Derma Co Discount: Get Up To 20% OFF On Vitamin C Range using the latest coupons, deals & offers from CouponZania. The Derma Co. 20% Vitamin C Serum is just what your skin needs for a glow that makes heads turn. It’s time to bid goodbye to blemishes, pigmentation, dark spots, and uneven skin tone. The antioxidant properties of Vitamin C protect against UV-induced photodamage, while Hyaluronic acid keeps the skin cool and hydrated. In addition, vitamin C in 3-O-Ethyl Ascorbic Acid form has an immense brightening effect.