Understanding the Science of Silica Absorption
Silicon, or silica ($SiO_2$), is the second most abundant element in the Earth's crust, but its availability to the body is not universal. For the human body to effectively use silicon, it must be in a soluble, monomeric (single-molecule) form, primarily as orthosilicic acid (OSA). Many common sources, including most food and mineral supplements, contain silicon in highly polymerized (larger, complex molecules) or colloidal forms that the body finds very difficult to absorb. The degree of polymerization is inversely proportional to intestinal absorption, meaning the smaller the molecule, the more readily it is absorbed.
The Importance of Stability
One of the main challenges with achieving high absorption is stability. Orthosilicic acid, the bioavailable form, is stable only at very low concentrations. At higher concentrations, it quickly polymerizes into insoluble forms, which severely limits absorption. This is why many high-absorption supplements use stabilizing agents, such as choline or organic molecules, to prevent polymerization and keep the silica in its absorbable, monomeric state.
Top Contenders for Most Absorbable Silica
Monomethylsilanetriol (MMST)
Based on comparative studies, Monomethylsilanetriol (MMST) is one of the most highly absorbed supplemental forms of silica available. One study showed an absorption rate of 64% for MMST, which is higher than most other sources tested.
- Monomeric Structure: MMST is a single, organic silicon molecule, which allows it to be efficiently absorbed through the intestinal lining.
- High Stability: Unlike natural OSA, MMST is resistant to polymerization, maintaining its absorbable form even at higher concentrations.
- Commercial Availability: MMST is the active ingredient in patented formulas like Living Silica, which also boast an absorption rate of 64%.
Orthosilicic Acid (OSA) and its Stabilized Forms
Orthosilicic acid (OSA) is the naturally occurring bioavailable form of silicon. However, its instability at higher concentrations led to the development of stabilized versions for supplements.
- Natural OSA: Found predominantly in liquids like water and beer, natural OSA is readily absorbed. One study noted an absorption rate of approximately 43% for unstabilized OSA.
- Choline-Stabilized Orthosilicic Acid (ch-OSA): By stabilizing OSA with choline, manufacturers prevent premature polymerization. While effective, one study reported a lower absorption rate for ch-OSA (17%) compared to MMST.
Less Bioavailable Silica Forms
Not all silica sources are created equal in terms of absorption. Highly polymerized forms offer significantly less bioavailability.
- Colloidal Silica: This consists of fine solid particles suspended in water. Because of its polymerized nature, it is poorly absorbed, with one study showing only a 1% absorption rate.
- Diatomaceous Earth: Though a popular supplement, diatomaceous earth is primarily amorphous silicon dioxide. It is largely insoluble and poorly absorbed by the body, limiting its effectiveness as a source of absorbable silicon.
- Plant-Based Extracts (e.g., Horsetail): While plants like horsetail are rich in silica, their bioavailability varies. One study found horsetail extract to be less bioavailable than stabilized orthosilicic acid.
Comparison of Silica Bioavailability
| Form of Silica | Typical Absorption Rate | Stability | Common Supplement Form |
|---|---|---|---|
| Monomethylsilanetriol (MMST) | Up to 64% | Very High (Resists Polymerization) | Liquid Drops, Capsules |
| Orthosilicic Acid (OSA) | ~43% (Unstabilized) | Low (Polymerizes at High Concentrations) | Water, Beer |
| Choline-Stabilized OSA (ch-OSA) | ~17% (Stabilized) | High (Stabilized to Prevent Polymerization) | Liquid Drops, Tablets |
| Colloidal Silica | <1% (Poorly Absorbed) | High (Already Polymerized) | Gels, Suspensions |
| Diatomaceous Earth | Very low | High (Inert) | Powder, Capsules |
Choosing the Right Silica Supplement
To ensure you are getting the most absorbable silica, follow these guidelines for choosing a supplement:
- Prioritize Monomeric Forms: Look for supplements specifically containing MMST or stabilized orthosilicic acid, as these are formulated to be highly bioavailable.
- Verify Bioavailability Claims: Be wary of vague promises. Research specific studies or look for patented forms with proven absorption rates, like Living Silica.
- Choose Liquid Drops for Speed: Liquid forms are generally absorbed faster than capsules, but the chemical form (MMST, stabilized OSA) is more critical for overall absorption.
- Check Ingredients: Opt for products with minimal fillers, artificial flavorings, or unnecessary ingredients.
- Avoid Polymerized Forms: Steer clear of supplements relying on colloidal silica, silica gel, or diatomaceous earth for absorbability, as these have low efficacy.
Conclusion
While many forms of silica exist, research clearly indicates that monomeric, liquid forms—specifically Monomethylsilanetriol (MMST) and stabilized Orthosilicic Acid (OSA)—are the most absorbable. Unlike poorly absorbed options like colloidal silica or diatomaceous earth, these advanced supplements deliver a significant portion of their silicon content to the body, where it can be used to support bone health, skin elasticity, and collagen production. When selecting a supplement, prioritize bioavailability over raw silica content to ensure you reap the full health benefits. For further reading, a comparative absorption study published in the British Journal of Nutrition offers valuable insights into the absorption rates of various silica sources: https://pubmed.ncbi.nlm.nih.gov/19356271/.
Disclaimer: Consult a healthcare professional before starting any new supplement regimen.
