Horsetail (Silica): Uses, Benefits, Dosage & Safety
Last updated: June 2026 · Reviewed by the FactoWiki Editorial Team for clarity and source accuracy
Quick summary
Horsetail is a silica-rich plant used for hair, nails, skin and bone support, and as a mild diuretic. Silica's structural role is real, but human evidence for these benefits is limited, and there are safety cautions.
What is Horsetail?
Horsetail (Equisetum arvense) is an ancient plant high in silica (silicon), a mineral involved in collagen and connective tissue. It's marketed for hair, nail and skin strength, bone support, and as a traditional diuretic.
What Horsetail is commonly used for
In supplements, Horsetail is most often included for nail & foot care, skin & anti-aging support. It is used as nutritional support, not as a treatment for any medical condition — the distinction matters, because the claims on a sales page are often stronger than the evidence allows.
How Horsetail works
Silicon contributes to the formation of collagen and connective tissue, which is the rationale for horsetail's hair, nail, skin and bone marketing. Its diuretic effect comes from other plant compounds. Whether supplementing improves these tissues in well-nourished people is unproven.
What the evidence says
Here's an honest snapshot of what published research suggests about Horsetail — including where the evidence is limited.
- Silicon has a plausible structural role in collagen and bone, and a few small studies hint at nail or skin benefit, but evidence is limited. (PubMed research)
- Horsetail's diuretic use is traditional, with little rigorous human confirmation. (PubMed research)
Typical dosage used in studies
Used as tea, tincture or extract; standardised silica products vary in dose. This is research information for context, not a recommendation — confirm what's appropriate for you with a healthcare professional.
Side effects and safety
Caution is warranted: horsetail contains an enzyme (thiaminase) that can break down vitamin B1, so only thiaminase-free products should be used long term. Its diuretic effect can affect fluid and potassium balance.
Medication interactions and who should avoid Horsetail
Medication & safety check
As a diuretic it may interact with diuretic, lithium and heart medication, and deplete potassium and thiamine. Avoid in pregnancy and in people with kidney or heart conditions without advice.
This is general information, not personal medical advice. If you take any medication, confirm it's safe to combine with Horsetail with your doctor or pharmacist first.
Sources & further reading
The summary above is drawn from peer-reviewed research and authoritative references. For general, authoritative background you can also consult:
- PubMed research on Horsetail
- NIH Office of Dietary Supplements
- NIH National Center for Complementary and Integrative Health
- MedlinePlus (U.S. National Library of Medicine)
Frequently asked questions
Does horsetail strengthen hair and nails?
Its silica has a structural rationale, but human evidence for visible benefit is limited.
Is horsetail safe?
Use thiaminase-free products; raw horsetail can deplete vitamin B1, and it acts as a diuretic.
What is silica good for?
Silicon contributes to collagen and connective tissue, supporting skin, nails and bone.
Who should avoid horsetail?
People with kidney or heart conditions, on diuretics or lithium, and pregnant women.
Supplements that contain Horsetail
On FactoWiki, Horsetail appears in these reviewed products. Each review breaks down the full formula, pricing and safety.
- Synevra Ultralift — Skin & Anti-Aging
Related ingredients to explore
Ingredients often studied or formulated alongside Horsetail — useful for understanding the full picture of a formula.