Is E551 halal?

What is E551?

Silicon dioxide, or silica, is the same compound found in sand and quartz. The food grade is synthetic amorphous silica, made either by burning silicon chlorides in a hydrogen and oxygen flame (fumed silica) or by adding acid to a sodium silicate solution (precipitated silica or silica gel).

Why it's marked “Generally halal”

It is a mineral made from sand-based chemicals, with no animal material or alcohol involved. The only catch is its role as a carrier: it can hold colours, flavourings or emulsifiers, and those carried ingredients have their own origin. The silica itself is not a concern.

How to check the label

No check is needed for the silica itself. If a powder lists flavourings or emulsifiers next to E551, judge those ingredients separately or look for a halal certificate.

Where you'll find it

• table salt
• spice mixes
• powdered drink mixes
• grated cheese
• food supplements

Good to know

• In 2018 EFSA could not confirm the earlier “not specified” acceptable daily intake because of data gaps, including on nano-sized particles.
• In 2024 EFSA again found it not appropriate to set an acceptable daily intake, but saw no genotoxicity concern and no safety concern for infant foods at current exposure.
• A market check cited by EFSA in 2018 found E551 on about 5,000 EU products, roughly half of them food supplements.

Similar additives

• E171 Titanium dioxide Generally halal
• E339 Sodium phosphates Generally halal
• E450 Diphosphates Generally halal
• E500 Sodium carbonates (baking soda) Generally halal
• E460 Cellulose Generally halal
• E901 Beeswax Generally halal

See all 89 E-numbers in the halal checker

This list describes where additives usually come from. It isn't a religious ruling, and manufacturers can change their sources. Last reviewed: 14 October 2026.

Sources

1. EFSA re-evaluation of silicon dioxide E 551 (2018)
2. EFSA follow-up on E 551, including infant foods (2024)

Frequently asked questions