Horsetail extract is derived from the Equisetum arvense plant, a fern-like perennial found in various temperate regions across the Northern Hemisphere. The name “horsetail” comes from its mature appearance, which resembles a horse’s tail. Its uses date back to ancient Sumerian, Greek, and Roman times.
Key Compounds and Their Actions
Horsetail extract’s actions are attributed to compounds like silica, flavonoids, phenolic acids, and various minerals. Silica is particularly abundant, making up to 25% of the plant’s dry weight. This high silica content supports connective tissues, enhancing collagen synthesis and improving calcium absorption for bone and cartilage.
Flavonoids and phenolic acids are known for their antioxidant properties, protecting cells from oxidative stress and contributing to anti-inflammatory effects. Minerals such as potassium, manganese, and magnesium also support general bodily functions.
Common Traditional and Modern Applications
Horsetail extract is traditionally used for various purposes, with modern research exploring these applications. Its high silica content supports the health of hair, skin, and nails. Antioxidants in horsetail may help reduce micro-inflammation and aging of hair fibers, while a higher silicon content in hair is linked to reduced hair loss and increased brightness. In skincare, silica’s role in collagen production contributes to skin strength and elasticity, and the extract’s mild astringent action can help manage oily skin.
The extract’s role in bone health is also due to its silica content. Silica is a mineral needed for bone health, and studies have shown that horsetail extract can improve bone density. This effect stems from silica’s ability to enhance collagen synthesis and improve calcium absorption, both important for healthy bone tissue.
Horsetail has also been historically used as a diuretic, promoting increased urine output. A study indicated that a daily dose of 900 mg of dried horsetail extract had a diuretic effect comparable to a conventional diuretic drug. Additionally, traditional uses include wound healing and addressing certain kidney and bladder conditions, though more human studies are needed.
Important Considerations for Safe Use
While generally considered safe, horsetail extract has potential considerations. It contains thiaminase, an enzyme that can break down thiamine (vitamin B1). Prolonged or excessive use, particularly in individuals with pre-existing low thiamine levels, could potentially lead to a vitamin B1 deficiency. Individuals with alcohol use disorder, for example, should avoid horsetail products due to their increased risk of thiamine deficiency.
Horsetail can also act as a diuretic, which may lead to increased potassium elimination from the body. This can result in low potassium levels, making it unsuitable for individuals at risk of potassium deficiency or those with heart arrhythmias. People with kidney disease should avoid horsetail, as it could elevate potassium levels to unsafe concentrations.
The plant also contains nicotine, so individuals with a nicotine allergy or those attempting to quit smoking should avoid its use. Pregnant and breastfeeding individuals should also avoid horsetail due to a lack of sufficient safety data. Additionally, horsetail may interact with certain medications, including diuretics, lithium, and some antiretroviral drugs. It has also been reported to potentially cause a drop in blood sugar levels in individuals with diabetes.
Horsetail extract is available in various forms, including capsules, teas, and tinctures. A typical daily dose for a dry extract, according to the European Medicines Agency, may be around 900 mg, although an appropriate dose has not been definitively established by scientific evidence. It is always advisable to follow product label instructions and consult a healthcare professional before beginning any new supplement, especially if you have existing health conditions or are taking other medications. It is important to note that Equisetum palustre, a different species of horsetail, is toxic and should not be consumed by humans.