E-numbers / Other additives / E553a
also: Magnesium silicate E553a(i) · Magnesium trisilicate E553a(ii)
A mineral-derived powder that stops ingredients clumping together. Used in small amounts in powdered foods, tablets and table salt.
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EFSA found absorption very low and no genotoxicity indication, but said safety could not be fully assessed due to gaps in subchronic, chronic, carcinogenicity and reproductive data.
Why it’s worth knowing. EFSA found absorption very low and no genotoxicity indication, but said safety could not be fully assessed due to gaps in subchronic, chronic, carcinogenicity and reproductive data.
Magnesium silicate is a naturally occurring inorganic compound made up of magnesium, silicon and oxygen. It comes in two forms: magnesium silicate (E553a(i)) and magnesium trisilicate (E553a(ii)), which differ in their magnesium-to-silicon ratio. It is a fine white powder derived from mineral sources. It is chemically inert and is not meaningfully absorbed by the body during digestion.
It acts as an anti-caking agent and carrier. As an anti-caking agent it absorbs moisture and prevents powdered or granulated food ingredients from sticking together into lumps. As a carrier it helps distribute small amounts of other food additives or flavourings evenly through a food product.
Found in table salt and seasoning blends (to keep them free-flowing), powdered drink mixes, dried soups, baking powders, chewing gum, and as a carrier for food additives and flavourings. On a UK food label it appears as 'magnesium silicate' or 'E553a'.
The European Food Safety Authority re-evaluated E552 to E553b (the silicates group) in 2018. For magnesium silicate, the panel found no evidence of genotoxicity and no grounds to restrict it at the levels used in food. No numerical acceptable daily intake was needed because exposure from permitted uses was considered low and the substance is poorly absorbed. The panel flagged that some purity specification data were incomplete, but this was an administrative gap rather than a toxicological finding.
EFSA's ANS Panel found no genotoxic potential for magnesium silicate and concluded there was no safety concern at current permitted food use levels.
No numerical ADI was established for magnesium silicate; the panel noted the compound is poorly absorbed from the gastrointestinal tract and dietary exposure is low.
Magnesium silicate (E553a) is chemically related to talc (E553b), and the two are sometimes confused. Talc is a mixed magnesium silicate with a different mineral structure and a separate E number. Talc has attracted more regulatory scrutiny, particularly regarding asbestos-like mineral fibres in some industrial-grade forms. Food-grade talc and food-grade magnesium silicate must meet purity specifications that exclude asbestos fibres. The EFSA 2018 opinion covered both but treated them as distinct substances with separate assessments.
EFSA distinguished E553a (magnesium silicate) from E553b (talc) in its 2018 re-evaluation and assessed them separately; the asbestos-fibre concern applies specifically to talc, not to magnesium silicate.
No group is specifically advised to avoid magnesium silicate in food. People who must restrict magnesium intake for medical reasons (for example, certain kidney conditions) should be aware that it contributes a trace amount of magnesium, though amounts from food use are small. Look for 'magnesium silicate' or 'E553a' on the label.
Magnesium silicate is one of a family of mineral silicates that have been used in food for a long time. It is poorly absorbed and chemically unreactive in the body, which is why regulators have not set a numerical daily limit. The main scientific activity in this area was the EFSA 2018 group re-evaluation, which looked at all four silicates together. The conclusion was straightforward: no concern at food-use levels. The only technical notes were incomplete purity data for some forms, which is an administrative matter for manufacturers rather than a risk to shoppers.
No. Magnesium silicate is authorised in the UK under retained EU food law. It appears on the UK FSA approved-additives list with 'Authorised' status across England, Scotland and Wales.
They are different minerals. E553a is magnesium silicate; E553b is talc, a distinct mineral with a different structure. Talc has attracted more scrutiny over possible asbestos-like fibres in non-food-grade material. Food-grade versions of both must meet purity standards. EFSA assessed them separately in 2018 and found no concern for either at food use levels.
It is most commonly found in table salt and seasoning blends (to keep them free-flowing), powdered soup and drink mixes, chewing gum, baking powders, and food supplements. It is also used behind the scenes as a carrier for other food additives and flavourings.
Yes. Magnesium silicate is a mineral compound with no animal origin.
Last reviewed: 20 June 2026
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