3-O-Ethyl Ascorbic Acid
3-O-Ethyl Ascorbic Acid (EAC) is an etherified derivative of ascorbic acid in which an ethyl group is bound to the third carbon position of the vitamin C molecule. This modification makes it highly stable and soluble in both water and oil, overcoming a key limitation of pure ascorbic acid. It is claimed to be metabolized in the skin back into pure ascorbic acid, with an ascorbic acid content of approximately 86.4% — notably higher than the 50–60% typical of other vitamin C derivatives.
EAC is reported to provide antioxidant and anti-inflammatory effects, support collagen production, and deliver skin-brightening benefits. Clinical in-vivo data (2% EAC) supports improvement in skin tone and skin whitening. It also shows better skin penetration than some other vitamin C derivatives such as Ascorbyl Glucoside, based on animal study data.
Collagen-boosting and conversion-to-ascorbic-acid claims rely primarily on manufacturer data rather than independent clinical studies. Overall, the source characterizes EAC as "very promising but not fully proven."
