What Is Silicon Dioxide?

Silicon dioxide, also called silica, is a natural compound found in foods, soil, and mineral water. It also appears as an additive in processed foods, labeled as E551.

Beyond its use in food, silicon dioxide is included in dietary supplements, often with claims that it enhances bone, skin, hair, and nail health. However, scientific backing for these benefits remains limited.

Potential Health Benefits

May Support Bone Health

Some research suggests silicon supplements could improve bone and cartilage strength. In one study, men with knee osteoarthritis who took 5 mg of silicon experienced reduced pain and improved function after 12 weeks. Women, however, saw no significant change.

May Improve Skin, Hair, and Nails

Small studies have linked silicon dioxide to enhanced skin elasticity, hair strength, and nail health. However, the sample sizes were small, and some lacked control groups. More research is needed to confirm these claims.

Limited Scientific Support

According to the European Food Safety Authority (EFSA), current evidence is insufficient to officially confirm the benefits of silicon dioxide for skin and bone health.

Sources of Silicon Dioxide

You can find silicon dioxide naturally in:

  • Grains: Wheat, rice, oats, barley

  • Vegetables: Potatoes, green beans, beets, carrots

  • Fruits: Apples, bananas

  • Water: Bottled spring and mineral water

Animal products such as eggs, meat, fish, and dairy also contain smaller amounts.

Uses in Food and Supplements

As a Food Additive (E551)

In food processing, silicon dioxide serves as:

  • Anticaking agent: Prevents clumping in dry powders

  • Anti-foaming agent: Reduces foam in liquids

Common products that may contain E551 include:

  • Powdered mixes

  • Cereals

  • Salt and sugar

  • Cheese and creamers

  • Chewing gum

  • Seasonings

This form of silicon is poorly absorbed by the body and mainly passes through the digestive tract without interacting much with bodily functions.

As a Dietary Supplement

The most absorbable form of silicon used in supplements is orthosilicic acid. Other forms include:

  • Monomethylsilanetriol (organic silicon)

  • Choline-stabilized orthosilicic acid

  • Orthosilicic acid-vanillin complex

Dosage and Supplement Forms

Recommended silicon doses vary depending on the form used:

  • Orthosilicic acid-vanillin complex: 10–18 mg/day

  • Monomethylsilanetriol: 7–10 mg/day

  • Choline-stabilized orthosilicic acid: 5–20 mg/day

Due to limited research, consult a healthcare provider before starting any silicon-containing supplement.

When choosing a supplement, look for third-party testing labels from organizations like NSF, USP, or ConsumerLab to ensure product quality.

Safety and Side Effects

There is no established acceptable daily intake (ADI) for silicon dioxide. However, the EFSA reports no known health risks when used as a food additive or in supplements. That said, evidence for long-term safety and efficacy is still lacking.

Caution

Always consult your healthcare provider before beginning any supplement regimen, especially if you have underlying conditions or take other medications.

Summary

Silicon dioxide is a compound found in nature and used in food processing and supplements. While it may offer benefits for bone and skin health, the scientific evidence remains inconclusive.

It's commonly used to prevent clumping in powdered foods and appears in several forms in dietary supplements. While generally considered safe, it's best to consult a healthcare provider before use.