Beauty
L-Ascorbic Acid
Definition
The biologically active form of Vitamin C. The only form proven in peer-reviewed studies to stimulate collagen synthesis and inhibit melanin production when applied topically at concentrations of 10–20% and a pH below 3.5.
Why it matters for dupe shopping
SkinCeuticals C E Ferulic uses 15% L-ascorbic acid. Many budget alternatives use cheaper, less effective Vitamin C derivatives (ascorbyl glucoside, sodium ascorbyl phosphate). Always check the INCI list for 'ascorbic acid' specifically.