Stinging Nettle (Urtica dioica)

Nettle leaf/aerial is best framed as a mineral-rich nutritive + gentle anti-inflammatory + mild diuretic/urinary “flushing” herb, with common adjunct use in seasonal allergy symptoms and minor musculoskeletal discomfort. EMA recognizes traditional use for minor articular pain and urinary tract flushing as an adjunct in minor urinary complaints.

Nettle root is used primarily for lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH); EMA’s updated EU monograph (Revision 1, 2025) lists traditional use for LUTS/BPH after serious conditions have been excluded.

Identification & materia medica notes

• Botany: Herbaceous perennial with characteristic stinging trichomes (fresh plant contact can cause dermatitis/urtication). Processed/dried internal preparations do not sting.
• Taste/energetics (clinical shorthand): Leaf is typically cooling, drying-to-neutral, “building” (mineral/nutritive); root is more grounding/tonic to the lower urinary tract.

Constituents (clinically useful groupings)

Leaf / aerial

• Polyphenols/flavonoids (anti-inflammatory signaling support; antioxidant profile)
• Chlorophyll/carotenoids and “green” phytonutrients
• Mineral-rich (soil/harvest dependent; often leveraged clinically as a nutritive)
  A detailed nutrition/chemistry review highlights nettle’s nutrient density and phenolic content.

Root

• Lignans, phytosterols, polysaccharides and related fractions investigated in prostate/LUTS formulas (multi-target activity; not a single-constituent herb).

Pharmacology (selected, clinically relevant)

Anti-inflammatory activity (leaf): Experimental data suggest modulation of inflammatory pathways including NF-κB signaling (mechanistic support consistent with traditional “rheumatic” use—translate cautiously to clinical outcomes).

Urinary effects (leaf): Mild diuretic/“flushing” use is recognized in EMA’s traditional-use monograph.

LUTS/BPH symptom support (root): EMA’s 2025 EU monograph supports traditional use for LUTS/BPH (after exclusion of serious pathology) and provides dosing parameters and monitoring cautions.

Indications (by part)

A) Leaf / aerial (Urticae folium/herba)

Traditional-use indications (EMA)

• Minor articular pain
• Increase urine output to flush the urinary tract as an adjunct in minor urinary complaints

Common clinical adjunct uses (label/monograph support in Canada)

• Nutritive tonic
• Seasonal allergy symptoms (e.g., allergic rhinitis support)

B) Root (Urticae radix)

• Relief of LUTS related to BPH (traditional use; serious conditions excluded by a medical doctor)

Evidence notes (what to tell yourself clinically)

• EMA monographs = traditional-use framework (not the same as “proven efficacy,” but indicates longstanding use and reasonable safety when used appropriately).
• For LUTS/BPH, clinical trials frequently evaluate combination products (not nettle root alone). NCCIH’s professional digest summarizes research including Sabal (saw palmetto) + Urtica combinations and comparative trials.

Dosing (adult) — practical dispensing ranges

Adjust to extract ratio/standardization, patient constitution, and concurrent meds.

Leaf / aerial (EMA traditional-use dosing anchors)

• Infusion (tea): 2–4 g per dose, 3–6×/day (total 8–12 g/day)
• Liquid extract (example in EMA): “30–40 drops 3–4×/day” (product-dependent)
• Duration (EMA): articular pain ≤4 weeks; urinary flushing ≤2–4 weeks (then reassess).

Clinician pearl (nutritive strategy): Consider a long infusion (several hours) for mineral/nutritive emphasis if tolerated and appropriate for fluid status.

Root (EU monograph Revision 1, 2025 — examples)

• Comminuted root as “herbal tea” preparation: 300 mg twice daily (daily 600 mg)
• Dry extracts (examples): 460 mg once daily (or product-specific regimens; some monograph examples include higher dosing at start of treatment)
• Duration: “Long-term use is possible” with appropriate precautions/monitoring.

Safety, contraindications, cautions

Contraindications

• Hypersensitivity to nettle (leaf or root).

Key cautions

• When reduced fluid intake is recommended (e.g., severe cardiac/renal disease): avoid diuretic/flushing strategies with leaf.
• Pregnancy/lactation: EMA leaf monograph does not recommend use due to insufficient data; Health Canada monograph similarly advises avoid in pregnancy/breastfeeding for labeled products.
• Pediatrics: EMA leaf monograph: not recommended <12 years; EU root monograph: no relevant use <18 years.

Adverse effects

• Generally mild: GI upset; possible skin reactions (rash/urticaria) even with non-contact exposure in sensitive individuals.

Interactions (clinical practicality)

• EMA monographs list no known interactions, but real-world caution is reasonable with:
  • Diuretics / antihypertensives: possible additive effects (theoretical/animal; clinical relevance uncertain).
  • CYP450 substrate drugs: theoretical interaction based on animal data; clinical relevance uncertain.

Red flags & referral triggers

Leaf (urinary flushing / joint pain)

• Urinary symptoms with fever, dysuria, spasm pain, hematuria, or retention → urgent evaluation.
• Joint pain with swelling, redness, or fever → evaluate.

Root (LUTS/BPH)

• New/worsening LUTS, hematuria, recurrent UTIs, constitutional symptoms, or concerning PSA/DRE history → medical workup. (EU monograph emphasizes exclusion of serious conditions by a physician.)