Horsetail Extract (Silica)

Botanicalsilica sourceLimited dose evidence

Also known as: Equisetum arvense, horsetail herb extract, shavegrass, horsetail 7% silica

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An extract of the aerial parts of field horsetail, a plant that accumulates silica in its cell walls and has a long traditional use for hair, nails, and connective tissue. Extracts are usually standardized to about 7% silica, far lower than bamboo, and also contain flavonoids and small amounts of other minerals. Human trials of horsetail itself are sparse; the silicon-and-bone literature reviewed by Jugdaohsingh provides the general rationale.

Research summary

Provides silicon, thought to support collagen cross-linking and bone matrix formation, plus flavonoids; the plant's mild diuretic reputation is traditional rather than well studied.

Dosage

Daily amounts, of extract.

Lowest studiedTypical rangeHighest studiedUpper limit
200–500 mg

Doses are milligrams of horsetail extract, not elemental silicon. At 7% silica, 300 mg of extract provides about 21 mg silica, roughly 10 mg silicon. No RDA or UL exists for silicon. Trial evidence specific to horsetail was not located; ranges reflect typical product servings. Raw horsetail contains thiaminase, so heat-processed or extracted material is standard; products intended for long-term use often add thiamin. Not commonly used in pregnancy formulas.

Standardization: ≥ 7% silica (SiO2); some grades 10%

Source material: dried aerial parts of Equisetum arvense, extracted

As supplied: Typically 7% SiO2; 300 mg extract ≈ 21 mg silica

Forms of Silica

FormTypical doseElement %FormatsPrice
Horsetail Extract (Silica)200–500 mgCapsule, Powder, Tabletlow
Bamboo Extract (Silica)100–500 mgCapsule, Powder, Tabletmid

Format suitability

  • Capsule
  • Powder
  • Tablet
  • Softgel
  • Gummy
  • Liquid

Green-brown, grassy powder; capsules and tablets only. Modest dose fits one size-0 capsule.

Formulation notes

Contains thiaminase unless processed; pair with thiamin in long-term products. Horsetail is traditionally regarded as a mild diuretic, which is worth noting when it is combined with potassium-lowering drugs or other diuretics. Equisetum palustre (marsh horsetail) is a toxic look-alike; specify E. arvense on the spec.

  • Not for pregnancy

Sources

  1. Silicon and bone health (Jugdaohsingh 2007)PubMed

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