Equisetum arvense, commonly known as horsetail, is an ancient plant with a rich history spanning millennia. Found across various continents, horsetail continues to draw interest for its distinctive characteristics and traditional uses.
What is Horsetail?
Horsetail is a perennial fern belonging to the genus Equisetaceae, characterized by its hollow, segmented stems that resemble a horse’s tail or a bottlebrush. These jointed stems typically grow one to two feet tall and are green, with small, scaly leaves. It thrives in damp, sandy soils and can be found wild in regions of northern Europe, North America, and Central America. It is considered a “living fossil” due to its ancient lineage.
Traditional and Modern Applications
Historically, horsetail has been employed in traditional medicine for various purposes. It was commonly used as a diuretic to increase urine excretion and as an astringent to help stop bleeding and promote wound healing. Traditional applications also included its use for kidney and bladder ailments, such as urethritis and cystitis with hematuria. Some historical uses also included its application as a cosmetic component.
Modern scientific interest in horsetail focuses on its active compounds, particularly silica and flavonoids, which are believed to contribute to its potential health effects. Silica, a compound of silicon and oxygen, is thought to support bone health, as well as strengthen hair and nails. Research includes studies where horsetail ointment applied topically promoted wound healing and pain relief. Its diuretic effects have also been investigated, with one study showing a daily dose of dried horsetail extract had a more potent diuretic effect than a classic diuretic drug. While these findings are promising, much of the modern research is preliminary and often conducted in animal models or small human studies, indicating a need for more extensive clinical trials to confirm these benefits.
How to Use Horsetail
Horsetail is available in several forms for consumption and topical application. It is commonly found as a dried herb, which can be steeped in hot water to prepare teas. Tinctures, capsules, and standardized extracts are also widely available, offering different concentrations of the plant’s active compounds. When preparing horsetail tea, approximately one to two teaspoons of the dried herb per cup of hot water is a common approach.
For standardized extracts, it is generally advised to follow the specific instructions provided on the product label, as concentrations can vary. When using topical preparations, application frequency and duration should align with product guidelines or professional advice.
Safety and Precautions
While Equisetum arvense is generally considered safe when used appropriately, important safety considerations and potential side effects exist. Long-term use of unprocessed horsetail may lead to thiamine (vitamin B1) deficiency because the plant contains thiaminase, an enzyme that breaks down thiamine. Some individuals may experience mild digestive upset.
Certain groups should avoid horsetail due to contraindications. Pregnant or breastfeeding individuals are advised against its use. Those with pre-existing kidney or heart conditions, or individuals already experiencing thiamine deficiency, should also exercise caution or avoid it entirely.
Horsetail can interact with various medications, including diuretics, potentially enhancing their effects, and lithium, which could lead to increased lithium levels in the body. It may also interact with medications like digoxin, phenytoin, and anticoagulants. Consulting a healthcare professional before using horsetail supplements is recommended, especially for those with underlying health conditions or who are taking other medications.