My diet:

E552 Calcium silicate

E552Anti-caking agentsOrigin: Mineral
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VeganYes

It is a calcium silicate mineral, including the synthetic powder.

Gluten-freeYes
HalalYes
KosherYes
KetoYes
Low-FODMAPYes
The short answer
Calcium silicate (E552) keeps powders free-flowing. The FDA caps it at 2 percent of a food, or 5 percent of baking powder. It is an allowed mineral, used like silicon dioxide.
Use in moderation

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

E-numberE552
Comes fromMineral
What it doesAnti-caking agents
Glycemic index—
Daily limitNot set
Also calledCalcium silicate, Synthetic calcium silicate

Rules by country

🇺🇸 US FDAApproved with limits
🇪🇺 European UnionApproved with limits
🇨🇦 Health CanadaApproved with limits
CaliforniaNo extra rules

The FDA allows calcium silicate, including the synthetic form, as an anticaking agent at no more than 2 percent of a food, except baking powder, which may contain up to 5 percent (21 CFR 172.410). The EU lists it as E552 and Canada permits it, both with limits. It is not absorbed as a nutrient. It leaves in the stool, which is the point of an anticaking mineral.

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

What is it?

The powder is white and fluffy. A small percent coated onto salt or a powdered drink stops clumps when the humidity rises.

Where it comes from: Calcium silicate is a chalky mineral powder, including a synthetic form, that coats other particles so they do not stick. Salt, baking powder and supplement capsules use it the way they use silicon dioxide. The FDA groups the synthetic powder with the mineral.

Why it’s in food

  • Keeps salt and seasoning blends pouring
  • Stops baking powder clumping, at up to 5 percent
  • Carries a powdered flavor
  • Stops supplement powders packing hard

Often found in

Table saltBaking powderPowdered drink mixesSpicesSupplement powdersShredded cheese

Also listed as: Calcium silicate, Synthetic calcium silicate

Health & gut impact

A percent capBenefit

The FDA rule is 2 percent of the food, and 5 percent only for baking powder. The amount has to be no more than the anticaking job needs.

21 CFR 172.410

Not a calcium supplementUnder study

The silicate does not dissolve the way calcium citrate does. Counting it toward a calcium goal would misread the ingredient.

Anticaking use of calcium silicate

What can I use instead?

Silicon dioxide

Ratio: A similar dusting

Best for: Spices and powders

Magnesium stearate

Ratio: More common in tablets than in kitchen salt

Best for: A capsule

Related

More anti-caking agents:

Calcium Phosphates (Tricalcium Phosphate) E341Calcium phosphates (E341) keep powders flowing, make baking powder rise and add calcium to plant milks. They're safe for most people, but phosphate additives add up, which matters for anyone with kidney disease.Use in moderationDimethylpolysiloxane E900Dimethylpolysiloxane (E900) is a food-grade silicone that stops frying oil from foaming. It sounds alarming, but it's used at a few parts per million and passes through the body unabsorbed.Use in moderationMagnesium carbonate E504Magnesium carbonate (E504) is a fine mineral powder that keeps table salt and spice blends free-flowing. It's vegan, gluten-free and safe at the small levels used in food.Generally safeMagnesium stearate E572Magnesium stearate (E572) is a fine powder that stops powders and supplement tablets from sticking to machines. It is approved in food and supplements, and it is vegan only when the fat behind it is plant-based.Generally safe

Common questions

Is calcium silicate safe in salt?

It is allowed for that job, at no more than 2 percent of the food.

Does it add calcium I can absorb?

Not in any useful way. It is there so the powder does not clump.

Is Calcium silicate safe?

Use in moderation (78/100). The FDA allows calcium silicate, including the synthetic form, as an anticaking agent at no more than 2 percent of a food, except baking powder, which may contain up to 5 percent (21 CFR 172.410). The EU lists it as E552 and Canada permits it, both with limits. It is not absorbed as a nutrient. It leaves in the stool, which is the point of an anticaking mineral.

Is Calcium silicate vegan?

Yes. It is a calcium silicate mineral, including the synthetic powder.

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Scientific sources & regulatory citations
  • 21 CFR 172.410 (US FDA)
  • EFSA OpenFoodTox: E552
  • 21 CFR 172.410
  • Anticaking use of calcium silicate

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