What are the Side Effects of Silicon Dioxide Supplements?

January 10, 2026 •

4 min read

According to the European Food Safety Authority (EFSA), food-grade silicon dioxide, or amorphous silica, is generally considered safe for consumption. However, as with any supplement, some individuals may experience side effects from silicon dioxide supplements, especially those with sensitivities or underlying health conditions.

Quick Summary

This article explores the potential side effects associated with ingesting silicon dioxide supplements, covering common digestive issues, allergic reactions, and the important distinction between the supplement form and dangerous crystalline silica dust.

Key Points

Generally Safe for Oral Consumption: The amorphous form of silicon dioxide used in supplements is considered safe by regulatory bodies like the FDA and EFSA within approved limits.
Potential Digestive Issues: Some individuals may experience mild gastrointestinal side effects, such as upset stomach, bloating, or gas, particularly with higher doses or sensitivities.
Rare Allergic Reactions: Although uncommon, allergic reactions like rashes, hives, or swelling of the face can occur in sensitive people.
Amorphous vs. Crystalline is Key: Dangerous respiratory diseases like silicosis are caused by inhaling industrial-grade crystalline silica dust, not from ingesting food-grade amorphous silicon dioxide.
Long-Term Research is Needed: Concerns regarding the long-term effects of ingesting nanoparticle-sized silica have been raised by regulatory bodies like the EFSA, though oral toxicity is generally considered low.
Not a Bioavailable Form: Silicon dioxide is one of the less absorbable forms of silicon, and most of it is excreted by the kidneys.
Check Other Ingredients: Side effects could be caused by other additives in a supplement, not just the silicon dioxide.

Understanding Silicon Dioxide in Supplements

Silicon dioxide (SiO2) is a natural compound made from silicon and oxygen, two of the most abundant elements on Earth. In its amorphous, or food-grade, form, it is widely used in the supplement and food industries as an anti-caking agent, preventing powdered ingredients from clumping together. It is also found naturally in certain plant-based foods, including whole grains, green beans, and leafy vegetables. While silicon dioxide is often marketed in supplements for hair, skin, and nail health, its effectiveness and the precise mechanisms within the human body are still areas that require more research. The vast majority of orally ingested silicon dioxide is minimally absorbed and is efficiently excreted by the kidneys in healthy individuals, which is why it is considered safe in small, regulated amounts.

Gastrointestinal Side Effects

Though uncommon, some people may experience mild gastrointestinal distress when taking silicon dioxide supplements. These effects can include:

Upset Stomach: Nausea or general stomach discomfort can occur, especially in sensitive individuals.
Bloating and Gas: Some reports suggest bloating and increased gas, particularly when taking larger doses.
Constipation: Altered bowel movements, such as constipation, have been linked to some supplements containing silica, possibly due to the compound's absorbent properties.

While these symptoms are typically not severe, they are worth monitoring. It is important to differentiate between an individual sensitivity to the additive itself and a reaction to other ingredients in a multi-component supplement.

Allergic Reactions and Sensitivities

Allergic reactions to silicon dioxide are possible, though they are rare. Individuals with pre-existing allergies or sensitivities may be more prone to adverse effects. Symptoms of an allergic or sensitive reaction can include:

Rashes and Hives: Skin reactions, such as rashes and hives, have been reported in sensitive individuals.
Swelling: Swelling of the face or other parts of the body can occur in rare cases.
Respiratory Symptoms: Less commonly, symptoms such as sneezing, a runny nose, coughing, or wheezing may be reported.

If any of these symptoms appear, it is important to discontinue use and consult a healthcare professional. For those with a known history of allergies, checking the supplement label carefully for all ingredients is a crucial step.

The Critical Distinction: Amorphous vs. Crystalline Silica

A significant source of confusion and concern regarding the safety of silicon dioxide stems from the difference between amorphous and crystalline forms. This distinction is critical for understanding the true risks.

Amorphous Silicon Dioxide: This is the type of silica used in food and supplement products. It is considered safe for oral consumption in regulated amounts by health authorities like the FDA. It is minimally absorbed and excreted, and does not pose the serious health risks associated with the crystalline form.
Crystalline Silica: This form is found in sand, quartz, and other minerals and is used in industrial applications such as mining, construction, and glass manufacturing. The primary danger comes from inhaling the fine dust of crystalline silica over a prolonged period, which can cause serious and potentially fatal lung diseases like silicosis, chronic obstructive pulmonary disease (COPD), and lung cancer. It is important to emphasize that this risk applies to occupational inhalation, not oral ingestion of food-grade supplements.

Research and Long-Term Considerations

While acute side effects from food-grade silicon dioxide are rare, some research suggests the need for caution regarding long-term ingestion, particularly concerning nanoparticles. Animal studies have shown that high levels of nanoparticle exposure can cause gut inflammation, although the findings are not consistently replicated in humans. Organizations like the EFSA have expressed concerns about nanoparticle sizes, as long-term safety data are still lacking, and some manufacturers do not specify the particle size of their silica. Until more extensive human studies are conducted, consuming silicon dioxide within regulated amounts is considered the safest approach.

Comparison of Silicon Dioxide vs. Other Supplement Fillers


Feature	Silicon Dioxide (Amorphous)	Magnesium Stearate	Microcrystalline Cellulose
Primary Use	Anti-caking agent, prevents clumping	Lubricant, aids manufacturing	Binder, filler, disintegrant
Common Side Effects	Mild digestive upset, rare allergic reactions	Possible digestive issues, may affect nutrient absorption	Potential laxative effect, gas, bloating
Safety Profile	Considered safe by FDA and EFSA in regulated amounts. Low toxicity.	Widely used but some concerns exist regarding long-term, high-dose ingestion.	Generally safe, but can cause digestive upset.
Absorption by Body	Minimal absorption; excreted via kidneys.	Can potentially coat ingredients, impacting absorption.	Passes through the digestive tract largely undigested.
Particle Size Concern	Nanoparticle size concerns raised by EFSA, but oral toxicity is low.	Concerns focused on impact on nutrient absorption and potential long-term effects.	Generally not a particle-size concern for ingestion.

Conclusion

For the average consumer taking a regulated dietary supplement, the risk of serious side effects from amorphous silicon dioxide is extremely low. The compound is widely recognized as safe in the small quantities used to prevent caking. However, individuals who are particularly sensitive, have underlying digestive conditions, or are concerned about nanoparticle research should consult a healthcare provider and monitor their body's response. The serious health risks widely publicized, such as silicosis, are tied to the inhalation of crystalline silica in industrial settings, not the oral consumption of food-grade silicon dioxide. As research continues to evolve, especially concerning nanoparticles, staying informed and using supplements responsibly remains the best course of action.

Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult a healthcare professional before starting any new supplement.

Frequently Asked Questions

No, the amorphous silicon dioxide used in dietary supplements is considered safe by regulatory bodies like the FDA when consumed in regulated amounts. The severe health risks are associated with inhaling crystalline silica dust in occupational settings, not oral ingestion.

While uncommon, some people with sensitive digestive systems may experience mild gastrointestinal issues, including upset stomach, bloating, or gas, especially from high doses.

Amorphous silica is the food-grade form used in supplements and is safe for consumption. Crystalline silica is an industrial form found in materials like sand and quartz, and inhaling its dust can cause serious lung disease.

Allergic reactions to silicon dioxide are rare, but possible. Symptoms may include a rash, hives, or swelling. Individuals with known sensitivities or allergies should exercise caution.

Silicon dioxide is used in supplements and powdered food products as an anti-caking or flow agent. It prevents powders from clumping together and ensures a consistent texture.

Long-term research on the effects of orally ingesting silicon dioxide, particularly nanoparticles, is limited. Regulatory authorities like the EFSA have called for more studies, though its oral toxicity is currently considered low.

The FDA requires that silicon dioxide, also known as silica, synthetic amorphous silica (SAS), or E551, be listed on a supplement's ingredient label.