Comparing E551 - Silicon dioxide vs E572 - Magnesium stearate

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Overview

E551 - Silicon dioxide

Silicon dioxide (E551), also called silica, is a fine white powder used in many dry foods. It helps powders stay free‑flowing and acts as a carrier for flavors and vitamins. Regulators in the U.S. and EU allow its use in small amounts and consider it safe at current levels.

E572 - Magnesium stearate

Magnesium stearate (E572) is a white, waxy powder used in tiny amounts to keep foods and supplements free-flowing and to stop tablets from sticking to equipment. It is the magnesium salt of common food fatty acids and is widely approved by regulators in both the U.S. and the EU for use at good manufacturing practice levels. It does not add taste or color and has no meaningful nutritional effect.

Synonyms

E551

Silicon dioxide

Silica

SiO2

E572

Magnesium stearate

Functions

anticaking agent carrier

anticaking agent emulsifier

Origins

Products

Found in 241 products

Found in 1,447 products

Search rank & volume

#2490.6K / mo🇺🇸U.S.

#8923K / mo🇺🇸U.S.

Awareness score

×53.82

over-aware

×2.32

over-aware

Search volume over time

Interest over time for 4 keywords in U.S. during the last 10 years.

Interest over time for 2 keywords in U.S. during the last 10 years.

Popular questions

Is silicon dioxide safe?
Yes—food-grade silicon dioxide (E551), a synthetic amorphous silica used as an anti-caking agent, is permitted by regulators (e.g., FDA GRAS; EFSA found no concern at current uses) at typical food levels. This differs from inhaling crystalline silica dust, which is hazardous.
What happens if you eat silica gel?
Silica gel is an inert, amorphous silicon dioxide desiccant; if swallowed it usually passes through without being absorbed, though it can cause brief stomach upset or pose a choking risk. Indicator varieties (e.g., cobalt-dyed) aren’t meant to be eaten—seek advice if a child swallows a packet or a large amount.
Is silicon dioxide bad for you?
Not at the small amounts used in foods—E551 is considered safe and is largely not absorbed by the body. The main risk with silica is from inhaling crystalline silica dust, not ingesting food-grade amorphous silica.
Is silica bad for you?
In foods, amorphous silica (E551) used as an anti-caking agent is regarded as safe at permitted levels, and most ingested is excreted. Health concerns mainly relate to occupational inhalation of crystalline silica, which is hazardous.
What is silica gel?
Silica gel is a porous, amorphous form of silicon dioxide used as a desiccant to control moisture in packaging. It isn’t a food ingredient, and “Do not eat” labels are to prevent choking or misuse.