Health Benefits and Uses of Silicon Dioxide (E551)

Silicon dioxide, commonly known as silicon or silica, is naturally found in foods and mineral water. It's also used in certain foods as an additive (with the code E551).

Silicon dioxide can be used as a main ingredient in dietary supplements or in small amounts to improve their stability. Silicon-containing supplements are generally sold with claims of improving bone, skin, hair, and nail health, but more research is still needed to support their benefits and overall safety.

May Support Bone Health

Silicon supplements may strengthen cartilage and bones.

In a study of the effects of silicon on people with knee osteoarthritis—a bone-related condition that causes joint pain—participants received either 5 milligrams of silicon or a placebo. There was no significant difference in pain in women who took the silicon supplement compared to the placebo. In men, silicon supplements improved pain, stiffness, and physical function after 12 weeks of intervention.

Can Improve Skin, Hair, and Nail Health

Early research suggests silicon dioxide may improve skin, hair, and nail health, though larger studies are still needed to confirm these claims.

In a study researching silicon supplements (containing 5 milligrams of silicon), participants experienced improved hair loss, hair quality, and skin and nail health after five months. However, the study size was small, and there was no control group (a group that didn't take the supplement) to compare the results.

Another study looked at the effects of a silicon dioxide supplement on skin health for 20 days. There was no difference in skin barrier function and hydration between participants who took the supplement and those who took the placebo. Participants who took the silicon supplement showed increased skin elasticity.

The European Food Safety Authority (EFSA) noted insufficient evidence to support the effects of silicon dioxide on bone and skin health. If you're interested in trying silicon dioxide supplements, it's important to consult with your healthcare provider to see if these supplements may be safe for you and your overall health.

Sources of Silicon Dioxide 

Silicon dioxide is found in soil and several foods. The most common sources of silicon dioxide include:

• Grains: Wheat, rice, oat and barley
• Vegetables: Green beans, potatoes, carrots, beetroots, and radishes
• Fruits: Bananas and apples

These foods are likely to contain higher levels of silicon dioxide. Foods such as eggs, meat, fish, and milk also contain silicon. You can also find silicon dioxide in bottled springs and mineral water.

Silicon Dioxide as a Food Additive

Silicon dioxide (E551) is mainly used in food products to prevent ingredients from sticking together (as an anticaking agent) and to reduce foam formation in liquids (as an anti-foaming agent). It's approved in the United States as a food additive (anticaking agent and stabilizer) by the Food and Drug Administration (FDA).

You can find silicon dioxide in certain products, such as:

• Dried powdered products
• Cereals
• Beverage whiteners
• Semi-hard and hard cheeses
• Oil sprays
• Chewing gums
• Sugar and syrups
• Salt and salt substitutes
• Seasonings

Silicon dioxide is one of the least bioavailable forms of silicon, which means it is not absorbed or used by the body as effectively as other forms. It is generally considered a compound with minimal absorption and mostly passes through the gastrointestinal tract.

Silicon Dioxide as a Supplement

Different types of silicon supplements exist, and orthosilicic acid is the most absorbable form. Orthosilicic acid is stabilized with different compounds (such as a methyl group, choline, or vanillin) and is generally used in dietary supplements. You may find silicon in the following supplement forms:

• Monomethylsilanetriol (organic silicon)
• Choline-stabilized orthosilicic acid 
• Orthosilicic acid-vanillin complex

Dosage

Silicon dioxide dosage can change based on the type of dietary supplement you're using. Consider the following dosage recommends for each type:

• Orthosilicic acid-vanillin complex: 10-18 milligrams (mg) of silicon per day for adults
• Monomethylsilanetriol (organic silicon): 7-10 mg of silicon a day
• Choline-stabilized orthosilicic acid: 5-20 mg of silicon daily

Research is very limited in establishing safe and effective doses of silicon, so talk to your healthcare provider or pharmacist before taking any supplements.

When buying a supplement, make sure the product is third-party tested. Unlike medications, the FDA does not regulate supplements, so their quality and safety can vary. Third-party testing confirms that the supplement contains the ingredients listed on the label and is free from harmful contaminants. Check for seals from reputable organizations such as NSF International, USP (United States Pharmacopeia), or ConsumerLab.

Is Silicon Dioxide Safe?

There is no established acceptable daily intake (ADI) for silicon dioxide. Although the evidence is limited, the EFSA states there are no signs of adverse effects of silicon dioxide for reported uses. More research is still needed to understand if this compound has health benefits. If you want to take silicon dioxide in supplement form, ask your healthcare provider if it's safe for you.

A Quick Review

Silicon dioxide (silicon or silica) is naturally found in soil, foods, and spring water. It is also added to food products as an additive (E551) and comes in supplement form.

Research claims silicon dioxide can improve bone, skin, hair, and nail health. While authorities state that the compound isn't considered toxic based on current evidence, widespread research is still needed to confirm these findings.