Herbal Monograph
Stinging Nettle
Urtica dioica L.
Urticaceae
A mineral-rich nutritive powerhouse with dual applications — leaf for allergies and inflammation, root for prostate health.
Overview
Plant Description
Perennial herbaceous plant, 60-200 cm tall, with vigorous creeping rhizomatous rootstock enabling extensive colonial spread. Stems erect, unbranched or sparingly branched, square in cross-section, covered with stinging hairs (trichomes) and shorter non-stinging hairs. Stinging trichomes are hollow, silicified, needle-like structures with a bulbous base containing a cocktail of irritant compounds (histamine, acetylcholine, serotonin, formic acid, leukotrienes). Upon contact, the brittle silica tip breaks off and the hair acts as a hypodermic needle, injecting irritants into the skin. Leaves opposite, ovate to lanceolate, 3-15 cm long, 2-8 cm wide, with deeply serrate margins, cordate base, and acuminate apex. Leaves are dark green, with prominent venation and stinging hairs on both surfaces. Stipules present, narrow, 5-15 mm long. Plant is dioecious (separate male and female plants), though monoecious forms occur. Inflorescences are axillary, pendulous, catkin-like panicles. Male flowers have 4 tepals and 4 stamens that spring open explosively to release pollen. Female flowers have 4 tepals (inner pair larger, enclosing the achene). Fruit a small, ovoid achene, 1-1.5 mm long, enclosed by persistent perianth. Root system consists of extensive, bright yellow, creeping rhizomes with abundant fine rootlets.
Habitat
Highly adaptable, found in temperate and subtropical regions across the Northern Hemisphere. Thrives on rich, moist, nitrogen-rich soils -- it is a strong indicator of high soil nitrogen and phosphorus, often found near human habitation, farmyards, ruins, and disturbed ground. Prefers partial shade to full sun. Common in hedgerows, woodland margins, riverbanks, floodplains, waste ground, and roadside verges. Tolerates a wide pH range (5.0-8.0) but prefers slightly acidic to neutral soils. Grows from sea level to approximately 2400 m altitude in Europe.
Distribution
Native to Europe, Asia, northern Africa, and western North America. Naturalized and widespread in temperate regions worldwide. Found across all of Europe from Scandinavia to the Mediterranean, through Russia and Central Asia to the Himalayas and western China. The subspecies U. dioica subsp. gracilis is native throughout North America. Now naturalized in South America, southern Africa, Australia, and New Zealand. Essentially cosmopolitan in temperate zones. Wild-harvested throughout its range; commercial cultivation exists in Europe (particularly Germany, Hungary, Poland) and to a lesser extent in North America.
Parts Used
Aerial parts / Leaf (Urticae folium / Urticae herba)
Preferred: Infusion (tea), dried leaf capsule, freeze-dried leaf capsule, tincture, fresh cooked as vegetable
The most widely used part in Western herbal practice. Rich in minerals (iron, calcium, silica, potassium, magnesium), chlorophyll, carotenoids, flavonoids (quercetin, kaempferol, rutin), and vitamins (A, C, K). The leaf is used for its diuretic, anti-inflammatory, alterative, astringent, and nutritive properties. Commission E approved for supportive treatment of rheumatic complaints and as irrigation therapy for urinary tract inflammation and prevention of kidney gravel. WHO monograph covers the leaf/aerial parts. The fresh plant retains stinging capacity; dried or cooked leaf does not sting.
Root (Urticae radix)
Preferred: Standardized root extract (capsule), tincture of dried root, decoction
Phytochemically distinct from the leaf. Contains beta-sitosterol, scopoletin, lignans (including secoisolariciresinol and its diglucoside), polysaccharides (with immunostimulant properties), and Urtica dioica agglutinin (UDA, a lectin). The root is specifically used for benign prostatic hyperplasia (BPH) symptoms and has been approved by Commission E for this indication. Root extracts interact with sex hormone-binding globulin (SHBG), inhibit 5-alpha-reductase, and inhibit aromatase, all of which are relevant to BPH pathophysiology. Root preparations are NOT interchangeable with leaf preparations.
Fresh plant juice (Urticae herba succus)
Preferred: Stabilized fresh juice (Presssaft), 10-15 mL 3 times daily
Expressed juice of the fresh aerial parts. Used in some European phytotherapy traditions. Contains the full spectrum of leaf constituents in a readily bioavailable liquid form. Some German phytotherapy products use stabilized fresh plant juice (Presssaft). Used for spring cleansing cures and as a nutritive tonic. Fresh juice retains vitamin C which is partially degraded in dried preparations.
Key Constituents
Minerals and trace elements
The exceptional mineral content is the foundation of nettle's reputation as a nutritive tonic and alterative. The high iron and vitamin C combination makes it particularly relevant for iron-deficiency states. The potassium content is clinically significant because it mitigates the potassium-depleting effects typically associated with diuretic therapy. The mineral profile also supports the traditional use of nettle for hair, skin, nail, and bone health.
Flavonoids
Flavonoids, particularly quercetin, are considered primary contributors to nettle leaf's anti-inflammatory and antiallergic activity. Roschek et al. (2009) identified multiple bioactive compounds in nettle leaf extract that antagonize the H1 receptor, inhibit mast cell tryptase, and inhibit prostaglandin formation -- with quercetin and flavonoid-related compounds being key active fractions. The antihistamine mechanism of quercetin provides a pharmacological rationale for the traditional and clinically observed efficacy of freeze-dried nettle leaf in allergic rhinitis.
Chlorophyll and carotenoids
The high chlorophyll content underpins nettle's traditional use as a spring tonic and blood-building herb. While the direct hematopoietic effect of chlorophyll itself is debated, the combination of chlorophyll, iron, vitamin C, and folic acid in nettle leaf creates a phytochemical matrix supportive of red blood cell formation. Carotenoids contribute to antioxidant and tissue-protective effects.
Lectins and polysaccharides (primarily in root)
UDA is a unique immunologically active lectin. Its immunomodulatory properties include stimulation of T-lymphocyte proliferation and modulation of cytokine profiles. The polysaccharides contribute to immune support and anti-inflammatory activity. These constituents are concentrated in the root and are relevant to both the BPH and immunomodulatory applications of nettle root preparations.
Phytosterols and lignans (primarily in root)
The phytosterol and lignan content of nettle root provides the pharmacological basis for its use in BPH. Multiple mechanisms are involved: beta-sitosterol directly inhibits 5-alpha-reductase and aromatase; lignans bind SHBG, modulating free hormone levels; and the combined anti-inflammatory effects reduce prostatic inflammation. These root-specific constituents are the reason that root preparations (not leaf) are used for BPH. The Cochrane-reviewed studies on BPH primarily used standardized root extracts.
Other constituents
The vitamin content reinforces nettle's role as a nutritive herb, particularly the iron-vitamin C-folic acid combination for blood building. Vitamin K content is clinically relevant regarding anticoagulant interactions. The stinging hair compounds, while an irritant from a safety perspective, are therapeutically exploited in the traditional practice of urtication for arthritis -- the counter-irritant, histamine-mediated vasodilation and pain-gate mechanism may explain the traditional efficacy reported for this practice.
Herbal Actions
Increases urine production and output
One of nettle leaf's best-established actions, approved by Commission E and included in the WHO monograph. Nettle leaf promotes increased urine volume and is used as irrigation therapy (Durchspulungstherapie) for urinary tract inflammation and prevention/treatment of kidney gravel. The diuretic mechanism is aquaretic (increases water excretion) rather than saluretic. Importantly, the high potassium content of nettle leaf provides natural potassium replacement, unlike most pharmaceutical diuretics. ESCOP recommends nettle herb for irrigation therapy in inflammatory conditions of the lower urinary tract.
[1, 2, 3]Reduces inflammation
Demonstrated in both leaf and root preparations through multiple mechanisms. Leaf: flavonoids (particularly quercetin) inhibit COX-2, 5-LOX, and NF-kB signaling. Nettle leaf extract has been shown to inhibit the enzymatic activity of cyclooxygenase and to suppress pro-inflammatory cytokine release (TNF-alpha, IL-1beta). Riehemann et al. (1999) demonstrated that nettle leaf extract inhibits NF-kB activation, a central transcription factor in the inflammatory cascade. Root: polysaccharides and scopoletin contribute anti-inflammatory activity relevant to prostatic inflammation. The dual leaf/root anti-inflammatory activity supports the traditional uses in both rheumatic conditions and urinary/prostatic complaints.
[8, 10, 12]Tightens and tones tissue, reduces secretions
Attributed to tannin and flavonoid content. Traditional use for controlling excessive bleeding (menorrhagia, nosebleeds, hemorrhoids) and reducing secretions. The vitamin K content may contribute to hemostatic effects. Astringent properties support the traditional use of nettle for diarrhea and for topical application to weeping eczema and skin conditions.
[11, 12]Gradually restores proper body function and increases overall health
A cornerstone traditional action. Nettle is considered one of the premier alterative ('blood-cleansing') herbs in Western herbal practice. The alterative action is attributed to the synergistic combination of mineral nutrition, diuretic waste elimination, anti-inflammatory activity, and liver/kidney support. Traditionally used in spring cleansing cures across European herbalism. The rich nutritive profile (iron, minerals, chlorophyll, vitamins) combined with gentle detoxification support through diuresis makes nettle a classical alterative for chronic skin conditions, arthritis, and general debility.
[11, 12]Modulates and balances immune function
Attributed primarily to UDA (Urtica dioica agglutinin) and polysaccharide fractions in the root, and to flavonoid and phenolic acid content in the leaf. UDA demonstrates T-cell modulatory activity. Polysaccharide fractions show immunostimulant properties in vitro. The leaf's antihistamine and anti-inflammatory effects (mast cell stabilization, histamine receptor antagonism) represent immunomodulatory activity in the context of allergic/atopic conditions. Overall effect is modulating rather than simply stimulating.
[8, 12]Relieves pain
Anti-inflammatory-mediated pain relief is demonstrated in clinical trials for osteoarthritis and rheumatic conditions. Additionally, the traditional practice of urtication (deliberate stinging of affected joints with fresh nettle) provides counter-irritant analgesia through a complex mechanism involving histamine-mediated vasodilation, substance P depletion, and pain-gate effects. Randall et al. (2000) RCT demonstrated that urtication of the thumb base with fresh nettle significantly reduced osteoarthritis pain compared to placebo (dead nettle/Lamium album).
[7, 8]Lowers blood pressure
Mild blood-pressure-lowering effect attributed to diuretic action and possible direct vascular effects. Animal studies have demonstrated hypotensive activity. Nettle's aquaretic diuretic action reduces blood volume, contributing to modest blood pressure reduction. Clinical evidence for standalone antihypertensive use is limited, but the effect is relevant as a potential drug interaction with antihypertensive medications.
[2, 12]Therapeutic Indications
Urinary System
Benign prostatic hyperplasia / BPH (root preparation)
Commission E approved indication for nettle root. Safarinejad 2005 double-blind RCT (n=558, 6 months): nettle root extract (120 mg tid) significantly improved IPSS (International Prostate Symptom Score), Qmax (peak urinary flow rate), and post-void residual volume compared to placebo. Multiple mechanisms: beta-sitosterol inhibits 5-alpha-reductase, lignans bind SHBG, polysaccharides reduce prostatic inflammation. Often combined with Serenoa repens (saw palmetto) for synergistic BPH activity. Chrubasik et al. 2007 systematic review confirmed evidence for symptomatic BPH relief. NOTE: Nettle root improves symptoms of BPH but does not reduce prostate size. Patients should be medically evaluated to rule out prostate cancer before using nettle root for urinary symptoms.
[1, 5, 8]Urinary tract irrigation / inflammatory conditions of lower urinary tract
Commission E approved indication for nettle leaf/herb: 'irrigation therapy for inflammatory diseases of the lower urinary tract and prevention and treatment of kidney gravel.' Nettle's aquaretic diuretic action increases urine volume, which mechanically flushes the urinary tract, reduces bacterial adherence, and dilutes urinary irritants. Used in combination with adequate fluid intake (at least 2 L/day). ESCOP and WHO monographs support this indication. Not a standalone antibiotic treatment for active UTI -- used as supportive/adjunctive therapy.
[1, 2, 3]Musculoskeletal System
Rheumatic conditions and osteoarthritis
Commission E approved for supportive treatment of rheumatic complaints. Both internal (leaf tea, extract) and external (urtication) applications have been studied. Randall et al. 2000 RCT: daily application of fresh stinging nettle to the base of the thumb for 1 week significantly reduced pain and disability in thumb/finger OA compared to dead nettle (Lamium album) placebo. Anti-inflammatory mechanisms (NF-kB inhibition, COX/LOX inhibition) provide pharmacological rationale. Chrubasik et al. 2007 review found supportive evidence for leaf extract in musculoskeletal pain. Traditional urtication therapy (deliberate stinging of arthritic joints) has been practiced across European folk medicine for centuries and is experiencing renewed clinical interest.
[1, 7, 8]Gout (adjunctive support)
Traditional use of nettle leaf tea for gout, attributed to its combined diuretic (promotes uric acid excretion) and anti-inflammatory actions. The alkalinizing mineral content may also contribute. No rigorous clinical trials specifically for gout, but the pharmacological rationale (diuresis, anti-inflammatory, mineralization) is consistent with traditional claims.
[11, 12]Immune System
Seasonal allergic rhinitis (hay fever)
Mittman 1990 RCT (n=69): freeze-dried Urtica dioica leaf (300 mg capsule) significantly outperformed placebo for allergic rhinitis symptom relief, with 58% of participants rating it effective and 48% rating it equal to or better than their previous medication. Roschek et al. 2009 identified multiple anti-allergic mechanisms in nettle leaf extract: H1 receptor antagonism, inhibition of mast cell tryptase, inhibition of prostaglandin formation, and inhibition of histamine release. Quercetin (a major nettle flavonoid) is a known mast cell stabilizer. The freeze-dried preparation appears to retain the bioactive compounds more effectively than simple dried leaf. Used prophylactically and acutely during allergy season.
[6, 9]Reproductive System
Menorrhagia and excessive uterine bleeding (traditional use)
Long-standing traditional use of nettle leaf for reducing heavy menstrual bleeding, attributed to its astringent and hemostatic properties. The vitamin K content may contribute to hemostatic activity. Used in Western herbal practice as part of formulas for menorrhagia, often combined with other astringent herbs (e.g., Achillea millefolium, Capsella bursa-pastoris). Limited clinical evidence specifically for this indication, but the pharmacological rationale (astringent, vitamin K, hemostatic) is established.
[11, 12]Skin / Integumentary
Chronic skin conditions (eczema, acne) as alterative therapy
Traditional use of nettle leaf as an alterative ('blood cleanser') for chronic skin conditions. The rationale combines diuretic-mediated waste elimination, anti-inflammatory activity, nutritive support (particularly minerals and vitamins for tissue repair), and mild hepatoprotective effects. Used in European naturopathic medicine as a component of depurative (cleansing) regimens for chronic eczema, acne, and urticaria. Typically used as long-term therapy (weeks to months) rather than acute treatment. Often combined with other alteratives such as Arctium lappa (burdock) or Galium aparine (cleavers).
[11, 12]Hair loss and scalp health (traditional use)
Traditional topical and internal use of nettle for hair loss and scalp conditions. The silica, mineral, and anti-inflammatory content may support hair follicle health. Nettle root extract, through its 5-alpha-reductase inhibition and SHBG binding, has theoretical relevance to androgenetic alopecia via the same mechanisms as its BPH activity. Some commercial hair care products contain nettle extract. Clinical evidence for hair loss is limited to small, poorly controlled studies.
[12]Digestive System
Nutritional supplementation and iron-deficiency support
Nettle leaf is one of the most nutrient-dense herbs in the Western materia medica. Its exceptional iron content (combined with vitamin C and folic acid for enhanced absorption) makes it a traditional remedy for mild iron deficiency and the fatigue associated with it. Used extensively as a nutritive tonic during pregnancy (under practitioner guidance), postpartum recovery, and convalescence. Typically consumed as a strong infusion (tea) or as cooked greens. Not a substitute for iron supplementation in severe deficiency, but a valuable dietary and botanical adjunct to support healthy iron levels.
[11, 12]Energetics
Temperature
cool
Moisture
dry
Taste
Tissue States
damp/stagnation, hot/excitation
Nettle is generally classified as cool and dry in Western energetic herbalism, though some practitioners consider it more neutral-to-slightly cool. The mildly astringent, salty, and bitter taste profile reflects its high mineral and tannin content. The cooling and drying qualities make it appropriate for damp and hot tissue states -- conditions with inflammation, swelling, fluid retention, and weeping discharges. In Ayurvedic terms, nettle would be considered to reduce pitta and kapha while potentially aggravating vata if used excessively or in already dry/cold constitutions. The salty taste from its mineral content is unusual among herbs and reflects its exceptional nutritive value. Nettle's traditional role as a spring tonic and blood cleanser aligns with its ability to clear damp-heat patterns.
Traditional Uses
European Folk Medicine / Western Herbalism
- Spring tonic and blood purifier: nettle leaf tea or cooked greens consumed in spring to 'cleanse the blood' after winter -- one of the most widespread folk uses across all of Europe
- Urtication therapy: deliberate stinging of arthritic or rheumatic joints with fresh nettle to relieve pain and inflammation -- practiced across Europe from antiquity through the present day
- Diuretic and kidney support: infusion used to promote urination, treat edema, and prevent kidney stones
- Iron tonic for anemia, weakness, and fatigue: strong infusion or cooked greens as a nutritive remedy, especially for women and during pregnancy
- Astringent for hemorrhage: leaf tea or juice used internally for nosebleeds, heavy menstrual bleeding, and hemorrhoids
- Skin conditions: alterative tea for chronic eczema, acne, and urticaria as part of depurative (cleansing) cures
- Hair rinse: strong nettle tea used as a final hair rinse to strengthen hair and treat dandruff
- Food plant: young nettle tops cooked as a vegetable (similar to spinach) or made into soup across much of Northern and Eastern Europe
"Nettle has one of the longest documented histories of any European medicinal plant. Pliny the Elder (Natural History, 77 CE) described urtication therapy for paralysis and joint pain. Dioscorides (De Materia Medica, c. 70 CE) recommended nettle leaf juice for nosebleeds, dog bites, and as an emmenagogue. Culpeper (1652) wrote that nettle 'consumes the phlegmatic superfluities in the body of man, that the coldness and moisture of winter has left behind.' Gerard's Herball (1597) documented nettle for 'those that are bitten with the venomous serpent' and as a diuretic. The use of nettle as a spring tonic and food plant is universal across European folk traditions from Scandinavia to the Mediterranean."
Native American Medicine
- Rheumatic pain relief through urtication (stinging of painful joints with fresh nettle) -- documented among several tribes
- Fiber plant: nettle stem fibers used for cordage, fishing nets, and textile production
- Food plant: young shoots cooked as greens by numerous Pacific Northwest and Eastern Woodland tribes
- Childbirth support: nettle tea used to strengthen the uterus and reduce postpartum hemorrhage
- Hair and scalp treatment: nettle rinse used for hair health
- Diuretic for urinary complaints
"The North American subspecies (U. dioica subsp. gracilis) was widely used by indigenous peoples across the continent. Moerman's 'Native American Ethnobotany' documents extensive use by Coast Salish, Cowlitz, Makah, Quinault, and numerous other tribal groups for food, fiber, and medicine. Urtication for arthritis and rheumatism mirrors the European practice, suggesting independent discovery of this therapeutic approach. Nettle fiber was a major textile resource on the Pacific Northwest Coast prior to European contact."
[11]
Ayurveda and Traditional Indian Medicine
- Bichu buti (Hindi name): used for rheumatic and joint complaints
- Diuretic for urinary disorders and kidney support
- Anti-inflammatory for musculoskeletal pain
- Tonic for general weakness and debility
- Treatment of skin diseases including urticaria and eczema
"While not as prominent as in European herbalism, Urtica dioica grows in the Himalayan region and has been used in traditional Indian folk medicine and, to some extent, in Ayurvedic practice. In the Himalayan tradition, nettle (called bichu buti, kandali, or sisnu depending on the region) is used as food and medicine, with the young shoots being a staple vegetable in some hill communities. The plant is considered bitter and astringent in taste, with cooling potency."
[12]
Traditional Food Medicine (Pan-European)
- Nettle soup: a traditional spring dish across Scotland, Scandinavia, Germany, Poland, and many other European countries -- consumed as a food medicine for health restoration after winter
- Nettle beer and wine: traditional fermented beverages in Britain and Northern Europe
- Nettle cheese: used as a wrapping and flavoring for cheese production (e.g., Cornish Yarg, Gouda with nettles)
- Nettle porridge and bread: flour additive in times of scarcity
- Livestock feed: dried nettle added to animal feed to improve health and milk production
- Textile fiber: nettle stems processed for fiber to produce cloth (nettle cloth production documented from Bronze Age through World War I in Europe)
"The food use of nettle is inseparable from its medicinal use in European tradition. The concept of 'food as medicine' is nowhere more apparent than with nettle. The annual spring consumption of nettle greens across much of Europe represents one of the oldest continuing food-medicine practices on the continent. Archaeobotanical evidence suggests nettle was consumed in the European Bronze Age. During both World Wars, nettle was actively promoted as a food and fiber resource in Germany and Britain."
Modern Research
Systematic review of Urtica dioica for BPH and musculoskeletal conditions
Comprehensive systematic review of clinical evidence for Urtica dioica root extract in BPH and nettle leaf/herb in musculoskeletal conditions including osteoarthritis and rheumatoid arthritis.
Findings: For BPH: several clinical trials demonstrated significant improvements in IPSS, urinary flow rates, and post-void residual volume with nettle root extract compared to placebo. Combination with Serenoa repens (saw palmetto) showed additive benefit. For musculoskeletal conditions: evidence supported anti-inflammatory and analgesic effects of nettle leaf extract. The review concluded that nettle root preparations have a favorable benefit-risk profile for symptomatic BPH and that nettle leaf has promising evidence for anti-inflammatory indications.
Limitations: Heterogeneous study designs, variable preparations and doses, and generally small to moderate sample sizes. Many trials were conducted in Europe with limited geographic diversity. Long-term safety data beyond 6 months was limited.
[8]
Double-blind RCT of nettle root extract for BPH
Large, double-blind, placebo-controlled, randomized clinical trial of 558 patients with BPH. Patients received Urtica dioica root extract (120 mg three times daily) or placebo for 6 months.
Findings: Nettle root extract significantly improved IPSS (International Prostate Symptom Score) compared to placebo (P<0.001). Peak urinary flow rate (Qmax) improved significantly in the nettle group. Post-void residual volume decreased significantly. 81% of patients in the nettle group reported improvement in lower urinary tract symptoms compared to 16% in the placebo group. The extract was well-tolerated with only mild gastrointestinal side effects.
Limitations: Single-center study conducted in Iran. 6-month duration limits long-term efficacy and safety assessment. The substantial placebo response (16% improvement) is typical for BPH trials. Prostate volume was not significantly changed, indicating symptomatic rather than structural improvement.
[5]
Randomized controlled trial of stinging nettle for allergic rhinitis
Double-blind, randomized, placebo-controlled trial of 69 patients with allergic rhinitis. Patients received freeze-dried Urtica dioica leaf (300 mg capsule) or placebo at the onset of allergy symptoms.
Findings: After 1 week of treatment, 58% of the nettle group rated the product effective in relieving allergic rhinitis symptoms, compared to 37% in the placebo group. 48% of nettle users rated it equal to or better than their previously used allergy medication. Global assessments significantly favored nettle over placebo. The freeze-dried preparation was selected to preserve the heat-labile bioactive compounds.
Limitations: Relatively small sample size (n=69). Short study duration (1 week). Self-reported subjective outcomes. The specific freeze-dried preparation may not be representative of all nettle leaf products. No objective measures of nasal airflow or inflammatory markers were used.
[6]
Anti-allergic mechanisms of nettle leaf extract
In vitro mechanistic study identifying specific bioactive compounds in Urtica dioica leaf extract responsible for anti-allergic activity.
Findings: Nettle leaf extract demonstrated multiple simultaneous anti-allergic mechanisms: (1) antagonism of the H1 histamine receptor, (2) inhibition of mast cell tryptase (a protease involved in allergic inflammation), (3) inhibition of prostaglandin D2 formation via COX-1 and COX-2 inhibition, and (4) inhibition of histamine release from mast cells. The active compounds included quercetin and other flavonoid-related compounds. The multi-target anti-allergic activity provides pharmacological support for the clinical efficacy observed in allergic rhinitis trials.
Limitations: In vitro study: concentrations used may not reflect in vivo bioavailability. The specific extract tested may not represent all commercial nettle products. Translation from in vitro activity to clinical efficacy requires clinical validation.
[9]
Urtication (stinging nettle application) for osteoarthritis pain: RCT
Randomized, double-blind, crossover trial of 27 patients with osteoarthritis of the thumb base (trapeziometacarpal joint). Patients applied fresh Urtica dioica leaf (active urtication) or Lamium album (dead nettle/white nettle, visually similar but non-stinging as placebo) daily to the affected thumb for 1 week each.
Findings: Active nettle urtication significantly reduced pain (VAS score) and disability compared to placebo dead nettle application. Pain reduction persisted beyond the treatment period. The urtication was well-tolerated; the transient stinging and erythema were acceptable to most patients. The mechanism likely involves counter-irritation, histamine-mediated vasodilation, substance P modulation, and the pain-gate theory of sensory input competing with pain signals.
Limitations: Small sample size (n=27). Blinding may have been imperfect (patients could potentially distinguish stinging from non-stinging plants, though the dead nettle served as a credible placebo). Short treatment duration (1 week per intervention). Single joint studied. The practice requires access to fresh nettle plants, limiting generalizability.
[7]
NF-kB inhibition by nettle leaf extract: molecular anti-inflammatory mechanism
In vitro study investigating the molecular anti-inflammatory mechanism of Urtica dioica leaf extract, specifically its effect on NF-kB (nuclear factor kappa B) transcription factor activation.
Findings: Nettle leaf extract potently inhibited NF-kB activation in a dose-dependent manner. NF-kB is a master transcription factor that controls expression of multiple pro-inflammatory genes including TNF-alpha, IL-1, IL-6, COX-2, and iNOS. The extract prevented degradation of IkB-alpha (the inhibitory subunit that keeps NF-kB sequestered in the cytoplasm). This mechanism explains the broad anti-inflammatory effects observed clinically and provides a molecular rationale for nettle's efficacy in inflammatory conditions including arthritis and allergic responses.
Limitations: In vitro data from cell culture systems. Concentrations tested may not directly correspond to achievable tissue concentrations after oral administration. Specific active compounds responsible for NF-kB inhibition were not fully elucidated in this study.
[10]
Preparations & Dosage
Infusion (Tea)
Strength: 3-6 g dried leaf per 240 mL water (standard); 30 g per 1 L (strong nutritive infusion)
Steep 2-4 teaspoons (approximately 3-6 g) of dried nettle leaf in 240 mL (8 oz) of just-boiled water for 10-15 minutes, covered. Strain and drink. For a strong nutritive infusion (overnight infusion): place 30 g (approximately 1 oz) of dried nettle leaf in a quart jar, fill with boiling water, cap tightly, and steep for 4-8 hours (or overnight). Strain and drink throughout the next day, refrigerated.
Standard infusion: 1-2 cups (240-480 mL) 3 times daily. Nutritive overnight infusion: 1 quart (approximately 1 L) daily.
3 times daily for standard infusion. Daily for overnight nutritive infusion.
May be used long-term as a daily nutritive tonic. For allergies: begin 2-4 weeks before allergy season and continue through the season. For urinary irrigation: use for limited courses (2-4 weeks) with adequate fluid intake.
Children over 6: half adult dose. Not established for children under 6.
The most traditional and widely used preparation form. Hot water infusion effectively extracts minerals, flavonoids, chlorophyll, and vitamins. The strong overnight infusion method (popularized by herbalist Susun Weed) maximizes mineral extraction due to prolonged steeping time. Nettle tea has a pleasant, mildly grassy, spinach-like flavor. The diuretic effect is notable; ensure adequate fluid intake. For iron supplementation purposes, the strong infusion is preferred.
Capsule / Powder
Strength: Leaf: 300-600 mg freeze-dried per capsule. Root: typically 120-250 mg standardized extract per capsule.
For nettle LEAF: fill capsules with freeze-dried or dried powdered nettle leaf. For nettle ROOT: use standardized root extract capsules, typically standardized to beta-sitosterol content. Freeze-dried leaf capsules are specifically recommended for allergic rhinitis based on clinical trial evidence.
Leaf (general/allergies): 300-600 mg freeze-dried leaf, 2-3 times daily (600-1800 mg/day). Dried leaf powder: 2-4 g daily in divided doses (Blumenthal 2000). Root (BPH): 120 mg standardized root extract 3 times daily (360 mg/day), or 4-6 g crude dried root daily per European Pharmacopoeia and Commission E guidelines.
2-3 times daily for both leaf and root preparations
Leaf (allergies): throughout allergy season. Root (BPH): clinical trials have studied 6-month courses; long-term use may be appropriate under practitioner guidance. Ongoing medical monitoring of BPH symptoms recommended.
Not well-established for capsule forms in children.
Freeze-dried leaf capsules were specifically used in the Mittman 1990 allergic rhinitis trial and are preferred for allergy applications because freeze-drying preserves heat-labile bioactive compounds that may be degraded by conventional drying. Root capsules for BPH should be specifically standardized root extract (not leaf). IMPORTANT: Leaf and root preparations are not interchangeable -- they have different chemical profiles and different therapeutic indications.
Tincture
Strength: Dried leaf: 1:5, 45% ethanol. Dried root: 1:5, 45-60% ethanol.
Leaf tincture: Macerate dried nettle leaf in 45% ethanol at a ratio of 1:5 for 2-4 weeks. Shake daily. Press and filter. Root tincture: Macerate dried nettle root in 45-60% ethanol at a ratio of 1:5 for 4-6 weeks. The root requires longer maceration and may benefit from slightly higher alcohol percentage to extract lipophilic sterols and lignans.
Leaf: 2-5 mL (approximately 40-100 drops), 3 times daily. Root: 2-5 mL, 3 times daily.
3 times daily
Leaf: may be used long-term. Root: as appropriate for BPH symptom management.
Not recommended for children due to alcohol content (for leaf indications, infusion is preferred).
Tincture provides a convenient concentrated form. Leaf tincture is useful for general alterative and anti-inflammatory indications. Root tincture is used specifically for BPH. Alcohol extraction captures a broader range of constituents than water infusion, including more lipophilic compounds. However, for mineral-rich nutritive purposes, infusion is superior as minerals extract better into water.
Fresh Juice / Expressed Juice
Strength: Undiluted fresh pressed juice or commercially stabilized Presssaft
Harvest fresh young nettle tops (wearing gloves). Juice using a masticating juicer or blend with small amount of water and strain through cheesecloth. The stinging capacity is destroyed by the mechanical processing. Use immediately or stabilize by brief heating to 70C and refrigerating. In European phytotherapy, stabilized fresh plant juice (Presssaft) is a commercial preparation.
10-15 mL fresh juice, 3 times daily. Or 15-20 mL of commercial stabilized Presssaft, 3 times daily.
3 times daily
Traditionally used in spring cure regimens for 3-6 weeks.
Not established for young children. Older children (over 12): half adult dose if tolerated.
Fresh juice retains vitamin C and other heat-labile compounds that are partially lost in drying. Traditional spring cure (Fruhjahrskur) in German naturopathic medicine uses fresh nettle juice for 3-6 weeks as a depurative and alterative treatment. The German company Schoenenberger produces a standardized Presssaft that has been used in some clinical contexts. This preparation is less commonly available outside of Europe.
Safety & Interactions
Class 1
Can be safely consumed when used appropriately (AHPA Botanical Safety Handbook)
Contraindications
Rare but possible. Allergic reactions beyond the expected stinging hair irritation have been reported. Cross-reactivity within Urticaceae is theoretically possible but not well-documented.
Commission E and ESCOP state that nettle should not be used for irrigation therapy in cases of edema due to impaired heart or kidney function. The diuretic effect and increased fluid load associated with irrigation therapy could exacerbate fluid retention in the setting of cardiac or renal insufficiency. This contraindication applies specifically to the irrigation therapy indication (high-volume fluid intake with nettle), not to moderate consumption of nettle tea as a nutritive. The EMA assessment report concurs with this contraindication.
Drug Interactions
| Drug / Class | Severity | Mechanism |
|---|---|---|
| Warfarin and other vitamin K-sensitive anticoagulants (Anticoagulants) | moderate | Nettle leaf contains significant amounts of vitamin K, which promotes synthesis of coagulation factors II, VII, IX, and X. Vitamin K directly antagonizes the mechanism of action of warfarin. Adding or discontinuing regular nettle consumption can alter INR values. |
| Antihypertensive agents (ACE inhibitors, ARBs, calcium channel blockers, diuretics) (Antihypertensive agents) | minor | Nettle has mild hypotensive effects via its aquaretic diuretic action and possible direct vascular effects demonstrated in animal studies. Additive blood pressure lowering is pharmacologically plausible. |
| Pharmaceutical diuretics (furosemide, hydrochlorothiazide, spironolactone) (Diuretics) | minor | Additive diuretic effects. Nettle's aquaretic mechanism combined with pharmaceutical diuretics may increase total fluid and electrolyte loss. |
| Lithium (Mood stabilizers) | moderate | Diuretic herbs may decrease renal lithium clearance by promoting sodium and water excretion, which triggers compensatory lithium reabsorption in the proximal tubule. This can increase serum lithium levels. |
Pregnancy & Lactation
Pregnancy
likely safe
Lactation
likely safe
Pregnancy: Nettle leaf is traditionally used as a nutritive tonic during pregnancy, valued for its iron, calcium, vitamin K, and mineral content. The AHPA Botanical Safety Handbook classifies nettle leaf as class 1 (safe for appropriate use). However, some sources recommend caution due to traditional emmenagogue and uterine stimulant properties (attributed to the serotonin and histamine in fresh plant -- which are absent in dried preparations). Dried nettle leaf tea in moderate amounts is generally considered safe during pregnancy and is widely used by midwives and herbalists for prenatal nutritive support. Root preparations are not typically used during pregnancy (no pregnancy-related indication and insufficient safety data). Lactation: Nettle has a traditional reputation as a galactagogue (promotes breast milk production) and is widely consumed by breastfeeding women. No adverse effects on lactation or breastfed infants have been reported. Classified as likely-safe during lactation.
Adverse Effects
References
Monograph Sources
- [1] German Commission E (Bundesinstitut fur Arzneimittel und Medizinprodukte). Commission E Monographs: Urticae herba (Nettle Herb), Urticae folium (Nettle Leaf), and Urticae radix (Nettle Root) -- Positive. Bundesanzeiger (Federal Gazette) (1998)
- [2] World Health Organization. WHO Monographs on Selected Medicinal Plants, Volume 2: Radix Urticae / Herba Urticae dioicae. World Health Organization, Geneva (2002) : 329-341
- [3] European Scientific Cooperative on Phytotherapy (ESCOP). ESCOP Monographs: Urticae folium/herba -- Nettle Leaf/Herb; Urticae radix -- Nettle Root. ESCOP Monographs, 2nd edition. Thieme, Stuttgart (2003)
- [4] Committee on Herbal Medicinal Products (HMPC), European Medicines Agency. Assessment report on Urtica dioica L., Urtica urens L., folium. European Medicines Agency (2012)
Clinical Studies
- [5] Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. J Herb Pharmacother (2005) ; 5 : 1-11 . PMID: 16093232
- [6] Mittman P. Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis. Planta Med (1990) ; 56 : 44-47 . DOI: 10.1055/s-2006-960881 . PMID: 2192379
- [7] Randall C, Randall H, Dobbs F, Hutton C, Sanders H. Randomized controlled trial of nettle sting for treatment of base-of-thumb pain. J R Soc Med (2000) ; 93 : 305-309 . DOI: 10.1177/014107680009300607 . PMID: 10911825
- [8] Chrubasik JE, Roufogalis BD, Wagner H, Chrubasik S. A comprehensive review on the stinging nettle effect and efficacy profiles. Part II: Urticae radix. Phytomedicine (2007) ; 14 : 568-579 . DOI: 10.1016/j.phymed.2007.03.014 . PMID: 17509841
- [9] Roschek B Jr, Fink RC, McMichael M, Alberte RS. Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis. Phytother Res (2009) ; 23 : 920-926 . DOI: 10.1002/ptr.2763 . PMID: 19140159
- [10] Riehemann K, Behnke B, Schulze-Osthoff K. Plant extracts from stinging nettle (Urtica dioica), an antirheumatic remedy, inhibit the proinflammatory transcription factor NF-kappaB. FEBS Lett (1999) ; 442 : 89-94 . DOI: 10.1016/S0014-5793(98)01622-6 . PMID: 9923611
Traditional Texts
- [11] Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine. Healing Arts Press, Rochester, VT (2003)
- [12] Bone K, Mills S. Principles and Practice of Phytotherapy: Modern Herbal Medicine (2nd edition). Churchill Livingstone/Elsevier (2013)
Pharmacopeias & Reviews
- [13] European Pharmacopoeia Commission. European Pharmacopoeia Monograph: Urticae folium (Nettle Leaf) and Urticae radix (Nettle Root). European Pharmacopoeia, Council of Europe, Strasbourg (2020)
- [14] Blumenthal M, Goldberg A, Brinckmann J. Herbal Medicine: Expanded Commission E Monographs. Integrative Medicine Communications, Newton, MA (2000)
Last updated: 2026-02-26 | Status: review