Ingredient
Allantoin
A quiet ingredient with a regulated strength, which is more than almost anything else in the same jar can say.
- INCI name
- Allantoin
- Also on labels as
- Aluminium dihydroxy allantoinate, Comfrey extract, Glyoxyldiureide, Symphytum officinale
- Found in
- cosmetics
Part of Eczema and atopic skin · Sensitive skin
Allantoin is one of the least argued-about ingredients in cosmetics. Nothing has been alleged about it, nothing has been withdrawn, and no campaign has been run against it.
It is here for a narrower reason: it is a drug active with a stated range, and that puts it in a very small group.
The number
The skin protectant monograph permits “allantoin, 0.5 to 2 percent”.
That is a tight range by the standards of that regulation, where Petrolatum runs to 100 percent and mineral oil to 100 percent. Allantoin works at low concentration and there is no benefit established above 2 percent, so the ceiling reflects evidence rather than caution about harm.
The consequence for a reader is the useful part. A product claiming to be a skin protectant states its allantoin concentration in a drug facts panel. A moisturiser containing the identical amount, making no such claim, states nothing. Same molecule, same jar, two different amounts of information, decided by what the box says the product is for.
That distinction runs through the whole category and is set out in the guide on which claims are regulated.
What it does
Two things, and they pull in the same direction.
It is a keratolytic at the gentle end: it helps the outermost layer of skin shed, which is why it appears in products for rough or flaking skin. And it is a humectant, holding water in that layer.
The combined effect is softening rather than treating. It is not an active in the sense that Salicylic acid is an active, and a product built on allantoin is a comfort product with a regulated ingredient in it.
Where it comes from
It occurs naturally in comfrey, Symphytum officinale, which is where it was first isolated and why some product copy leans on the plant. What goes into a modern product is manufactured rather than extracted, and it is the same molecule either way.
That matters because comfrey extract and allantoin are not interchangeable on a label. Comfrey extract contains allantoin in an unstated amount alongside everything else in the plant, including alkaloids that are the reason comfrey is not taken internally. Allantoin is the isolated compound at a stated concentration when the product is a drug.
Tolerance
Allantoin is among the least reactive ingredients in common use. It does not sting on compromised skin, it is not acidic, it has no meaningful contact allergy record, and it does not interact with anything else in a routine.
For reactive or atopic skin that is the whole recommendation. When a routine is being stripped back to find a trigger, allantoin is usually among the things that stay, alongside Colloidal oatmeal and Panthenol.
Reading for it
Look for the drug facts panel. If the product is a skin protectant, the active and its strength are stated there rather than in the ingredient list.
If there is no panel, allantoin will be in the ingredient list somewhere, and given its working range of 0.5 to 2 percent it will usually be near the end, where the order stops meaning anything. That is not a reason to distrust it; it is a reason not to read much into where it sits.
Sources
- 21 CFR 347.10: Skin protectant active ingredients US Food and Drug Administration, via eCFR · ecfr.gov Permits allantoin at 0.5 to 2 percent as a skin protectant active ingredient.
- 21 CFR 347.50: Labeling of skin protectant drug products US Food and Drug Administration, via eCFR · ecfr.gov Prescribes the statement of identity and the permitted indications wording for skin protectant products.