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Vitamin C (Sodium Ascorbyl Phosphate)

Sodium Ascorbyl Phosphate

A water-soluble, more stable form of vitamin C, made by attaching a phosphate group to the vitamin C molecule, used for antioxidant support in skincare.

Source

Vitamin C (ascorbic acid) bonded to a phosphate group

Used for

Antioxidant support

How it works

Vitamin C, built to stay stable.

Sodium ascorbyl phosphate is a derivative of vitamin C (ascorbic acid). A phosphate group is attached to the vitamin C ring, and the result is a water-soluble salt that is noticeably more stable than pure vitamin C.

That stability is the reason it is chosen. Pure ascorbic acid breaks down quickly in water-based formulas, while sodium ascorbyl phosphate holds up better. On the skin it is converted to free ascorbic acid by the skin's own enzymes, which is how it delivers vitamin C's antioxidant action.

In cosmetics its listed function is antioxidant, both protecting the formula and helping to defend skin against everyday oxidative stress. It is a gentle, water-loving form of vitamin C that suits serums, gels and masks, morning or night.

01
A water-soluble form of vitamin C, more stable than pure ascorbic acid
02
Converted to vitamin C by the skin's own enzymes
03
Antioxidant support for the skin and the formula

Questions

Is sodium ascorbyl phosphate real vitamin C?

It is a vitamin C derivative. A phosphate group is attached to ascorbic acid to make it more stable, and once applied it has to be converted into free ascorbic acid by enzymes in the skin. That is why it is often described as a form of vitamin C rather than pure vitamin C. (Spiclin et al., 2003; PubChem)

Why use sodium ascorbyl phosphate instead of pure vitamin C?

Mainly for stability. Pure ascorbic acid oxidises quickly in water, whereas sodium ascorbyl phosphate was developed as a more stable, water-loving form, so it suits well-made water-based formulas. (Spiclin et al., 2003; Dong et al., 2020)

How is it different from ascorbyl glucoside and ascorbyl palmitate?

All three are vitamin C derivatives, but each is made differently. Sodium ascorbyl phosphate carries a phosphate group and dissolves in water. Ascorbyl glucoside is vitamin C bonded to glucose, also water-soluble, while ascorbyl palmitate is vitamin C joined to a fatty acid, so it dissolves in oils. Each has its own entry in this dictionary. (PubChem; Spiclin et al., 2003)

Is there research on sodium ascorbyl phosphate on skin?

Yes. In a study on skin, a gel containing sodium ascorbyl phosphate was applied to the outer corners of the eyes, and fine lines looked softer, much as they did with a gel containing pure vitamin C. (Mohammadi et al., 2021)

Where it comes from

Sodium ascorbyl phosphate is the trisodium salt of ascorbyl phosphate: vitamin C (ascorbic acid) with a phosphate group attached to its ring. It dissolves readily in water. (PubChem; Spiclin et al., 2003)

The European cosmetic ingredient database lists its origin as plant or synthetic and its function as antioxidant, and notes that it appears in creams, masks, sun care and other skincare. (COSMILE Europe)

The research