E551Anti-caking Agent

Silicon dioxide

Learn what Silicon dioxide (E551) is, why it's added to food, whether it's safe, and which products contain it.

Low concern

What is Silicon dioxide?

The need for silicon dioxide arises from its high absorption capacity for vapors, gases, and even various impurities present in some food products. For example, it is used in beer because it absorbs large protein molecules responsible for causing cloudiness in the final product. This treatment does not affect the stability of the foam, color, or taste of the product.

Why is Silicon dioxide added to food?

Silicon dioxide (E551) is a anti-caking agent commonly found in: Processed cheese, spices, oil, butter, margarine.

Is Silicon dioxide safe?

Low concern

Since silicon dioxide is found in plants and drinking water, it is considered safe. It is known that the silicon we consume through diet does not accumulate in the body and is eliminated by the kidneys. According to EFSA, studies on animals showed no accumulation of silicon after the animals repeatedly consumed silica.

Is Silicon dioxide banned anywhere?

✓ Not currently banned in the EU or known to be restricted in other countries.

Common foods that contain Silicon dioxide

  • Processed cheese
  • spices
  • oil
  • butter
  • margarine

See the full list of foods that contain Silicon dioxide

How to spot Silicon dioxide on labels

Look for any of these names in the ingredients list:

  • E551
  • Silicon dioxide

Common misspellings to watch for:

  • silicon dloxide
  • silicon dioxide
  • sillcon dioxide
  • $ilicon dioxide
  • silieon dioxide
  • silicon dioxlde
  • sllicon dioxide

Better alternatives

• People with kidney conditions should avoid products containing silicon dioxide, as it can interfere with electrolyte balance and kidney function. • It is not recommended for people with respiratory conditions, as inhaling silica dust may irritate the respiratory tract. • Excessive use may lead to gastrointestinal issues such as constipation or bloating. • Avoid taking with other supplements that may affect mineral absorption, such as iron or calcium.

Explore homemade alternatives to processed snacks →

Also known as

  • silicon dloxide
  • silicon dioxide
  • sillcon dioxide
  • $ilicon dioxide
  • silieon dioxide
  • silicon dioxlde
  • sllicon dioxide

Scan products with BioBrief

Not sure if a product contains Silicon dioxide? BioBrief scans the barcode and instantly shows you every additive in the ingredients list — including E551 — with a plain-language explanation.

Frequently asked questions about Silicon dioxide

Is Silicon dioxide safe to eat?
Since silicon dioxide is found in plants and drinking water, it is considered safe. It is known that the silicon we consume through diet does not accumulate in the body and is eliminated by the kidneys. According to EFSA, studies on animals showed no accumulation of silicon after the animals repeatedly consumed silica.
Is Silicon dioxide banned anywhere?
Silicon dioxide is not currently banned in the EU or known to be restricted in other countries.
How do I spot Silicon dioxide on a food label?
Look for E551, Silicon dioxide in the ingredients list. It may also appear as: silicon dloxide, silicon dioxide, sillcon dioxide.

Ingredients change. Always check the actual product label before purchasing. Information on this page is for educational purposes only.