Skin photodamage and lifetime photoprotection

Ultraviolet (UV) radiation is a very small part of the electromagnetic radiation spectrum, released and transported from the source in the form of photons. Disposal of these photons within the skin causes cutaneous photodamage, which leads to clinical, histologic, and biochemical changes. Aging is a complex process characterized by cellular attrition, decreased cellular reserve capacity, and compromised ability to perform normal cellular function. Intrinsic aging, which steadily develops with time, is linked to chronologic age; it is the result of a genetic program. Photoaging, on the other hand, develops as a consequence of UV radiation-induced degenerative changes in the skin. Intrinsic aging is a universal, inevitable process, whereas photoaging is neither universal nor inevitable and can be prevented. UV radiation can also suppress the immune system in both local and systemic way and lead to simultaneous and sequential biochemical events that ultimately cause photocarcinogenesis. Therefore, everyday use of products that protect against UV radiation is necessary to prevent acute and long-term photodamage (clinical and cellular changes) leading to photoaging, photoimmunosuppression, and photocarcinogenesis.