Antioxidants react with free radicals. An excess of free radicals is
associated with many conditions, and one of the most common is sunburn,
caused by excess UV exposure. Erythema is the medical term for skin redness. If Combray reduces concentrations of excess free radicals,
then a reduction in sunburn or erythema should be observed after
exposure to UV irradiation. (Note, this effect is not the same as a sunscreen,
and Combray should not be used as a substitute for sunscreen. See How to Use Combray.)
An
important piece of information for both effectiveness and safety is the
degree to which ingredients absorb into or through the skin (percutaneous means "through the skin"). Ideally, very little of a skin
care formulation passes through the skin to the bloodstream. It is
desirable however that a certain amount does penetrate the top-most
layers of skin, the stratum corneum and epidermis.
Grape seed oil consists of ca. 90% omega unsaturated fatty acids which are subject to photo-oxidation (light induced oxidation) when exposed to light and air. This is the process of oils going rancid - free radicals generated by light and air exposure react with the fatty acids. Antioxidant activity can be tested by comparing the relative rates of oxidation of oils in the presence of the antioxidant of interest.
