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.
In short
Silicon is a trace mineral that concentrates in connective tissue, where it cross-links collagen and elastin and supports bone mineralization. In the body it exists as orthosilicic acid — the bioavailable form found in mineral water, whole grains, and vegetables, and supplied by supplements (often as choline-stabilized orthosilicic acid, or ch-OSA). The evidence is strongest for bone: several trials show improved bone density markers and collagen formation, particularly in osteopenic women, and epidemiologic data link higher silicon intake with denser bones. Hair, skin, and nail trials show modest improvements in brittleness and texture, though the data are smaller and more mixed. Dietary adequacy varies widely — average intakes (20–50 mg/day) meet needs, and deficiency outside specific contexts is essentially unknown.
- Trace mineral concentrated in bone and connective tissue
- Bioavailable form: orthosilicic acid (ch-OSA in supplements)
- Best evidence: bone collagen and density markers
- Hair/skin/nail trials modest; deficiency essentially unknown
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.
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
Benefits
Bone density and collagen markers
moderate evidenceTrials of ch-OSA in osteopenic women report increased bone-collagen markers (P1NP) and, in some studies, improved femoral bone density.
Skin elasticity
emerging evidenceSmall trials report improved skin roughness and brittleness scores with ch-OSA supplementation.
Hair and nail strength
emerging evidenceTrials show reduced nail brittleness and improved hair tensile strength; effects are modest and the data are limited.
Side effects & safety
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)
How it's used
In supplements
5–10 mg elemental silicon/day as ch-OSA is typical; horsetail extracts supply variable amounts.
In skincare
Silica appears in makeup and texture agents; not an active.
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.
Popular products containing Silicon
- BioSil (ch-OSA) — Choline-stabilized orthosilicic acidBioSil · Supplement
- NOW Silica Complex — Horsetail-derived silicaNOW Foods · Supplement
- Swanson Bamboo Silica — Plant-source silica capsulesSwanson · Supplement
Product names and brands are shown for reference and belong to their respective owners.
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.
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.
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.
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.
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.
The bottom line
Silicon is a genuine connective-tissue mineral with its best evidence in bone support — while the hair-skin-nails marketing runs ahead of a modest, though not empty, cosmetic evidence base.
References
- Silicon and bone health: review and trials. PubMed Central. https://pubmed.ncbi.nlm.nih.gov/23690531/
- Choline-stabilized orthosilicic acid and skin/nails/hair. PubMed. https://pubmed.ncbi.nlm.nih.gov/15905924/
- Silicon — Linus Pauling Institute. Oregon State University. https://lpi.oregonstate.edu/mic/minerals/silicon