Human studies have convincingly demonstrated pronounced photo protective effects of 'natural' and synthetic antioxidants when applied topically before UVR exposure. Particularly with respect to UVB-induced skin damage such as erythema formation, the photoprotective effects of antioxidants are significant when applied in distinct mixtures in appropriate vehicles. One of the basic criteria for cosmetic and personal-care formulations is for them to have a shelf life sufficient enough to ensure product quality when purchased within a reasonable period of time. The ability of a product to resist oxidation is an important component of customer satisfaction. A stable formula will help ensure that the desired functionality and appearance of the product will not be significantly altered over time because of exposure to air. Oxidation and rancidity are primary adversaries to the cosmetic formulator. They have been and will continue to be a challenge in formulating.
Linoleic acid is as part of the upper skin (stratum corneum) vital for the skin's barrier function and exhibits important skin-care and restorative properties.