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Silicon

Also known as: Silica, Silicon dioxide, Orthosilicic acid, OSA

The bone-and-connective-tissue mineral — real collagen biology, with hair-skin-nails evidence that is promising but partial.

Mineral specimens, neutral tablets, and a measuring spoon
Editorial illustration

Silicon has plausible roles in connective tissue and bone, but no U.S. intake requirement or clear deficiency syndrome has been established. Small trials of a specific bioavailable form report bone-marker and cosmetic outcomes; they do not validate every silica, bamboo, or horsetail supplement.1, 3

  • Trace mineral concentrated in bone and connective tissue1, 3
  • Bioavailable form: orthosilicic acid (ch-OSA in supplements)1, 3
  • Best evidence: bone collagen and density markers1, 3
  • Hair/skin/nail trials modest; deficiency essentially unknown1, 3

What is Silicon?

Silicon is the mineral your connective tissue is quietly built from. Between the calcium crystals of bone and the collagen fibers of skin sit silicon cross-links — the molecular rivets that give connective tissue its strength and flexibility. The supplement industry knows it mainly from hair-skin-nails products, where the evidence is modest; the more solid science is in bone, where trials in osteopenic women show measurable collagen and density responses. Silicon's profile is unusual: a mineral with genuinely important biology, no deficiency epidemic, and a supplement niche that oversells the cosmetic angle while underselling the skeletal one.3, 1

Where it comes from

Natural sources

  • Dietary sources: whole grains, green beans, bananas, mineral water (as orthosilicic acid)
  • Body contains ~1–2 g, concentrated in aorta, trachea, bone, skin, and hair
  • Absorbed as orthosilicic acid; polymeric silica is poorly absorbed

How it's made

Supplement forms: choline-stabilized orthosilicic acid (ch-OSA), horsetail extract, and colloidal silica.

What it does in products

  • Collagen and elastin cross-linking
  • Bone mineralization support (with calcium and vitamin D)
  • Prolyl hydroxylase cofactor in collagen synthesis
  • Hair and nail keratin structure support

Benefits

Bone density and collagen markers

moderate evidence

Trials of ch-OSA in osteopenic women report increased bone-collagen markers (P1NP) and, in some studies, improved femoral bone density.1, 3

Human and observational evidence supports a role in bone and collagen biology, but fracture outcomes and an established intake requirement are lacking.

Skin elasticity

limited evidence

Small trials report improved skin roughness and brittleness scores with ch-OSA supplementation.2, 3

The positive cosmetic evidence comes from small trials of a specific choline-stabilized orthosilicic-acid preparation.

Hair and nail strength

limited evidence

Trials show reduced nail brittleness and improved hair tensile strength; effects are modest and the data are limited.2

Hair tensile-strength and nail-brittleness findings are formulation-specific and do not establish treatment of hair loss or nail disease.

Evidence scope and limitations

The review covers dietary silicon and choline-stabilized orthosilicic acid; polymeric silica, horsetail, bamboo, and topical silica are not treated as bioequivalent.

  • No U.S. recommended dietary allowance or well-defined human deficiency syndrome has been established.
  • Most cosmetic trials are small and tied to one proprietary, bioavailable formulation.

Evidence last checked: 2026-09-26

Side effects & safety

GI upset (uncommon)Mild at standard doses.
Kidney-stone concern with horsetail-derived silica (rare)Horsetail's high silicon plus other constituents; ch-OSA is preferred.

Safety considerations

  • Safe at dietary and standard supplement levels.
  • Aluminum — silicon may reduce aluminum absorption (a proposed benefit)
  • No significant drug interactions established
  • Not for: Kidney disease (monitor with high-dose supplements)
  • Not for: Avoid horsetail preparations with thiamine deficiency (horsetail contains thiaminase)
1

Amounts studied & product use

These figures describe research or common product use, not a personal dose or treatment recommendation.

In supplement studies and products

Small bone and cosmetic trials use specific bioavailable preparations such as choline-stabilized orthosilicic acid, often supplying roughly 5–10 mg elemental silicon daily. There is no U.S. RDA, and these amounts do not validate variable horsetail, bamboo, or silica products.

In skincare studies and products

Topical silica is generally used for texture, slip, or oil absorption rather than as the oral orthosilicic-acid intervention studied for connective-tissue outcomes.

2, 1

Regulatory status

  • Sold as a dietary supplement; silicon dioxide is GRAS as a food additive.
  • GRAS (generally recognized as safe) for food use.
  • INCI name on cosmetic labels: Silica.
  • Assessed as safe in cosmetics.
4

The orthosilicic acid question

Only monomeric orthosilicic acid is absorbed; polymeric forms (plant silica, colloidal silica) must first be broken down — inefficiently in the human gut. That is why supplement form matters: ch-OSA delivers the bioavailable monomer directly, which is the form used in the positive trials. Horsetail and bamboo supply silica polymers with uncertain conversion.

3, 1

Bone vs beauty

The strongest silicon evidence is skeletal: trials show ch-OSA raises bone-collagen formation markers and supports density when combined with calcium and vitamin D. The beauty evidence is real but weaker — brittleness scores improve, but effect sizes are modest and heterogeneous. The mineral's marketing and its science point in slightly different directions.

3, 1

Frequently asked questions

Do I need a silicon supplement?

Most people get adequate silicon from grains and vegetables. Supplementation is a consideration for bone support in at-risk groups (postmenopausal women) rather than a universal need.1, 3

Is horsetail extract a good silicon source?

It supplies silicon, but as polymers with uncertain bioavailability, plus thiaminase concerns. ch-OSA is the evidence-backed choice.1, 3

Can silicon reverse hair loss?

No evidence for that. It improves hair strength and brittleness modestly in trials, but androgenetic hair loss is not a silicon deficiency.1, 3

The bottom line

Silicon biology is credible, while supplement evidence is formulation-specific and still limited. Hair-loss or universal bone-health claims go beyond the current research.

References

  1. Silicon and bone health: review and trials. International Journal of Endocrinology (2013) · other · PMID 23690531
  2. Effect of oral choline-stabilized orthosilicic acid on skin, nails and hair. Archives of Dermatological Research (2005) · randomized trial · PMID 15905924
  3. Orthosilicic acid compound summary. PubChem, National Library of Medicine (2026) · ingredient monograph · CID 14942
  4. Dietary Supplements. U.S. Food and Drug Administration (2025) · government guidance

Revision history

  1. Replaced search-result citations with exact sources, mapped claims to evidence, and reassessed evidence strength.