To help supplement the efforts of the skin’s built-in forces in the battle against free radicals (the skin-ravaging molecules stimulated by the sun, tobacco smoke and smog), antioxidants like vitamins C and E are being added to skincare products. So are green tea extracts, such as certain polyphenols, which are powerful studies show that these substances, applied directly to the skin, do eliminate the effects of free radicals, there’s little clinical evidence that most are effective at reversing existing signs of aging. Antioxidants are a good adjunct to sunscreen to help prevent further damage.