Stinging Nettle

📜 Historical Use

Nettle has been more useful as cloth and as food than as medicine for most of its recorded history. The stems carry a bast fibre traditionally worked like linen; Bronze Age nettle textiles have been identified in Denmark, a nettle-fibre sash was recovered from a Bronze Age burial cist on Whitehorse Hill, Dartmoor, and the plant has been used for clothing for close to three thousand years. The widely repeated claim that German Army uniforms in the First World War were almost all made from nettle is, by contrast, poorly evidenced. As food, young leaves are eaten as a leaf vegetable once cooking or soaking has destroyed the stinging chemicals: nettle soup across Northern and Eastern Europe, dough fillings in Albanian, Balkan and Greek cooking, and spring harvesting by many Native American communities. The medicinal record is older than the supplement aisle. Nettle is one of the nine plants invoked in the Anglo-Saxon Nine Herbs Charm, recorded in tenth-century traditional medicine, and it was long believed to be a galactagogue. Urtication - deliberately applying stinging nettles to the skin to provoke inflammation - was a folk treatment for rheumatism, the sting used as a rubefacient; the same practice was reported in Ecuador in 2010 as a judicial punishment.

📊 What the Research Shows

This page is titled and categorised for seasonal allergies, and that is the single use where the evidence is weakest. MSK cites no clinical evidence for allergic rhinitis at all and states that evidence is lacking to support the claim; the support is in vitro only. Chest congestion and muscle spasms are listed the same way. The better-studied use is benign prostatic hypertrophy, with an important caveat: nettle root is usually given combined with saw palmetto and pygeum, and the positive results belong to those combinations. A saw palmetto plus nettle product reduced nighttime urination compared with placebo and performed similarly to tamsulosin or finasteride in moderate to severe symptoms, but the monograph does not describe the evidence for nettle used alone. In osteoarthritis the data are limited: trials cover hip, knee and hand, one tested a nettle sting applied to the base of the thumb, and a gonarthritis study used a multi-herb product. Topical use is described as supported by clinical trials, with larger studies still needed. For diabetes, one randomised placebo-controlled trial in advanced type 2 diabetes reported improved glycaemic control with a leaf extract, and the monograph says more studies are needed. Anticancer effects are laboratory findings only - clinical trials have yet to be conducted.

Take 300-500mg freeze-dried nettle leaf extract at the onset of symptoms, or drink nettle infusion daily.

Fresh leaves sting. Acts as a mild diuretic; ensure adequate water intake.

⚠️ What happens if taken in excess:

Excessive consumption (>3g extract/day) may cause significant fluid loss due to strong diuretic effects, leading to dehydration and electrolyte imbalances. High doses can lower blood sugar and blood pressure excessively. Fresh nettle contact causes painful stinging; consuming the raw unprocessed plant can irritate the throat and digestive tract.

The monograph's do-not-take list has exactly two entries, and both are worth stating precisely rather than softening. First, CYP450 substrate drugs: animal studies suggest nettle inhibits CYP450 enzymes and may therefore alter blood levels of drugs cleared by them. No individual isoenzyme is named - not CYP3A4, not CYP2D6 - and the clinical relevance is undetermined, so anyone checking a specific medication is working from animal data about a whole enzyme family rather than a measured human interaction. Second, diuretics and blood-pressure drugs: nettle may have an additive diuretic effect, and animal studies suggest a hypotensive action that may enhance antihypertensive drugs. Clinical relevance is again labelled undetermined. Tamsulosin and finasteride appear in this literature only as comparator drugs in BPH trials, not as documented interactions, and should not be listed as such. Warfarin and other anticoagulants, lithium and sedatives are absent from this source entirely, so no interaction with them should be claimed on this page. The combination that deserves watching on the record as it stands is glucose-lowering treatment: a hypoglycaemia case report and in vitro alpha-glucosidase and alpha-amylase inhibition point the same way, although the source names no specific diabetes drug.

1. Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis — Mittman P Planta Med (1990)[PubMed ↗]
2. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized study — Safarinejad MR J Herb Pharmacother (2005)[PubMed ↗]