Cosmetic Safety Panel Reaffirms L-Ascorbic Acid and Five Vitamin C Salts as Safe in Skincare

The Expert Panel for Cosmetic Ingredient Safety, which runs the US Cosmetic Ingredient Review (CIR) programme, has published a re-review of vitamin C and its salts in the International Journal of Toxicology, online on 22 September 2026.

The review covers six ingredients: L-ascorbic acid, calcium ascorbate, magnesium ascorbate, magnesium ascorbyl phosphate, sodium ascorbate and sodium ascorbyl phosphate. After looking at safety data that had appeared since its original assessment, the panel concluded that all six are safe as cosmetic ingredients in the present practices of use and concentration described in its report. That keeps the verdict from the panel's first full assessment, published in 2005.

The new paper's summary does not list the fresh data or the concentrations now in use, and the full text sits behind a paywall, so the detail of what changed is not public in the abstract. The 2005 report gives useful background. It recorded L-ascorbic acid being used either at very low levels or in a 5 to 10 percent range in non-hair products, sodium ascorbyl phosphate at up to 3 percent and magnesium ascorbyl phosphate at up to 3 percent. It cited a repeat-insult patch test of a 5 percent ascorbic acid cream in 103 people that caused no sensitisation, and a 10 percent product that was non-irritating in a short cumulative patch test. It also cautioned formulators that certain metal ions can turn ascorbic acid from an antioxidant into a pro-oxidant.

Two points matter for serum buyers. First, CIR is an industry-funded programme with an independent expert panel; it is not a regulator, and its conclusions do not change Indian rules. Second, several derivatives now common in serums, such as 3-O-ethyl ascorbic acid, tetrahexyldecyl ascorbate and ascorbyl glucoside, are not among the six ingredients reviewed. Ascorbyl palmitate and related esters were assessed in an earlier, separate CIR report.

A safety conclusion is also not a statement about how well a product works, and individual skin can still react to an acidic or high-strength formula.