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Yannis Lopez
Reviewed by Yannis Lopez · Nutrition Industry Veteran
Last updated: July 6, 2026
Skin & Hair Bones

Silica / Silicon

Silicon is essential for collagen synthesis and bone matrix formation — yet most "silica" supplements contain silicon dioxide, which has essentially zero bioavailability. The form you choose is everything with this mineral.

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your physician before starting any supplement.

Featured in: The Skin & Hair Stack
Overview

Silicon is the second most abundant element in the Earth's crust — and the third most abundant trace element in the human body. It plays structural roles in connective tissue that are only beginning to be fully understood. Silicon is incorporated into bone matrix, participates in the cross-linking of collagen and glycosaminoglycans (the structural proteins of cartilage, skin, and tendons), and appears to be required for prolyl hydroxylase activity — the same enzyme that Vitamin C activates in collagen synthesis.

The key distinction that most consumers miss: silicon (the mineral element, Si) and silica (silicon dioxide, SiO₂) are different things. Silicon dioxide — the same compound used as an anti-caking agent in powdered supplements and listed as an "inactive ingredient" — is essentially insoluble and has near-zero bioavailability. When you see "silica" on a supplement label, you need to check whether it's in a bioavailable form or just SiO₂ filler.

Further terminology note: silicone (the synthetic polymer used in medical implants and cookware) is entirely different — a manufactured polymer with no relevance to silicon nutrition. Don't let the similar names cause confusion.

The Bioavailability Problem — Why Form Is Everything
Most "Silica" Supplements Deliver Nothing

Silicon dioxide (SiO₂) — the form listed as "silica" in the majority of mineral supplements — is a polymerised, insoluble mineral with essentially zero oral bioavailability. Your body cannot extract usable silicon from it. A product listing "200mg silica (as silicon dioxide)" is delivering functional silicon about as efficiently as swallowing sand. The only forms your body can actually absorb are soluble orthosilicic acid (Si(OH)₄) and its stabilised derivatives.

Best: ch-OSA (BioSil)

Choline-stabilised orthosilicic acid — the gold standard for bioavailable silicon. Stabilising orthosilicic acid with choline prevents polymerisation in the bottle, delivering monomeric Si(OH)₄ that is immediately bioavailable. All human clinical trials on silicon and hair/skin use this form. 10mg silicon/day = 5 drops or 2 capsules of BioSil.

Good: Bamboo extract

Bamboo (Bambusa vulgaris or Phyllostachys species) has among the highest silicon concentrations in the plant kingdom (up to 70% dry weight as silica in some species). Bamboo extract releases soluble silicic acid during digestion with reasonable bioavailability. A practical middle-ground option if ch-OSA is unavailable or cost-prohibitive.

Caution: Horsetail extract

Equisetum arvense (horsetail) is the traditional herbal source of silica and contains reasonable silicon. However, it also contains thiaminase — an enzyme that destroys thiamine (Vitamin B1). Long-term or high-dose horsetail use risks thiamine deficiency. Only use standardised silica-only extracts with thiaminase removed, not raw horsetail powder.

Avoid: Silicon dioxide / silica (SiO₂)

This form appears in the majority of budget silicon supplements and multivitamins. It is insoluble, passes through the digestive tract unchanged, and provides no meaningful silicon nutrition. It is primarily used as a flow agent and anti-caking agent in powdered supplements — an excipient, not a nutrient. If a supplement lists only "silica" or "silicon dioxide" without specifying a bioavailable form (ch-OSA, orthosilicic acid, bamboo extract), assume it is SiO₂ and discard it.

Potential Benefits
Evidence using bioavailable silicon (ch-OSA):
  • Hair tensile strength: A 2007 RCT by Wickett et al. found that 10mg/day ch-OSA for 9 months significantly increased hair tensile strength and reduced breakage in women with fine hair. Hair cross-sectional area increased, and brittleness decreased. This is the most robust hair evidence available for any silicon supplement.
  • Skin elasticity and collagen density: Barel et al. (2005) found 10mg/day ch-OSA for 20 weeks produced significant improvements in skin surface and mechanical properties compared to placebo, with microrelief and skin roughness both improving. The proposed mechanism is silicon's role in activating prolyl hydroxylase for collagen synthesis.
  • Nail brittleness: Clinical observations and smaller trials suggest silicon supplementation reduces nail brittleness and breakage — consistent with its structural role in the keratin matrix, though the nail evidence is less robust than the hair and skin data.
  • Bone health: Epidemiological data (Jugdaohsingh et al., 2004) consistently associates higher dietary silicon intake with greater bone mineral density, particularly in premenopausal women and men. Silicon is incorporated into hydroxyapatite crystals in bone matrix and supports osteoblast differentiation. Clinical trial data for fracture prevention is limited but mechanistically well-supported.
Evidence limitations

The majority of silicon research uses ch-OSA specifically — results cannot be extrapolated to other silicon forms. Most trials are relatively small and short-term. Silicon's role in bone health is strongly supported epidemiologically but awaits larger intervention trials. Hair and skin results are the most consistently demonstrated clinical effects with ch-OSA.

How Silicon Works in the Body
Collagen Cross-linking

Silicon stimulates prolyl hydroxylase — the enzyme that adds hydroxyproline to collagen chains, enabling the cross-links that give collagen its tensile strength. This requires both Vitamin C and silicon as cofactors, making them complementary rather than redundant.

Bone Matrix Formation

Silicon is concentrated at sites of active bone formation. It is incorporated into the organic bone matrix alongside collagen and promotes osteoblast differentiation. Bone silicon content declines with age, correlating with reduced bone quality and density.

Glycosaminoglycan Stabilisation

Silicon interacts with glycosaminoglycans (hyaluronic acid, chondroitin, dermatan sulphate) — the structural molecules of skin, cartilage, and tendons. It forms cross-links between polysaccharide chains, contributing to the resilience and water-binding capacity of these tissues.

Dosage
ch-OSA (BioSil) — the researched dose
10 mg/day
As bioavailable silicon — 5 drops or 2 capsules
Bamboo extract
300–1,000 mg/day
Variable silicon content by product; check label for Si equivalent

Results require patience. Silicon acts through collagen and bone matrix remodelling — both slow processes. Wickett's hair study ran for 9 months; Barel's skin study for 20 weeks. Expect 3–6 months of consistent supplementation before evaluating results.

Pair with Vitamin C. Both silicon and Vitamin C are required for prolyl hydroxylase activity. Taking them together maximises the collagen synthesis benefit. See our Vitamin C guide for dosing.

For ch-OSA specifically: Take with or without food. The liquid drop form (BioSil) can be added to water or juice. Capsule forms are more convenient but check they specify "ch-OSA" or "choline-stabilised orthosilicic acid" — not simply "silicon dioxide."

Safety Profile

Silicon at dietary and supplemental doses has an excellent safety record. It is readily excreted by the kidneys when intake is adequate. There are no established upper tolerable limits for silicon in healthy adults, reflecting its low toxicity at supplemental doses.

Specific Considerations
  • Kidney disease: Soluble silicon is renally excreted. Individuals with impaired kidney function should use caution and consult their physician, as silicon may accumulate.
  • Horsetail (Equisetum) products: Raw horsetail contains thiaminase which can destroy Vitamin B1. Only use products that specify thiaminase has been removed or are standardised silica-only extracts. Avoid raw or crude horsetail powder.
  • ch-OSA contains choline: BioSil and similar ch-OSA products contain choline as the stabilising agent. This is a small but relevant amount — if you are already supplementing choline at high doses, factor this in. At standard doses this is not a concern.
  • Not the same as industrial silica: Crystalline silica (the industrial form inhaled in occupational settings) is a known carcinogen. Soluble orthosilicic acid as found in food and ch-OSA supplements is entirely different and has no association with any cancer risk at supplemental doses.
Smart Pairings
Vitamin C — Essential Collagen Cofactor
Silicon and Vitamin C are both required for prolyl hydroxylase — the enzyme that hydroxylates proline in procollagen chains, enabling collagen cross-linking. Taking them together addresses both cofactor requirements simultaneously. This is the most important pairing for anyone taking silicon specifically for skin, hair, or connective tissue support. See our Vitamin C guide.
Collagen Peptides — Structural Synergy
Silicon supports collagen synthesis from within; hydrolysed collagen peptides provide the amino acid building blocks (glycine, proline, hydroxyproline) needed for new collagen assembly. Together, they address both the substrate supply and the synthesis pathway simultaneously. For skin and hair goals, this combination has stronger theoretical support than either alone. See our Collagen guide.
Biotin — Hair & Nail Complement (Different Mechanism)
Biotin supports keratin infrastructure through B-vitamin-dependent carboxylase reactions; silicon supports the collagen matrix that surrounds hair follicles and nails. These are entirely different mechanisms, making them complementary rather than redundant. Biotin is more relevant for brittle nails; silicon more relevant for hair tensile strength and skin elasticity. Combining them covers both pathways for comprehensive hair and nail support.
Frequently Asked Questions
Why don't most silica supplements work?
Most contain silicon dioxide (SiO₂), which is insoluble and has essentially zero oral bioavailability — your body can't extract usable silicon from it. The only forms with meaningful absorption are choline-stabilized orthosilicic acid (ch-OSA) and, to a lesser extent, bamboo extract.
How long before I see results from silicon for hair or skin?
The clinical trials behind silicon's hair and skin benefits ran for 9 months (hair tensile strength) and 20 weeks (skin elasticity) using ch-OSA. Expect to need 3–6 months of consistent supplementation before evaluating results, since it works through gradual collagen and matrix remodeling.
Is horsetail extract a safe source of silica?
Only if it's a standardized extract with the thiaminase enzyme removed. Raw horsetail contains thiaminase, which destroys Vitamin B1 and can cause deficiency with long-term or high-dose use. Avoid crude horsetail powder and look for standardized silica-only products.
Is silica supplementation safe long-term?
Yes. Silicon has an excellent safety record at dietary and supplemental doses, and is readily excreted by the kidneys when intake is adequate. There's no established upper tolerable limit for healthy adults. People with impaired kidney function should still consult a physician first, since soluble silicon is renally cleared.
Sources & References
  1. Wickett RR, et al. Effect of Oral Intake of Choline-Stabilized Orthosilicic Acid on Hair Tensile Strength and Morphology in Women with Fine Hair. Arch Dermatol Res. 2007;299(10):499–505.
  2. Barel A, et al. Effect of Oral Intake of Choline-Stabilized Orthosilicic Acid on Skin, Nails and Hair in Women with Photodamaged Skin. Arch Dermatol Res. 2005;297(4):147–153.
  3. Jugdaohsingh R, et al. Dietary Silicon Intake Is Positively Associated with Bone Mineral Density in Men and Premenopausal Women of the Framingham Offspring Cohort. J Bone Miner Res. 2004;19(2):297–307.
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Vitamin C Collagen Biotin Vitamin D3
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