Demonstration of the dangerous nature of 'homemade' sunscreen recipes

Background Following a growing mistrust in a certain number of ingredients used by the cosmetic industry, it has become popular in recent years for consumers to make their own products at home. This trend now touches on all areas of the industry, but is especially found in the hygiene sector, with shampoos and toothpaste, and the care sector, with moisturizers and sunscreen, products. Objectives The objective of this study is to analyze sunscreen recipes found on the Internet and to assess their level of photoprotective efficacy. Materials and methods Fifteen Internet recipes were chosen, and then, the products were made in the laboratory following the protocols described. Using an in vitro method, the following efficacy indicators were determined for the preparations made: the Sun Protection Factor (SPF), the Production Factor in the UVA domain (PF-UVA), and the critical wavelength (λc ). Results Three of the 15 recipes studied do not contain any sunscreen and therefore constitute a major risk for users in case of exposure to the sun. The other 12 cannot be considered as sun protection products since all of them have an SPF under 6, the threshold value required in Europe. Conclusion The recipes that we collected on the Internet are very dangerous since some of them have no photoprotective effect whatsoever and most of them do not ensure a sufficient level of photoprotection for the persons using them.