E172 - Iron oxides and iron hydroxides

At a glance

These quick points explain what E172 does and where you might see it.

• Role: color additive for red, yellow, brown, and black tones
• Very stable to heat and light; does not dissolve in water or fat
• Commonly used on the surface of foods (e.g., sugar shells, decorations)
• Authorized in the EU; permitted for limited, specific uses in the U.S.
• Not intended as a dietary iron source

Why is Iron oxides and iron hydroxides added to food?

E172 is added to standardize and brighten color where plant-based colors may fade or shift. Because these pigments are highly stable and inert, they help products keep their intended appearance during cooking, storage, and transport. They do not contribute flavor and are typically used in coatings or surface decorations rather than throughout a food.

What foods contain Iron oxides and iron hydroxides?

Usage depends on local rules, but in the European Union, E172 is authorized as a color in various categories, and reported uses include sugar-coated confectionery (dragées), cake decorations, and surface coloring like cheese rinds or casings, among others.¹ In the United States, iron oxides are permitted only for limited, specified uses as a color additive exempt from certification; they are not broadly allowed to color all foods, and details are listed in the U.S. regulations.²

On labels, look for “E172,” “iron oxides,” or “iron hydroxides.” You’ll most often find them on shelf-stable decorations and coatings where strong, opaque color is desired.

What can replace Iron oxides and iron hydroxides?

Alternatives depend on the shade and the product:

• Browns and blacks: vegetable carbon, dark caramel
• Yellows to oranges: curcumin, annatto, paprika extract, beta-carotene, saffron
• Reds: beetroot red, cochineal
• White/opacity: calcium carbonates, or formerly titanium dioxide where permitted

Note that natural colors can be less light- and heat-stable than E172, and the final look may vary.

How is Iron oxides and iron hydroxides made?

Food-grade E172 pigments are made synthetically to ensure purity and consistency. They include three main types: iron oxide yellow (iron oxyhydroxide, FeOOH), iron oxide red (ferric oxide, Fe2O3), and iron oxide black (mixed ferrous–ferric oxide, Fe3O4). Browns are typically blends of these pigments.³

Manufacturers produce these pigments under controlled conditions, then wash, mill, and standardize them to meet strict identity and impurity limits set out in official specifications.³

Is Iron oxides and iron hydroxides safe to eat?

Based on a comprehensive review, the European Food Safety Authority (EFSA) concluded that E172 does not raise safety concerns at reported use levels and that establishing a numerical acceptable daily intake (ADI) was not necessary due to minimal gastrointestinal absorption of these insoluble pigments.¹ EU specifications also set tight limits on impurities (such as heavy metals) to ensure product quality and safety.³

In the U.S., iron oxides are permitted only for certain specified uses as color additives exempt from certification; this reflects a different regulatory approach to color approvals and not a finding of general hazard.²

Does Iron oxides and iron hydroxides have any benefits?

The benefit is technological: strong, opaque, and stable color that withstands processing and shelf life. Because these pigments are poorly absorbed, they are not intended or relied upon as a nutritional iron source.¹

Who should avoid Iron oxides and iron hydroxides?

Most people do not need to avoid E172. Individuals advised by a healthcare professional to limit color additives for medical or dietary reasons should follow that guidance. People seeking added dietary iron should not expect E172 to help, as these pigments are not a bioavailable iron source.¹

Myths & facts

• “It’s just rust, so it’s unsafe.” Fact: Food-grade iron oxides/hydroxides are manufactured under strict specifications for identity and purity; they are not scraped rust and must meet limits for impurities.³
• “It will boost my iron intake.” Fact: These pigments are minimally absorbed and are used for color, not nutrition.¹
• “It’s banned everywhere.” Fact: The EU authorizes E172 as a food color, while the U.S. allows it only for specified uses; regulations differ by region.²³

Iron oxides and iron hydroxides in branded foods

You’re most likely to see E172 in European sugar-coated confectionery (dragées and similar), cake-decorating dusts and coatings, and sometimes on the surface of cheeses or casings where permitted. Brands often reformulate over time, so the best way to check is to read the ingredient list for “E172,” “iron oxides,” or “iron hydroxides.”

References

Footnotes

1. Re-evaluation of iron oxides and hydroxides (E 172) as food additives — EFSA Journal. https://www.efsa.europa.eu/en/efsajournal/pub/4317 ↩ ↩² ↩³ ↩⁴ ↩⁵

2. 21 CFR 73.200 Iron oxides — U.S. eCFR (FDA). https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-73/subpart-A/section-73.200 ↩ ↩² ↩³

3. Commission Regulation (EU) No 231/2012: Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008 — EUR-Lex. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³ ↩⁴ ↩⁵