Horsetail Extract (leaf and stem)
Also known as: Equisetum arvense, common horsetail, Horsetail, field horsetail, shavegrass, Equisetum hyemale, scouring rush
Overview
Horsetail extract is derived from the aerial parts (leaf and stem) of the plant *Equisetum arvense*, a perennial fern-like plant traditionally used in herbal medicine. It is rich in minerals such as silica, flavonoids, alkaloids, phenols, and tannins. Horsetail has been traditionally used for urinary tract conditions, wound healing, and bone health support. Modern research investigates its antioxidant, anti-inflammatory, antimicrobial, and potential bone-regenerative properties. The evidence base is moderate, with some preclinical and limited clinical studies, but few large-scale randomized controlled trials (RCTs) or systematic reviews specifically on horsetail extract as a supplement. It is available in various forms, including capsules, powders, and liquid extracts.
Benefits
- **Bone Health:** Horsetail contains bioavailable silicon, a mineral important for bone formation and density. Animal studies have shown increased bone density with horsetail extract supplementation (e.g., rats given 120 mg/kg showed improved bone density). This supports its traditional use for osteoporosis, though human clinical evidence remains limited. - **Antioxidant and Anti-inflammatory Effects:** Horsetail extract exhibits antioxidant activity due to flavonoids and phenolic compounds, which may contribute to anti-inflammatory effects observed in vitro and in animal models. - **Hair Growth:** A flavonoid-rich extract of *Equisetum hyemale* (a related species) demonstrated hair regenerative activity in a rat model over 28 days, indicating potential for stimulating hair growth, though human data are lacking. - **Antimicrobial and Other Effects:** Horsetail shows antibacterial, antifungal, antidiabetic, anticonvulsant, and antitumor activities in preclinical studies, but these are not yet confirmed in clinical trials.
How it works
The mechanisms of action of horsetail extract are attributed to its various bioactive compounds. Silicon in horsetail is believed to enhance collagen synthesis and bone mineralization, supporting connective tissue and bone strength. Flavonoids and phenolics contribute to antioxidant activity by scavenging free radicals and reducing oxidative stress. Anti-inflammatory effects are likely mediated through modulation of inflammatory cytokines and enzymes, though specific molecular targets require further elucidation. Silicon from horsetail is bioavailable in forms such as orthosilicic acid, but absorption rates and bioavailability in humans need more study.
Side effects
Horsetail is generally considered safe when used short-term at typical doses. However, it contains thiaminase, which can degrade vitamin B1 (thiamine), potentially leading to deficiency with prolonged use. Common side effects include mild gastrointestinal discomfort. Uncommon or rare side effects include potential allergic reactions or interactions with diuretics and lithium. It may interact with diuretics, lithium, and drugs metabolized by the liver. Horsetail is contraindicated in pregnancy, breastfeeding, and in individuals with thiamine deficiency or kidney disease. Caution is advised in special populations due to limited safety data. Vitamin B1 supplementation may be advisable during prolonged use to mitigate thiamine depletion.
Dosage
Typical doses used in animal studies were 120 mg/kg. Human doses in supplements vary widely, often around 300-600 mg/day of extract standardized to flavonoids or silica content. Extracts standardized for flavonoid or silica content are preferred. There is no specific timing established; it is usually taken orally with meals. The maximum safe dose is not well defined; prolonged high doses are discouraged due to thiaminase content. Vitamin B1 supplementation may be advisable during prolonged use. Consult with a healthcare professional for personalized dosage recommendations.
FAQs
Is horsetail effective for osteoporosis?
Animal studies suggest a potential benefit, but robust human clinical trials are lacking to confirm its effectiveness for osteoporosis.
Can horsetail promote hair growth?
Preliminary animal data are promising, but human evidence is insufficient to support the claim that horsetail promotes hair growth.
Is horsetail safe long-term?
Prolonged use may risk vitamin B1 deficiency due to thiaminase content; short-term use appears safer. Consider B1 supplementation with long-term use.
Does horsetail interact with medications?
Yes, especially diuretics and lithium. Consult healthcare providers before using horsetail if you are taking any medications.
Research Sources
- https://www.ncbi.nlm.nih.gov/books/NBK583202/ – This LiverTox review provides a comprehensive overview of horsetail’s traditional uses and safety profile. It highlights the potential for thiamine depletion with long-term use and advises caution. The review does not cite any large randomized controlled trials (RCTs) regarding horsetail supplementation.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7321494/ – This PMC article reviews horsetail’s chemical composition and pharmacological activities, including its antioxidant, anti-inflammatory, and antimicrobial effects. The data presented are primarily preclinical, with no human RCTs reported. The review emphasizes the need for further clinical studies to validate these findings in humans.
- https://jppres.com/jppres/pdf/vol7/jppres19.557_7.5.323.pdf – This study investigated the effects of a flavonoid-rich *Equisetum hyemale* extract on hair growth in rats. The results showed statistically significant hair growth over 28 days (p<0.05), with histopathological evidence of hair follicle development. While the sample size and control groups were adequate for an animal study, there are no corresponding human data available.
- https://www.signos.com/blog/horsetail-herb – This blog post discusses the benefits of horsetail herb, including its potential to increase bone density. It cites animal studies where rats administered 120 mg/kg of horsetail extract showed increased bone density compared to controls, supporting silicon’s role in bone health. The post notes the absence of human RCTs on this topic.
- https://www.mountsinai.org/health-library/herb/horsetail – This Mount Sinai Health Library entry provides an overview of horsetail, including its traditional uses and potential health benefits. It mentions the herb's use in treating urinary tract conditions and supporting bone health. The entry emphasizes the need for more research to confirm these benefits and establish safe usage guidelines.