E573 - Aluminium stearate

At a glance

• What it is: the aluminium salt of long‑chain fatty acids, mainly stearic acid.
• What it does: helps powders flow, prevents clumping, and supports stable fat or oil phases.
• Where it’s allowed: authorised as E 573 in the EU; in the U.S. it is permitted in some food‑contact materials rather than as a direct ingredient.
• Usual label names: aluminium stearate, aluminum stearate, E573.
• Dietary notes: derived from fats and oils; vegetarian and vegan status depends on the source of the fatty acids used.

Why is Aluminium stearate added to food?

Manufacturers use aluminium stearate for practical, texture‑related reasons. Its hydrophobic (water‑repelling) character can help keep powdered ingredients from caking and can help stabilize fat‑rich mixtures so they stay uniform during processing and storage. In the EU it is an authorised food additive with published identity and purity specifications, which define what the substance is and how pure it must be for use in food.¹

What foods contain Aluminium stearate?

Use is specialised and not widespread. In the EU, aluminium stearate is an approved additive (E 573), so you may see “aluminium stearate” or “E573” on ingredient lists of certain powdered or fat‑based foods.¹ In the United States, it is permitted in adhesives used for food packaging (an indirect food‑contact use), so it may help during packaging without being an intentional ingredient of the food itself.²

What can replace Aluminium stearate?

The best substitute depends on the job it is doing:

• To prevent clumping in dry mixes: silicon dioxide or flow‑aiding fatty acids
• To stabilize fat phases or aid dispersion: magnesium stearate or sodium, potassium and calcium salts of fatty acids
• To emulsify water and oil more strongly: lecithins or mono- and diglycerides of fatty acids
• For viscosity/texture in water‑based systems: xanthan gum

How is Aluminium stearate made?

Aluminium stearate is produced by reacting food‑grade fatty acids (mainly stearic acid) from edible fats and oils with aluminium salts or aluminium hydroxide to form the aluminium soap. EU specifications describe the substance as consisting predominantly of aluminium salts of stearic acid (often with some palmitic acid) and set limits for purity (such as aluminium content and contaminants).¹

Is Aluminium stearate safe to eat?

In the EU, aluminium stearate is permitted as E 573 and must meet strict identity and purity specifications before it can be used in food.¹ Safety assessments for aluminium in the diet consider overall intake from all sources. The European Food Safety Authority (EFSA) set a tolerable weekly intake (TWI) for aluminium of 1 mg per kilogram of body weight per week, covering total exposure from food, additives, and other sources.³ In the U.S., its use in food‑contact adhesives is regulated, with conditions intended to ensure safety under intended use.²

Does Aluminium stearate have any benefits?

Its benefits are technological, not nutritional. It helps manufacturers:

• Keep powders free‑flowing and reduce clumping
• Maintain stable textures in fat‑rich systems
• Improve processing, filling, and shelf‑life consistency

Who should avoid Aluminium stearate?

Most people do not need to avoid E 573 specifically. However:

• People who must limit overall aluminium exposure (for example, individuals with impaired kidney function, who clear aluminium less efficiently) should be mindful of total aluminium sources in their diet and environment.⁴
• If you follow a strict vegan diet, you may wish to check with manufacturers about the source of the fatty acids used to make the stearate (they can be from animal or plant fats).

Myths & facts

• Myth: Aluminium stearate is the same as aluminium metal.
  Fact: It is a compound made from aluminium and long‑chain fatty acids; its properties are very different from metallic aluminium.
• Myth: It’s only used in cosmetics.
  Fact: It is authorised as a food additive in the EU under E 573 and is also regulated for certain food‑contact uses in the U.S.
• Myth: Any aluminium compound in food is unsafe.
  Fact: Safety is managed by strict specifications and limits on total aluminium intake set by public health authorities.

Aluminium stearate in branded foods

On EU labels, look for “aluminium stearate” or “E573” in the ingredient list. In the U.S., you are unlikely to see it listed as an ingredient because its permitted role is mainly in food‑contact adhesives, not as a direct additive.² If you have dietary restrictions, you can contact the brand’s customer service to ask about the source of the stearic acid used.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — Specifications for food additives. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32012R0231 ↩ ↩² ↩³ ↩⁴

2. 21 CFR 175.105 — Adhesives (U.S. FDA). https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-175/section-175.105 ↩ ↩² ↩³

3. Safety of aluminium from dietary intake — EFSA Scientific Opinion (2008). https://www.efsa.europa.eu/en/efsajournal/pub/754 ↩

4. Toxicological Profile for Aluminum — ATSDR/CDC. https://www.atsdr.cdc.gov/toxprofiles/tp22.pdf ↩