Well, research has found that when skin is excessively exposed to external aggressors (unprotected UV exposure and pollution, for example), its natural reserves of vitamin C become depleted4. It makes sense, then, that replenishing vitamin C levels in the skin can lead to a seemingly endless list of protective and restorative benefits. It’s important to find a stable, well-formulated topical serum, as the vitamin turns ineffective easily. You should also consider vitamin C supplementation, which has been shown to promote collagen production in the skin4.* Studies have found that topical application of polyphenols can help repair skin, protect it from sun damage, and even reverse signs of skin aging11 (like dark spots, fine lines, and wrinkles). When used in combination with sunscreen, green tea polyphenols, specifically, have has been shown to have an ultraprotective effect against UV rays12 and subsequent photodamage.