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Horsetail, also called equisetum arvenseis, is a plant that is part of the equisetopsida family. It was native to the Arctic but is now grown in different parts of Europe, North America, and Canada.

It has been medicinally used since ancient Greece predominantly as a diuretic, but also for skin and nail care, wound healing, osteoporosis, and bone repair.

Horsetail products are typically made using the leaves and stems of the plant, with the majority of products being either liquid or dried extracts that can be used in teas or supplement capsules.

The main nutritional components of horsetail are flavonoids, saponins, caffeic acid, phenolic compounds, alkaloids, sterols, and minerals.

Horsetail Extract Health Benefits

May Have a Diuretic Effect

Horsetail is commonly used to treat an overactive bladder, which leads to issues such as urinary leaks, bladder stones, and urinary tract infections.

Researchers have proposed that the silica mineral within horsetail may be able to help increase calcium stores that is needed for bone metabolism.

A limited amount of evidence has shown a slight diuretic effect as assessed by measures of fluid balance that is similar to a diuretic medication called hydrochlorothiazide [1].

Despite the lack of evidence, health commissions in countries like Germany have approved the use of horsetail as a diuretic for bacterial and inflammatory diseases of the urinary tract [2].

Horsetail may be a good alternative to prescription diuretics, but future studies are required to elucidate its mechanism of action and efficacy.

May Be an Antioxidant

Some experimental research suggest that certain extracts of horsetail possess high radical scavenging activity towards superoxide anion and hydroxyl radicals [3].

Other studies have also shown the antioxidant effects of horsetail extracts are protective against lipid peroxidation – oxidative degradation of fat that damages cells [4].

Lab studies have not yet been conducted to isolate the specific plant extracts that seem to be having such an effect on antioxidant activity.

Based on the composition of horsetail, the flavonoids and phenolic acids are recorded as the main compounds that are likely the bioactive constituents [5].

May Have Anti-Inflammatory Properties

Several of the numerous known components of horsetail extract have been reported to possess anti-inflammatory properties [6].

This has led to a slight immunosuppressant (suppressing the immune response) effect in research on human cancer cell lines [7].

Data has also indicated a dose-dependent inhibition of pro-inflammatory molecule proliferation such as IL-2 cytokine production. It might also cause a slight reduction in IFN-γ- and TNF-α-production, which could interfere with immune cell functionality and lower the proliferation of immunocompetent cells [8].

However, further studies are required to full prove its effectiveness.

How To Take Horsetail Extract?

Due to the lack of research on horsetail extract, there is no general recommended dose, and it is hard to make a sensible recommendation based on the limited research available.

If you are going to use horsetail extract, it is advised to stick to the recommended dose on the label and to consult your doctor before use.

Horsetail Extract Safety And Side Effects

Despite its extended use in many cultures, there are a clear lack of clinical studies to assess the safety of horsetail, especially its impact on renal function. This stance is supported by European Medicines Agencies, who conclude that “reliable data on the absorption, distribution, and pharmacokinetics of horsetail are scarce or completely lacking” [9].

One study found that its effect on liver, kidney, and blood function were mild and not a significant concern [10]. However, more evidence at a range of doses and in different forms is needed to fully analyze its safety.

Potential safety issues with horsetail extract are:

  • As horsetail could be a diuretic it may increase the excretion of essential nutrients such as potassium.
  • It contains an enzyme that inhibits the activity of vitamin B1.
  • Rare reports of nausea, excessive urination, and muscle weakness.

To add, as is the case for all herbal supplements, horsetail is not regulated or approved by the United States Food and Drug Administration. Therefore, people need to be careful when purchasing herbal supplements like horsetail as they may contain contaminants that are not listed on the label.


Horsetail extracts are made using the leaves and stems of the horsetail plant, being processed in a way to produce liquid or dried extracts.

Horsetail extract is a potential antioxidant and anti-inflammatory, and may be helpful as a diuretic agent to treat urinary leaks, bladder stones, and urinary tract infections.

This supplement has not yet been listed as safe to consume, and there is currently no reliable recommended dosage.

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Fact Checked

This article has been reviewed and fact-checked by a certified nutritionist, and only uses information from credible academic sources.