Sodium ascorbyl phosphate

Formula context

"Vitamin C" on a cosmetic label is a category, not an ingredient. Several distinct substances sit inside it, and they behave differently in a formula.

Ascorbic acid

The unmodified form. Well studied, and notoriously unstable in water-based formulas — it oxidises, which is why ascorbic acid products often discolour over time.

Sodium ascorbyl phosphate

A phosphorylated derivative, as a sodium salt. More stable in water than ascorbic acid, and formulated at a different pH range.

Other derivatives

Magnesium ascorbyl phosphate, ascorbyl glucoside, tetrahexyldecyl ascorbate and others each have their own stability and solubility characteristics.

These are genuinely different ingredients. A product using one is not interchangeable with a product using another, and evidence generated for one does not automatically apply to the others.

That is why Amplified Glow naming the specific derivative matters. It lets you compare its serum against another product on a like-for-like basis, which "contains Vitamin C" does not.

The serum also discloses ferulic acid and vitamin E, both commonly formulated alongside vitamin C derivatives. See our ferulic acid page.

What the evidence can and cannot establish

Vitamin C and its derivatives are among the more heavily studied cosmetic ingredient families. That body of work is real, and it is also frequently over-read.

Two specific over-readings are worth naming. First, results for ascorbic acid are routinely presented as though they apply to its derivatives; they do not automatically. Second, results from studies using a known concentration at a known pH are presented as though they apply to a product that publishes neither.

For the Amplified Glow serum, both problems apply at once: we know the derivative but not the concentration, and not the pH. That is enough to say the product contains a named, stable vitamin C form. It is not enough to predict an outcome.