Pollution and UV light can accelerate skin damage through oxidative (free radical) stress. Vitamin C is a potent antioxidant that supports healthier-looking skin and can help prevent visible skin damage like hyperpigmentation, dullness and uneven tone. Glycolic acid rapidly resurfaces and removes dead, dulling surface cells to reveal more radiant skin, and clears the way for vitamin C to penetrate skin more effectively. The Murad Environmental Shield Vita-C Glycolic Brightening Serum is formulated without fragrance and artificial colours; ideal for all skin tones and skin types, from oily to dry. Results after 1 week: Over 70% saw brighter, healthier skin After 4 weeks: 83% saw brighter, more radiant skin 86% saw healthier skin Murad is a PETA certified cruelty-free brand; they do not test any of their products on animals.