Sunscreen Challenges: Stability, Systemic Absorption, and Environmental Concerns

One of the key reasons for the currently perceived failure of sunscreens to protect against skin cancer by a large factor of protection, in studies done so far—seems to be related to the photostability of the sunscreens used in these studies. Today, sunscreen stability has been mostly well achieved in the case of the newer filters, but for the traditional filters like avobenzone which has excellent UVA filtering properties, physicochemical modifications to enhance filter stability may be the way forward. Sunscreen size is an important factor that decides both the potential for cutaneous penetration and therefore an impact on human health, as also the reactivity of these filters in the aquatic environment. A larger particle size for a given UV filter penetrates less and is less reactive. Reducing the overall load of sunscreens on the environment is an important ecological goal to achieve, and less reactive, durable UV filters, may provide an avenue to achieve this goal. Furthermore, sunscreen use in low UV index periods and usage of physical protection like clothing to cover the areas that can indeed be covered are human behaviours to be encouraged if we are to use sunscreen safely and sustainably. Addressing these sunscreen challenges involves increased awareness on the part of the physician for more effective patient counselling on using sunscreens.