Horsetail
Horsetail suppliers and sourcing guide
Horsetail is the sterile green aerial stem of Equisetum arvense, a fern relative with jointed, silica-rich stems that grows in damp ground across the Northern Hemisphere and is mostly wild collected. The stems are dried and sold cut for tea, milled to powder, or extracted with water or water-alcohol. Extracts are often sold by silica (silicon dioxide) content.
- Category
- Botanicals and mushrooms
- Also known as
- Equisetum arvense · field horsetail · shavegrass · horsetail herb
- Facts checked
- November 2026
Forms and grades of horsetail
Suppliers sell different products under the same name. Specify the one you need.
Cut and sifted herb
Dried aerial stems in tea cut for infusions and further extraction.
Powder
Dried herb milled to a powder for capsules and tablets.
Silica-standardized extract
Extract with a declared silica or silicon content, measured gravimetrically or by ICP-OES.
Organic
Herb from certified organic or certified wild collection.
What to check on the COA
Compare each result with your own specification when the lot arrives.
- Identity
- Microscopy and HPTLC to confirm Equisetum arvense and exclude marsh horsetail (Equisetum palustre), which contains the alkaloid palustrine and is a known contaminant of wild collections.
- Silica assay
- Silica or silicon by gravimetric ash method or ICP-OES; the COA should state whether the result is silica or elemental silicon.
- Heavy metals
- Lead, arsenic, cadmium and mercury by ICP-MS against the buyer's limits and any Prop 65 exposure targets.
- Microbiology
- Total plate count, yeast and mold, E. coli and Salmonella. Raw cut herb and powder carry more microbial load than extracts and may be steam treated.
- Pesticide residues
- Multi-residue screen by GC-MS/MS and LC-MS/MS, required for organic claims and commonly asked for on conventional lots.
- Physical tests
- Loss on drying, particle size or mesh, and for extracts the extract ratio, carrier and residual solvents (USP <467> or the buyer's spec).
Storage, lots and expiry
Storage and shelf life
Keep cut herb, powder and extract sealed in lined bags or drums, cool, dry and out of direct light. Powders and dry extracts pick up moisture and cake once opened, so reseal containers and limit time open on the production floor. Shelf life or a retest date comes from the supplier's specification, and the marker assay is usually repeated at retest.
Lots and expiry dates
Silica content and the risk of mixed Equisetum species vary with collection site, so each lot needs its own identity test and assay. Record collection area and supplier lot, and keep an authenticated retain sample.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
The EU Novel Food status Catalogue entry for Equisetum arvense (POL-NF-00336) concerns only the aerial parts and lists them as not novel in food.
Source: ec.europa.eu (opens in a new tab)That entry notes that use of the aerial parts is known in food supplements and as an ingredient in tea.
Source: ec.europa.eu (opens in a new tab)
This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
Horsetail suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking horsetail suppliers now
Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.
Sell horsetail? Request a listingFrequently asked questions
What forms of horsetail can brands buy?
Common forms include cut and sifted herb, powder, silica-standardized extract and organic. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for horsetail include?
Expect identity, silica assay, heavy metals, microbiology, pesticide residues and physical tests, each with its method, specification and result for that lot.
How should horsetail be stored?
Keep cut herb, powder and extract sealed in lined bags or drums, cool, dry and out of direct light. Powders and dry extracts pick up moisture and cake once opened, so reseal containers and limit time open on the production floor. Shelf life or a retest date comes from the supplier's specification, and the marker assay is usually repeated at retest.
What is the regulatory status of horsetail?
The EU Novel Food status Catalogue entry for Equisetum arvense (POL-NF-00336) concerns only the aerial parts and lists them as not novel in food. That entry notes that use of the aerial parts is known in food supplements and as an ingredient in tea.
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