E172 Iron oxides

E172ColorsOrigin: Mineral

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The short answer

Iron oxides (E172) are mineral pigments in red, yellow and black. They are allowed as food colors in Europe. US food use is narrow, and EFSA still wants better data on how fine the particles are.

70/100

Use in moderation

Safe in small amounts; may bother some people or raise blood sugar.

E-numberE172

Comes fromMineral

What it doesColors

Glycemic index—

Daily limitNot set

Also calledIron oxide, Iron oxides

Rules by country

🇺🇸 US FDAApproved with limits

🇪🇺 European UnionApproved

🇨🇦 Health CanadaApproved with limits

CaliforniaNo extra rules

Iron oxides are widely used as food colors in the EU. In the US, synthetic iron oxide is limited to uses such as sausage casings (up to 0.1%) and pet food. EFSA's 2015 review could not close the file on particle size, and no numerical daily limit was reset.

Daily limit: Experts haven’t set a number because normal food amounts are far below any level of concern.

What is it?

These are the same family of pigments as ochre and rust, cleaned up for food. Candy makers use them because the color survives heat and light better than beet or paprika.

Where it comes from: Food-grade iron oxides are purified iron minerals: red hematite, yellow iron hydroxide and black magnetite. They are not petroleum dyes.

Why it’s in food

Colors candy coatings
Tints sausage casings
Decorates cakes
Shades cheese rinds

Often found in

Coated chocolateSausage casingsCake decorationsPet foodCheese rindsSpice blends

Also listed as: Iron oxide, Iron oxides, Red iron oxide, Yellow iron oxide, Black iron oxide, CI 77491, CI 77492, CI 77499

Health & gut impact

Particle sizeUnder study

EFSA said the safety file for iron oxides was too thin on nanoparticles to reset a daily limit, even though the colors stay authorized.

EFSA re-evaluation of iron oxides and hydroxides (2015)

Iron intakeConcern

The iron added by E172 at food-color levels is small next to iron from meat, beans or fortified flour.

EFSA Panel on Food Additives (2015)

What can I use instead?

Paprika extract

Ratio: To shade

Best for: Red-orange foods

Beta-carotene

Ratio: To shade

Best for: Yellow-orange foods

More colors:

Allura Red AC (Red 40) E129Red 40 (E129) is a petroleum-based dye. It's legal in the US and EU, but European packages must carry a warning about hyperactivity in children, and California is removing it from school food.Best to avoid Amaranth dye E123Amaranth dye (E123) is a synthetic red that the US banned in 1976. Europe still allows tiny uses. It is not the amaranth seed sold as a gluten-free grain.Best to avoid Ammonia caramel (Caramel III) E150cAmmonia caramel (E150c) is the caramel class made with ammonia and no sulfite, common in beer. It is approved, but like cola caramel it can contain 4-MEI, which California lists under Proposition 65.Use in moderation Annatto E160bAnnatto (E160b) is a natural orange color from achiote seeds. It's what makes cheddar orange. It's safe and vegan, though it's one of the few natural colors that can trigger allergies.Generally safe

Common questions

Are iron oxides the same as food-grade iron supplements?

No. E172 is a color pigment. It is not meant as an iron supplement, and the body absorbs very little of it.

Is Iron oxides safe?

Use in moderation (70/100). Iron oxides are widely used as food colors in the EU. In the US, synthetic iron oxide is limited to uses such as sausage casings (up to 0.1%) and pet food. EFSA's 2015 review could not close the file on particle size, and no numerical daily limit was reset.

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Scientific sources & regulatory citations

21 CFR 73.200 (US FDA)
EFSA OpenFoodTox: E172
EFSA re-evaluation of iron oxides and hydroxides (2015)
EFSA Panel on Food Additives (2015)

INS 172 · CAS 1309-37-1