The best studied antioxidants are vitamin C and vitamin E. The potency of an antioxidant is determined by its ORAC (oxygen radical absorbance capacity) value.
Vitamin C is one of the most potent, and frequently used antioxidants. It has been extensively studied and proven to have powerful beneficial effects on the skin. Vitamin C is found in high concentrations in the skin, but this decreases with age and sun damage., hence the benefit of topically applied product. Other than being an antioxidant, Vitamin C is a cofactor in collagen production, improves wound healing and inhibits melanin synthesis, thus improving fine lines and wrinkles, targeting pigmentation and lightening dark spots.
Vitamin E otherwise known as tocopherol is another well studied skincare ingredient. Besides being a potent antioxidant, it is know for its natural moisturising and anti inflammatory properties. Unlike vitamin C which can be used alone, vitamin E is best used in combination formulations.
When in combination antioxidants work synergistically multiplying their antioxidant potential.
A few other potent topical antioxidants include green tea polyphenols, resveratrol, ferulic acid and phloretin.
The list is growing, but the limitation is adding these ingredients to skincare products so that they remain stable and effective when used.