyed by large doses of UV light?

Melanin is a pigment produced by melanocytes in the skin that serves as a natural sunscreen by absorbing UV radiation and thereby protecting skin cells from damage. It acts as a barrier against the harmful effects of UV light, which can lead to skin cancer and premature aging. However, when the skin is exposed to large doses of UV radiation, it can overwhelm the protective effect of melanin, resulting in its breakdown and a reduction in its protective capacity. This makes the skin more susceptible to damage.

Coenzyme Q10, collagen, and vitamin D play important roles in skin health, but they do not primarily function as a protective barrier against UV radiation in the same way that melanin does. Coenzyme Q10 is an antioxidant, collagen provides structural support, and vitamin D is essential for various bodily functions but is synthesized in response to UV exposure.