Stinging Nettle (Urtica dioica): Uses, Evidence and Safety

Key points first

• Nettle root and nettle leaf are listed for different uses in the EU monographs: the root for prostate symptoms, and the leaf for minor urinary complaints, minor joint pain and a skin condition. [1] [2]
• The US National Center for Complementary and Integrative Health (NCCIH) calls the evidence for prostate symptoms limited. [3]
• If you have trouble urinating, blood in the urine, fever or pain, see a clinician first. The EU herbal monograph says serious conditions should be excluded by a doctor before using root products for prostate symptoms. [1]
• Pregnancy and breastfeeding: the EU monograph for nettle herb says safety has not been established and use is not recommended. [2]
• Nettle may interact with medicines in theory (diuretics, blood pressure medicines, medicines processed by liver enzymes). A hospital cancer center says the clinical relevance is not yet determined. [4]

Overview

Stinging nettle is a perennial plant native to Asia, Europe and North America. [4] Its root is widely used for benign prostatic hyperplasia (BPH, a non-cancerous enlarged prostate), allergies, arthritis and inflammation. [4] Nettle is often combined with herbs such as saw palmetto and pygeum for BPH. [4] For the tea as a drink, see nettle tea. On prostate herbs as a group, see herbs for prostate and urinary symptoms.

Names and plant parts

The accepted scientific name is Urtica dioica L., in the nettle family (Urticaceae). [5] The EU monographs cover both Urtica dioica and a second species, Urtica urens. [1] The parts used are the aerial parts or leaf (herba) and the root (radix). [2] [1] Plant parts matter: a result for root extract does not apply to leaf tea. See plant parts used in herbal products.

Traditional use (not proof of effect)

NCCIH says nettle roots have been used for urination disorders associated with BPH, as well as for joint problems, as a diuretic and as an astringent. [3] The European Medicines Agency (EMA) lists the root for lower urinary tract symptoms related to BPH, and the leaf or herb for minor urinary complaints, minor joint pain and seborrhoeic skin conditions. Each is a traditional herbal medicinal product based only on long-standing use, not on proof of effect. [1] [2]

What research shows

Forms and why the form matters

Products include dried herb for infusion, root extracts in solid or liquid forms, and freeze-dried preparations. [1] [9] The EU root monograph alone lists many different extract types. [1] Because trials used different extracts, a result for one product does not carry over to another. This page gives no amounts for a reader. A clinician or pharmacist decides what is right for a person.

Safety

• Common effects: the EU monographs list nausea, stomach upset, diarrhea and allergic reactions (itching, rash, hives). [1] [2] NCCIH says nettle seems generally well tolerated in trials. [3]
• Pregnancy and breastfeeding: the EU monograph for nettle herb says safety has not been established and use is not recommended. [2] A lactation database notes only minimal scientific support for a milk-supply effect, and suggests it is probably best not to apply nettle to the breast while breastfeeding, because one infant developed an allergic rash after a mother applied it to her nipple. [11] See pregnancy and breastfeeding.
• Fluid restriction: the EU monograph for nettle herb says it is not recommended for people whose conditions call for reduced fluid intake. [2]
• Blood sugar medicines: a cancer center review lists a case of low blood sugar in a 78-year-old man after he took an herbal remedy containing nettle for BPH. The nettle product was a mixture, so the cause is not certain. [4] See supplements and diabetes medicines.
• Diuretics and blood pressure medicines: the same review says nettle could add to the effect of diuretics and blood pressure medicines in theory, based on animal studies, and that the clinical relevance is not yet determined. [4] See supplements and blood pressure and heart medicines.
• Medicines cleared by liver enzymes: animal studies suggest nettle may inhibit CYP450 enzymes, and the clinical relevance has not been determined. [4]
• Iron: NCCIH notes a 2015 review saying nettle contains tannins, which can interact with iron and reduce its effect in people who need iron supplements. [3]
• Other case reports: breast enlargement in a man and milk flow in a woman with nettle tea; allergic rhinitis from nettle pollen. [4]
• EU monograph interactions: "none reported" for both root and herb. [1] [2]
• Children: the EU root monograph says there is no relevant use in children and adolescents under 18, and the herb monograph says use in children under 12 has not been established. [1] [2]
• Lithium, surgery, liver and kidney disease: not described in the sources we read. Lithium has a narrow safe range, so ask a pharmacist (narrow-range medicines). Tell the surgical team about any herb (supplements before surgery).
• Quality: see quality testing and certifications.