Regena S2 Pro contains 30% stabilised vitamin C in the form of ethyl ascorbic acid, one of the most stable and efficient known forms of ascorbic acid. Ethyl ascorbic acid absorbs easily into the skin to deliver the antioxidant and anti-inflammatory power of vitamin C deep into the epidermis and helping to increase skin firmness, help fight acne-causing bacteria, brighten, and leave skin with a slight glowy sheen.