Allowed, with limits
Restricted in the EU
- What it can be used for
- Keeps the pH steady and makes alcohol undrinkable (the functions the EU ingredient database, CosIng, lists for it; a product may use it for any of them)
- CAS number
- 1310-73-2
Why it’s flagged
Allowed in EU cosmetics only with limits.
- Annex III entry 15a; products: (a) Nail cuticle solvent; (b) Hair straightener; (c) pH adjuster for depilatories; (d) Other uses as pH adjuster; Callosity softener/remover (entry 15d); max (a) 5%; (b) 2% (General use) and 4.5% (Professional use); Entry 15d: 1,5%; (b); 1. General use; 2. Professional use; (c) up to pH 12.7; (d) up to pH 11; 15 d Contains alcakali, Avoid contact with eyes; Keep out of reach of chindren ans; required warning: (a) Contains alkali; Avoid contact with eyes; Can cause blindness; Keep out of reach of children; (b) 1. Contains alkali; Avoid contact with eyes; Can cause bli. Source: EU Cosmetics Regulation, Annex III (restricted)
Annex III (restricted substances) or Annex V (preservatives) of the EU Cosmetics Regulation sets maximum amounts, allowed product types or required warnings.
What this page can’t tell you
These lists describe what a substance can do, its hazard. The risk from one product depends on how much is in it and how you use it, and the label doesn’t say how much.
Not being on a list doesn’t make an ingredient safe. It may never have been assessed.
Check your products
Check a whole labelProducts that list itEWG Skin DeepShop fragrance-free
“Products that list it” opens Open Beauty Facts, a free database anyone can edit.
Flagged the same way
Official lists checked September 2026. Spotted a mistake? Tell us.