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Iron Oxides

Iron oxides

Well toleratedColourantcolourant

No meaningful concern for most people; irritation is possible but rare.

Also written as: CI 77491 · CI 77492 · CI 77499 · Iron Oxide Red · Iron Oxide Yellow · Iron Oxide Black

What it is

Iron oxides are inorganic pigments listed under three colour index numbers: CI 77491 (red, ferric oxide), CI 77492 (yellow, hydrated ferric oxide) and CI 77499 (black, ferrous-ferric oxide). Cosmetic grades are manufactured synthetically rather than ground from ore, which gives consistent colour and controlled purity. They are insoluble, extremely stable and produce the browns, terracottas and greys of clay masks and mineral make-up.

What it does well

  • Very low allergy risk compared with organic dyes

    As insoluble inorganic pigments they sit on the skin surface and are not appreciably absorbed, and contact allergy to them is rare. They are the standard choice for products aimed at sensitive skin.

    Strong evidence

Worth knowing

  • Purely cosmetic - they do nothing for the skin

    Iron oxides are there to make a mask look like clay or earth. That is not a safety problem, but it is worth knowing that a richer colour does not mean a more active product.

    Matters most toAnyone choosing a product on the basis of its colour.

Where the EU stands

No specific restriction

All three are on the EU positive list of permitted cosmetic colourants with no concentration limit, subject to the E 172 purity criteria. Only colourants on that list may be used in EU cosmetics.

Regulation (EC) No 1223/2009, Annex IV entries 135 (CI 77491), 136 (CI 77492) and 137 (CI 77499) · source ↗

Masks that contain Iron Oxides