Ascorbyl palmitate

Ascorbyl palmitate is made by joining ascorbic acid to palmitic acid, a fatty acid. The result is oil-soluble, so unlike most vitamin C forms it can be dissolved into anhydrous oils, balms and the oil phase of creams. It also appears in food as an antioxidant additive.

Its most reliable job in a cosmetic formula is protecting the product itself: it helps slow the oxidation of unsaturated oils, which is why you often see it low on the ingredient list of face oils and balms alongside tocopherol. Its performance as a skin-facing vitamin C is a different question — evidence that it converts efficiently to ascorbic acid in skin is limited, and it is generally considered less well supported than ascorbic acid or ascorbyl glucoside.

It is usually well tolerated and has no photosensitising reputation, but no antioxidant substitutes for sunscreen. If your goal is the look of uneven tone, choose a formula built around a form of vitamin C with stronger evidence, and patch test anything new.