Since vitamin C serums are acidic, they are able to slough away dead cells from the skin’s surface, leaving it brighter and smoother. This in turn speeds up new cell regeneration. This acidity signals the skin to ‘heal’ itself by accelerating the production of collagen and elastin. Collagen is the protein fibers that make skin plump and prevent sagging; elastin are also protein fibers that help skin bounce back. Vitamin C is also used to reduce scarring, dark spots and other types of hyperpigmentation as well as brighten the skin, as it interferes with abnormal pigmentation through tyrosinase inhibition of the melanin pigment pathway. In other words, it’s able to fade brown spots without altering normal skin pigmentation. For daytime use, vitamin C functions as a potent antioxidant to protect your skin from free radicals and UV damage. At night, think of it as a way to repair the oxidative damage from the day. As an extra boost, try starting with a lemon water rinse to prep your skin with a light dosage of Vitamin C before applying your serum!