How to fight acute sun damage? Current strategies of the cosmetic market

Sunlight exposure can cause skin damage, like sunburn, skin dryness, wrinkles hyperpigmentation and skin sensitivity reactions. The use of aftersun products is a strategy that minimizes the visible signs and symptoms of sun-damaged skin, once that photo-damaged skin is more susceptible to inflammaging and oxidative stress events, affecting the skin's repair mechanisms. Aiming to unveil the active ingredients able to counteract acute sun damage, this work focuses on the characterization of the aftersun products market. Aftersun formulations currently marketed in Portuguese pharmacies were analysed concerning the composition described on the product´s label. Natural-derived extracts and pure compounds, as well as synthetic compounds, with anti-photodamage activity were found. The majority of the aftersun formulations contained natural-derived ingredients (> 95%), from terrestrial (77%) and marine (4%) sources. An in-depth examination of these compounds is also disclosed, revealing the top of the most used natural and synthetic ingredients present in aftersun products, as well as their mechanism of action. A critical appraisal of the scientific data supporting their efficacy, together with some considerations concerning structure-activity relationship studies were carried out. The presence of terpenoid, guanidine, ester, amide, ureido moiety, carboxylic acid and alcohol functions were found in the cosmetic ingredients most used in aftersun products, allowing the correlation with their bioactivities. In summary, this work provides an overview of the use of actives in commercial aftersun products in order to better understand the benefits associated with their use in cosmetic formulations, concomitantly identifying opportunities for innovation.