What is the primary effect of UV rays on the skin?

The primary effect of UV rays on the skin is stimulating melanin production. This process occurs as a natural defense mechanism against ultraviolet radiation. When the skin is exposed to UV rays, melanocytes, which are the cells responsible for producing melanin, become activated. Melanin acts as a pigment that absorbs UV radiation, helping to protect the deeper layers of the skin from damage caused by sun exposure.

In addition to the protective role, the increased melanin production often leads to tanning, which is a sign of the skin responding to UV exposure. While the enhancement of collagen production is important for skin health, it is not a direct primary effect of UV rays. UV exposure can actually lead to collagen breakdown over time, contributing to signs of aging. Similarly, while the heating of the dermis layer and hydration of dry skin can occur in various contexts, these are not the main or direct effects of UV rays on the skin. The stimulation of melanin production remains the most prominent and immediate response to UV exposure.