Horsetail (Equisetum arvense) is an ancient herbal remedy recognized for its various health-enhancing properties. Traditionally, it has been valued for its potential to promote the health of hair, skin, and nails, although scientific validation for these claims remains limited. This remarkable fern has a rich history, having been utilized as a natural remedy dating back to the Greek and Roman Empires. Horsetail is thought to possess numerous medicinal attributes and has been traditionally employed for treating wounds, improving skin, hair, and bone health, and addressing a range of other health issues. However, it is crucial to note that there is insufficient human evidence to substantiate many of these traditional applications.

This article delves into the world of horsetail, examining its potential benefits, various uses, and potential drawbacks, shedding light on both its historical significance and current relevance.

Understanding Horsetail

Field or common horsetail (Equisetum arvense), a perennial fern belonging to the genus Equisetaceae, is a fascinating plant. This resilient species thrives in the wild across northern Europe, as well as in North and Central America, predominantly in moist environments characterized by temperate climates. Its long, green, and densely branched stem flourishes from spring through fall, creating a striking appearance in its natural habitat.

Horsetail is rich in numerous beneficial compounds that contribute to its health-promoting properties. Among these, antioxidants and silica are particularly noteworthy. Antioxidants are vital molecules that help safeguard the body against the harmful effects of free radicals, which can lead to cellular damage. On the other hand, silica, a compound composed of silicon and oxygen, is thought to underpin horsetail’s potential benefits for the skin, nails, hair, and bones, making it a valuable addition to one's diet.

This remarkable plant is primarily enjoyed as a tea, which is prepared by steeping dried horsetail herb in hot water. Additionally, it is available in various forms, including capsules and tinctures, making it accessible for those looking to incorporate its benefits into their wellness routine.

The Potential Benefits of Horsetail

For centuries, horsetail has been utilized as an herbal remedy, and while scientific evidence remains limited, its potential health benefits continue to attract interest.

Enhances Bone Health

Research indicates that horsetail may play a role in promoting bone healing processes. The dynamic nature of bone metabolism involves bone cells known as osteoblasts and osteoclasts, which constantly remodel bone structure to prevent imbalances that might lead to brittleness. Osteoblasts are responsible for bone formation, while osteoclasts are tasked with bone resorption.

In vitro studies suggest that horsetail could inhibit osteoclast activity while stimulating osteoblast function, highlighting its potential utility for conditions like osteoporosis, where overactive osteoclasts lead to fragile bones. A notable study involving rats demonstrated that a daily intake of 55 mg of horsetail extract per pound (approximately 120 mg per kg) of body weight significantly boosted bone density compared to a control group.

Researchers attribute horsetail's positive bone remodeling effects primarily to its remarkable silica content, which constitutes nearly 25% of its dry weight. This high concentration of silica is unmatched among plants. Silica enhances the formation, density, and integrity of bone and cartilage by promoting collagen synthesis and optimizing calcium absorption and utilization.

Functions as a Natural Diuretic

Diuretics are substances that promote increased urine production, and the diuretic properties of horsetail are among its most valued attributes in traditional medicine. One small-scale study involving 36 healthy males indicated that a daily dosage of 900 mg of dried horsetail extract in capsule form exhibited a more pronounced diuretic effect than conventional diuretic medications. This efficacy was attributed to the plant's high levels of antioxidants and mineral salts.

Horsetail has also shown promise as a natural treatment for urinary incontinence, urgency, and nocturia—characterized by nighttime urination. A 2021 review highlighted the potential of horsetail in addressing kidney-related issues, including urethritis and kidney stones, though it’s essential to note that human research is still limited.

Facilitates Wound Healing and Supports Nail Health

Topical application of horsetail ointment appears to aid in wound healing. In a 10-day study involving 108 postpartum women who underwent episiotomy during childbirth, the use of an ointment containing 3% horsetail extract significantly improved wound healing and reduced pain. The study also noted substantial improvements in wound redness, swelling, and discharge when compared to a control group, effects attributed to horsetail's silica content.

Older studies in rats demonstrated that ointments with 5% and 10% horsetail extract achieved wound closure rates of 95–99% and enhanced skin regeneration relative to control groups. Furthermore, horsetail extract is being explored for use in nail polish to help manage nail psoriasis, a condition that leads to nail deformities. Research found that a nail lacquer combining horsetail extract and other strengthening agents reduced symptoms of nail psoriasis. However, more studies are necessary to confirm these claims.

Encourages Hair Growth

Emerging research suggests that horsetail may also contribute to hair health, likely due to its silicon and antioxidant properties. Antioxidants work to mitigate micro-inflammation and prevent the aging of hair fibers caused by free radicals. Additionally, higher levels of silicon in hair fibers correlate with reduced hair loss and increased shine.

For instance, a 3-month study involving women experiencing perceived hair thinning showed that those who took two daily capsules containing dried horsetail and other ingredients experienced improved hair growth and strength compared to a control group. Other studies exploring various mixtures containing horsetail-derived silica have yielded similar findings. However, research focusing solely on horsetail's effects remains limited.

Other Potential Advantages

Horsetail is recognized for its myriad potential benefits, including:

• Anti-inflammatory properties. In vitro studies suggest that horsetail extract may inhibit lymphocytes, which are key defense cells involved in inflammatory conditions.
• Antimicrobial properties. Horsetail essential oil exhibits significant activity against a range of bacteria and fungi, including Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Candida albicans.
• Antioxidant properties. Research indicates that horsetail is rich in phenolic compounds, potent antioxidants that help prevent oxidative damage to cellular membranes.
• Antidiabetic effects. Findings from animal and in vitro studies suggest that horsetail extract may aid in lowering blood sugar levels and regenerating damaged pancreatic tissue.

Applications and Dosage Recommendations

Horsetail, also known as Equisetum arvense, is predominantly promoted as a remedy for enhancing the health of skin, hair, and nails. Additionally, there are formulations that claim to aid in managing urinary and kidney-related issues. In terms of dosage, a human study indicated that the consumption of 900 mg of horsetail extract capsules—this aligns with the maximum recommended daily intake for dry extracts as outlined by the European Medicines Agency—over a duration of four days could potentially elicit a diuretic effect. Despite this finding, it is important to note that a definitive appropriate dose has not yet been established through current scientific research.

Side Effects and Precautions

As with many herbal supplements, horsetail (shatavari) has not received approval from the Food and Drug Administration (FDA), making it essential for individuals who are pregnant or breastfeeding to refrain from its use. While studies conducted on rats indicate that horsetail is not toxic, further research involving human participants is crucial to establish its safety.

There is a potential for drug-herb interactions when horsetail is consumed alongside antiretroviral medications prescribed for the treatment of HIV, which warrants caution. For individuals suffering from kidney disease, the consumption of horsetail could elevate potassium levels to potentially hazardous heights. Consequently, it is generally advised that those with kidney issues avoid horsetail and other herbal supplements.

Moreover, horsetail contains nicotine, so it is advisable to avoid this herb if you have a nicotine allergy or are attempting to quit smoking. In a notable case, a 56-year-old woman developed pancreatitis due to drinking horsetail tea; her symptoms resolved once she discontinued its consumption.

Furthermore, horsetail exhibits thiaminase activity, an enzyme responsible for breaking down thiamine, or vitamin B1. Therefore, prolonged use of horsetail, or its intake by individuals with low thiamine levels—such as those with alcohol use disorder—could contribute to a deficiency in vitamin B1.

The Conclusion

Horsetail, known as Equisetum arvense, has been utilized as a traditional herbal treatment for many centuries across various cultures. This versatile herb is primarily valued for its potential benefits in addressing skin, hair, nails, and urinary issues. It can be ingested in various forms, including herbal tea, capsules, and tinctures, making it accessible for many users. Nevertheless, it's important to note that horsetail is not approved by the FDA. Caution is advised for pregnant and breastfeeding individuals, those with low levels of vitamin B1 (thiamine), and anyone currently on antiretroviral medications, as they should avoid its use.