Journal · Formulation · 7 min
Vitamin C: the four forms and where each belongs.
L-ascorbic acid, ascorbyl glucoside, sodium ascorbyl phosphate, and tetrahexyldecyl ascorbate. Same vitamin, different chemistry, different formulations.
The Biomedical Emporium® formulation desk
7 March 2026
L-ascorbic acid is the reference form. Strongest evidence, best studied, and the least stable. It needs low pH, dark packaging, and airless dispensing to hold its work.
Ascorbyl glucoside is stable, tolerable, and converts to L-ascorbic acid on the skin. It reads a hair below the reference form in most side-by-side studies, and above it on reactivity metrics. This is what sits in the Skin Biotic Cream C.
Sodium ascorbyl phosphate favours the acne side of things because it is antimicrobial. Tetrahexyldecyl ascorbate favours the lipid layer and behaves well in an oil phase. There is no single best form. There is a best form for what you are trying to do.
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