The same is often true of hyaluronic and alpha-lipoic acids. “Hyaluronic acid, which is a highly effective humectant, and alpha-lipoic acid, a powerful antioxidant, both occur naturally in the body, but the reason we’re using synthetic versions is that there is simply not enough available,” says Marisa Vara Arredondo, the brains behind pHdriven skincare brand Phace Bioactive.