Moderate evidenceJoints & skin

Orthosilicic Acid (ch-OSA)

A bioavailable form of silicon with several small randomized trials on hair, nails, skin and bone markers. The effects are real but modest, and nearly all the trials come from the same manufacturer.

Evidence last reviewed: August 2026

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What the science says

Skin, hair and nails Moderate evidence
A randomized placebo-controlled trial in women with photodamaged skin found improvements in skin roughness and elasticity and in nail and hair brittleness over 20 weeks. A second randomized trial in women with fine hair reported increased hair tensile strength and changes in hair morphology after 9 months.
Bone formation markers Limited evidence
A randomized placebo-controlled trial in osteopenic women found that ch-OSA added to calcium and vitamin D stimulated markers of bone formation. The trial measured biochemical markers and partial bone density changes, not fractures.
Knee osteoarthritis Limited evidence
A 12-week randomized, double-blind, placebo-controlled multicentre trial in 166 patients found no effect of ch-OSA on the primary outcome, WOMAC pain, in the group overall. A benefit appeared only in the male subgroup, which is a post-hoc style finding that needs confirmation.

Dosage & safety

Studied doseStudied doses are 5–10 mg of silicon per day as choline-stabilized orthosilicic acid, taken for 20 weeks to 12 months. Effects on hair and nails take months to appear.

SafetyWell tolerated in trials lasting up to a year, with no significant adverse effects reported. Silicon is poorly absorbed and excreted by the kidneys, so people with significant kidney impairment should be cautious. Not studied in pregnancy or children.

Scientific references

Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin
Barel A, Calomme M, Timchenko A — Arch Dermatol Res, 2005
Effect of oral intake of choline-stabilized orthosilicic acid on hair tensile strength and morphology in women with fine hair
Wickett RR, Kossmann E, Barel A — Arch Dermatol Res, 2007
A 12-week randomized, double-blind, placebo-controlled multicenter study of choline-stabilized orthosilicic acid in patients with symptomatic knee osteoarthritis
Geusens P, Pavelka K, Rovensky J — BMC Musculoskelet Disord, 2017

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