Prêle commune Equisetum

Horsetail works primarily through its exceptionally high silica (silicon) content, which supports collagen formation and connective tissue strength. The herb contains flavonoids like kaempferol and quercetin that provide anti-inflammatory and diuretic effects by increasing urine output. Its astringent compounds, including equisetonin, contribute to wound healing and hemostatic properties by helping to stop bleeding. Evidence level: C and Traditional use supports these mechanisms, though clinical trials remain limited.

Yes, horsetail can interact with several medications. Due to its diuretic effects, it may increase the elimination of lithium, potentially reducing its effectiveness and requiring dosage adjustments. Horsetail should not be combined with other diuretic medications as this may cause excessive fluid loss and electrolyte imbalances. The herb may also interact with antidiabetic medications by affecting blood sugar levels. Patients taking these medications should consult a healthcare provider before using horsetail supplements. Evidence level: C.

The typical adult dosage for horsetail is 6 grams of dried herb prepared as a tea, taken daily. Alternatively, standardized extracts of 300-600mg daily are commonly used. Horsetail should not be used for extended periods without medical supervision due to the risk of thiamine deficiency from prolonged consumption. Dosage may vary based on the specific preparation and condition being addressed. Evidence level: C and Traditional use.

No, horsetail is considered unsafe during pregnancy and breastfeeding and should be avoided. The herb contains trace amounts of nicotine and has potent diuretic effects that may disrupt fluid and electrolyte balance during pregnancy. Additionally, prolonged use can deplete thiamine (vitamin B1), which is essential for fetal development. There is insufficient safety data for breastfeeding. Pregnant and nursing women should not use horsetail supplements. Evidence level: C.

Yes, prolonged use of horsetail can cause thiamine (vitamin B1) deficiency. Horsetail contains a thiaminase enzyme that breaks down thiamine in the body, potentially leading to deficiency symptoms including fatigue, confusion, nerve problems, and muscle weakness. This risk increases with long-term consumption. Horsetail is contraindicated in people with existing thiamine deficiency or those at risk. Use should be limited to short periods unless supervised by a qualified healthcare professional. Evidence level: C.

Horsetail has been traditionally used to support bone and connective tissue health due to its exceptionally high silica content, which plays a role in collagen synthesis and bone mineralization. Some preliminary research suggests potential benefits for bone density, but clinical evidence remains limited. The herb should not replace conventional osteoporosis treatments or calcium and vitamin D supplementation. Evidence level: C and Traditional use. Patients with bone conditions should consult a healthcare provider.