Need of UV protection and evaluation of efficacy of sunscreens

Sun exposure has been coupled with numerous types of acute and chronic reactions in skin, for example, sun burns, photoimmune suppression, photoaging, and skin cancer. In scrutiny of growing understanding of the potentially unfavorable long-term side effects of solar irradiation, there is a universal call for harmless and effective photoprotectants. Photoprotective agents are used for protection against ultraviolet (UV) radiations. In support of best photoprotective measures, now sunscreens are in great demand. Safeguard from UVB is quantified as a minimal erythema dose-based sun protection factor (SPF). UVA protection testing methods include evaluation of persistent pigment darkening (PPD) and critical wavelength. The rationale of this review is to present the contemporary information on the cutaneous pathophysiology of photooxidative stress, to study different UV filters with their UV spectrum and various commercially available sunscreens, with special emphasis on their active ingredients and SPFs. The characterization of different parameters to evaluate the efficacy of sunscreens, for example, SPF, immune suppression factor, photostability, and water resistance, have been described on the basis of findings from different researchers.