Wildcrafted Horsetail
Also known as: Horsetail, common horsetail, field horsetail, wildcrafted horsetail, Equisetum arvense
Overview
Equisetum arvense, commonly known as horsetail, field horsetail, or wildcrafted horsetail, is a perennial fern-like plant found in temperate regions. The term "wildcrafted" indicates that the plant is harvested from its natural habitat. Traditionally, it has been used in herbal medicine for various conditions, including urinary tract issues, wound healing, inflammation, and supporting bone health. Its key characteristics include a high silica content and various polyphenols. However, it also contains thiaminase, an enzyme that can degrade vitamin B1. While in vitro studies and some clinical trials exist, large-scale, high-quality randomized controlled trials (RCTs) or systematic reviews specifically on wildcrafted horsetail are limited, meaning the evidence quality is moderate and largely based on traditional use and preclinical data.
Benefits
In vitro studies suggest that *Equisetum arvense* possesses anti-inflammatory and antioxidant properties. A standardized extract has been shown to inhibit human T cell proliferation and reduce the production of inflammatory cytokines (IL-2, IFN-γ, TNF-α) in vitro, indicating potential immunomodulatory effects. This suggests it could be beneficial in managing inflammatory disorders, though clinical evidence is needed. Additionally, polyphenolic extracts have demonstrated the ability to protect red blood cells from oxidative damage in vitro, pointing to potential cytoprotective effects. Traditionally, horsetail has been used for wound healing, urinary tract conditions, and bone health, likely due to its silica content, but robust clinical evidence to support these specific traditional uses is sparse and not well-quantified. The strength of evidence for these benefits is primarily from in vitro studies, with limited human clinical data.
How it works
The anti-inflammatory effects of *Equisetum arvense* are believed to be mediated by its ability to inhibit lymphocyte activation and cytokine production, thereby reducing T cell proliferation and their effector functions. Its antioxidant activity is attributed to the polyphenolic compounds present, which scavenge free radicals and protect cellular components, such as red blood cells, from oxidative damage. The high silica content in horsetail is thought to contribute to its traditional use for connective tissue and bone health, potentially by providing structural components, although the direct clinical mechanism and absorption into these tissues are not fully elucidated. Data on the absorption and bioavailability of its active compounds in humans are limited, and research often utilizes standardized extracts to ensure consistent phytochemical profiles.
Side effects
While generally considered relatively safe for short-term use, horsetail carries several risks, particularly with prolonged consumption. Common side effects include potential thiamine (vitamin B1) deficiency due to the presence of the enzyme thiaminase, and anecdotal reports of gastrointestinal upset. Uncommon side effects include hypoglycemia, especially in diabetic patients when combined with glucose-lowering medications. Rare but serious side effects include hepatotoxicity, with isolated case reports linking horsetail ingestion to acute liver injury and jaundice. Horsetail may interact with various medications, including diabetes medications (potentiating hypoglycemic effects), diuretics (due to its own diuretic properties), and drugs metabolized by the liver. It is contraindicated in pregnancy, breastfeeding, individuals with thiamine deficiency, and those with pre-existing liver disease. Caution is advised for individuals with diabetes due to its potential to affect blood sugar levels.
Dosage
There is no standardized dosing for *Equisetum arvense* established through high-quality clinical trials. Traditional herbal preparations often suggest a range of 300 mg to 900 mg of extract daily, but the clinical efficacy and safety at these specific doses are not well-documented. Due to the presence of thiaminase and potential for toxicity, long-term use is generally discouraged. The timing of administration and the form of consumption (e.g., tea, extract, capsule) may influence absorption and efficacy, but these factors have not been rigorously studied. Given the safety concerns, particularly regarding thiamine depletion and rare hepatotoxicity, it is prudent to use the lowest effective dose for the shortest possible duration, and to consult a healthcare professional before use.
FAQs
Is wildcrafted horsetail safe?
It is generally safe for short-term use, but caution is advised due to the risk of thiamine deficiency and rare reports of liver toxicity, especially with prolonged use.
Can it cause vitamin B1 deficiency?
Yes, prolonged or excessive use of horsetail can lead to thiamine (vitamin B1) depletion due to the presence of the enzyme thiaminase.
Does it lower blood sugar?
Horsetail may lower blood sugar levels and can cause hypoglycemia, particularly when combined with diabetes medications.
How quickly do benefits appear?
There is no robust clinical data on the onset of benefits. While anti-inflammatory effects have been shown in vitro, the timeline for clinical effects in humans is unknown.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC4132922/ – This in vitro study investigated the immunomodulatory effects of *Equisetum arvense* extract on human lymphocytes. It found that the extract dose-dependently inhibited T cell proliferation and reduced the production of inflammatory cytokines (IL-2, IFN-γ, TNF-α), suggesting potential anti-inflammatory properties. The study highlights the need for further in vivo and clinical investigations.
- https://www.ncbi.nlm.nih.gov/books/NBK583202/ – This entry from LiverTox (NCBI Bookshelf) details a case report of acute hepatocellular jaundice linked to horsetail ingestion. The patient experienced elevated liver enzymes which improved after discontinuing horsetail. This report serves as a safety signal for potential hepatotoxicity, although it is a single case and does not establish causality definitively.
- https://www.thailandmedical.news/news/polish-study-finds-that-field-horsetail-plant-extract-shields-red-blood-cells-from-damage-and-stress – This summary refers to a Polish in vitro study demonstrating that polyphenolic extracts of field horsetail can protect red blood cells from oxidative damage. The findings suggest potential antioxidant and cytoprotective effects, indicating that horsetail may help mitigate cellular stress, though these results are from a preclinical setting.