Aluminum Hydroxide
No meaningful concern for most people; irritation is possible but rare.
Also written as: Aluminium Hydroxide · Alumina Hydrate · Hydrated Alumina
What it is
Aluminum hydroxide is a white, water-insoluble inorganic powder. Its most common job in cosmetics is invisible to the consumer: it is one of the approved coatings applied to titanium dioxide and other mineral pigments to keep them dispersed and to damp down their photocatalytic activity. On its own it also acts as an opacifier, mild thickener and skin-protecting powder.
What it does well
Makes mineral pigments safer and more stable to use
It is one of the coatings the EU explicitly permits on nano titanium dioxide, where the coating is part of what keeps photocatalytic activity low. This is a well-defined technical role rather than a skin benefit.
Strong evidence
Worth knowing
Very poorly absorbed through skin
Aluminum hydroxide is essentially insoluble at skin pH, so it stays on the surface. It should not be confused with the soluble aluminium salts used at high concentration in antiperspirants, which is where the aluminium debate actually sits.
Matters most toPeople minimising total aluminium exposure for medical reasons, who may wish to discuss it with a clinician.
Where the EU stands
Concentration-restricted
Restricted since 2026 as an aluminium-containing ingredient. Regulation (EU) 2026/909, in force since 18 May 2026, added Annex III entry 381, a class entry covering aluminium-containing ingredients apart from named exceptions. Aluminium hydroxide does appear in one of those exceptions, Annex VI entry 27a, which is worth reading carefully: entry 27a regulates Titanium Dioxide (nano) as a UV filter and names aluminium hydroxide only as one of the permitted coatings on the particle. The exception therefore covers the aluminium carried on a coated nano titanium dioxide particle, not aluminum hydroxide used as an ingredient in its own right, which is caught by entry 381. The cap is expressed as aluminium rather than as the weight of the ingredient: 10.59% (as Al) in face leave-on products and 0.89% (as Al) in face and body rinse-off products. Products that do not comply may not be placed on the EU market from 1 January 2027, nor made available from 1 July 2028, so masks on sale today are unaffected.
Regulation (EC) No 1223/2009, Annex III entry 381 (added by Regulation (EU) 2026/909; printed as entry 379 in the Official Journal of 28 April 2026 and renumbered to 381 by the corrigendum at OJ L, 2026/90354, 5.5.2026); also named in Annex VI entry 27a as a permitted coating for Titanium Dioxide (nano) · source ↗
Sources (1)
Every link goes to the original: a journal, a PubMed record or an EU document.
- [1]Opinion on the safety of aluminium in cosmetic products - Submission IV (SCCS/1662/23)
SCCS - Scientific Committee on Consumer Safety, European Commission · 2024
The SCCS concluded that aluminium compounds are safe at the maximum levels it tabulated by product category, while noting that aluminium exposure aggregated across cosmetics and food may exceed safe limits for the most highly exposed consumers. These are the levels Regulation (EU) 2026/909 wrote into Annex III entry 381.
