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Hrs2.5

Horsetail Research

Mostly mechanism / observationalLimited safety

4 peer-reviewed studies

What the evidence says

Mostly mechanism / observational

Most Horsetail studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.

Most evidence is from medium-quality randomised trials published 2011–2015 with a typical study size of 36 participants.

Based on 4 studies · 2 RCTs · 145 total participants

Confidence

Low

By outcome

Safety profile
Too few graded studies1 study

Older research base

Newest study from 2015

20112015

1Crossovern=36 · small study2014

A standardized horsetail extract produced a diuretic effect equivalent to hydrochlorothiazide without significant electrolyte loss.

Carneiro DM, Freire RC, Honório TC, et al. · Evid Based Complement Alternat Med (2014)

36 healthy men in a crossover design comparing horsetail extract (900 mg/day), placebo, and hydrochlorothiazide
Horsetail's diuretic effect was stronger than placebo and comparable to hydrochlorothiazide
No significant change in electrolyte elimination; rare minor adverse events

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2RCTn=108 · medium study2015

A 3% horsetail ointment promoted episiotomy wound healing and reduced pain over a 10-day period versus placebo.

Asgharikhatooni A, Bani S, Hasanpoor S, Mohammad Alizade S, Javadzadeh Y · Iran Red Crescent Med J (2015)

108 postpartum women randomized to topical 3% horsetail ointment or placebo
Lower wound-healing (REEDA) and pain (VAS) scores in the horsetail group
Acetaminophen use was actually higher in the horsetail group (not reduced)

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3In Vitro2012

A hydromethanolic horsetail extract dose-dependently inhibited human osteoclast formation in cell culture.

Costa-Rodrigues J, Carmo SC, Silva JC, Fernandes MH · Cell Prolif (2012)

In-vitro study of horsetail extract on human osteoclast precursors
Dose-dependent inhibition of osteoclastogenesis at concentrations ≥0.004 mg/ml
Suggests a theoretical bone-protective mechanism only

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4Case Studyn=1 · very small study2011

Horsetail's thiaminase activity, combined with diet and alcohol, was proposed to potentiate a thiamine deficiency during pregnancy.

Ortega García JA, Angulo MG, Sobrino-Najul EJ, et al. · J Med Case Rep (2011)

Case report flagging horsetail's thiaminase content as a thiamine-depletion hazard
Mother used ~1200 mg/day horsetail and reported B-complex deficiency during pregnancy
Authors recommend avoiding such herbal supplements in pregnancy

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View in Research Library

Horsetail Research

Mostly mechanism / observational

Randomized, Double-Blind Clinical Trial to Assess the Acute Diuretic Effect of Equisetum arvense (Field Horsetail) in Healthy Volunteers.

The effect of equisetum arvense (horse tail) ointment on wound healing and pain intensity after episiotomy: a randomized placebo-controlled trial.

Inhibition of human in vitro osteoclastogenesis by Equisetum arvense.

Prenatal exposure of a girl with autism spectrum disorder to 'horsetail' (Equisetum arvense) herbal remedy and alcohol: a case report.