Horsetail

Equisetum arvense · an ancient plant, valued for its silica

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Horsetail is a living fossil with a gritty feel — that grit comes from unusually high silica levels in the plant. This page explains what horsetail contains, how regulators view it, and the safety points that matter for supplements.

This article describes field horsetail (Equisetum arvense), its notable silica content and other constituents, how WellsparQ lists it in product labelling, the regulatory context for traditional herbal use, and the practical safety cautions consumers should know. It avoids making unauthorised health claims and states plainly where regulatory wording applies.

Ingredient Snapshot

What it is

A jointed, ancient fern‑relative plant valued for its high silica content.

Where from

Equisetum arvense (field horsetail)

Known for

Noted for an unusually high content of silica and flavonoids in its tissues.

In WellsparQ

• JointEase BlendHorsetail — 50 mg

Horsetail is one of the oldest plants still growing. Equisetum arvense — field horsetail — belongs to a lineage that predates flowering plants entirely, a survivor of forms that covered the earth long before grasses existed. It grows as jointed, feathery green stems with no true leaves or flowers, and it has a long place in European folk practice. In supplements it is valued for one distinctive feature of its chemistry: an unusually high content of silica. This page sets out the plant, that chemistry, the regulatory record, the safety points that genuinely matter, and how WellsparQ declares it — as information and evidence, not as a claim.

A living fossil, and why it is gritty

Handle dried horsetail and it feels faintly abrasive — historically the plant was used to scour pots and polish wood, which is where the old name "pewterwort" comes from. That grittiness is silica. Horsetail accumulates silicon from the soil and deposits it as hydrated silica in its tissues to an unusual degree, making it one of the richest botanical sources of the mineral ^¹. Alongside the silica sit flavonoids and other plant acids ^¹.

Silicon's precise role in human nutrition is still being worked out; it is present in connective tissue and bone, and dietary silicon has been studied in relation to bone and connective-tissue biology, but it is not classed as an essential nutrient with a settled requirement ^¹. That is an honest statement of where the science stands.

How WellsparQ declares it

Horsetail appears in a single WellsparQ formula, as a small declared note.

Source: WellsparQ Supplements Database. It is a modest, weighed addition to a joint-themed formula — named on the label like everything else, not hidden in a proprietary blend. As a botanical, horsetail is suitable for vegetarians and vegans.

The regulatory record

Horsetail is among the botanicals with a formal European document: the EMA Committee on Herbal Medicinal Products (HMPC) has published a herbal monograph on Equisetum arvense L., herba ^². As with other such monographs, it classifies horsetail preparations as traditional herbal medicinal products, a status based on long-standing use (at least 30 years, including 15 in the EU) and plausibility rather than on confirmatory clinical trials. The traditional-use indication it records is as an aid to irrigation of the urinary tract — increasing the volume of urine to help flush the tract — as adjuvant use in minor urinary complaints, and to support renal elimination of water ^².

This is a regulatory and historical statement about a class of registered traditional herbal medicines. It is not a WellsparQ food-supplement claim, and we do not present it as one.

Safety — the points that genuinely matter

Horsetail carries two specific cautions worth stating plainly rather than burying.

Correct species matters. Equisetum arvense must be distinguished from marsh horsetail, Equisetum palustre, which contains toxic alkaloids and can contaminate poorly sourced material ^¹². Reputable supplement horsetail should be from a controlled E. arvense source — a point of sourcing discipline, not a selling line.

Thiaminase. Horsetail naturally contains thiaminase, an enzyme that breaks down thiamine (vitamin B1). Reputable extracts are typically treated so the enzyme is inactivated, but prolonged or high use of untreated material is a theoretical route to thiamine depletion ^². For this reason horsetail is not recommended for long, unbroken use, and the HMPC records use for a limited period.

Because of these points, and because safety in pregnancy and breastfeeding is not established, those groups, anyone on medication (including diuretics or lithium), and anyone with a kidney or heart condition should ask a GP or pharmacist before using horsetail ^².

Where it fits

Horsetail is a genuinely ancient plant with a distinctive mineral chemistry and a long folk record — here a small, declared 50 mg note in a joint-themed blend. We describe its silica, its traditional-use status and its real cautions, and we stop there: rooted in nature, backed by what the research and the monograph actually say, and no further.