Benefits
Supports Healthy Urinary Function
Horsetail has a long traditional use as a mild aquaretic (a herb that increases urine flow without a strong electrolyte-wasting effect). This use rests on traditional practice — no human diuretic trial of horsetail is cited on this page.
Contributes Bioavailable Silica
Silica is involved in the structural integrity of bone, cartilage, hair, skin, and nails. Horsetail provides a plant-based source of silicic acid that supplements the silicon naturally obtained from foods like whole grains and vegetables.
Supports Hair and Nail Strength
The combination of silica and flavonoids has made horsetail a popular component in beauty-from-within formulas aimed at supporting normal hair growth cycles, nail thickness, and skin firmness.
Promotes Bone Wellness
Silica plays a role in collagen cross-linking and bone matrix formation. Horsetail extracts have been explored for bone support alongside calcium and vitamin D, but the bone evidence cited here is entirely from animal studies.
Provides Antioxidant Flavonoids
Isoquercitrin and kaempferol glycosides in horsetail offer free-radical scavenging activity, supporting the body's defense against everyday oxidative stress.
Mechanism of action
Aquaretic Diuretic Action
Horsetail flavonoids and saponins increase urinary water excretion (an aquaretic effect) without major losses of sodium or potassium, distinguishing it from pharmaceutical loop diuretics.
Silica Bioavailability
Plant silica is converted into orthosilicic acid in the gut, which is then absorbed and incorporated into collagen, glycosaminoglycans, and bone matrix proteins.
Connective-Tissue Cross-Linking
Silicon is hypothesized to participate in cross-linking collagen and elastin fibers in skin, hair, cartilage, and bone, supporting structural strength and elasticity.
Antioxidant Flavonoid Activity
Isoquercitrin and kaempferol glycosides scavenge reactive oxygen species and modulate inflammatory signaling, providing cellular-defense support that complements the herb's mineral content.
Clinical trials
Preclinical model of age-related osteosarcopenia using standardized Equisetum arvense extract
Aged murine model with measurements of bone microstructure and muscle mass
In MICE, daily oral standardized horsetail extract was associated with preservation of bone microarchitecture and muscle parameters versus untreated controls. This is an animal study of age-related bone and muscle loss; it is mechanistic support only and has not been shown in people.
Animal study using digital radiography to measure bone mineral density
Wistar rats receiving Equisetum arvense extract
In WISTAR RATS (n=50, 30 days), mandibular bone mineral density was higher in the horsetail-treated group than controls. This is an animal study; no human bone-density trial of horsetail is cited on this page.