← Folk Protocol

Stinging Nettle

Urtica dioica

Also known as: common nettle, nettle, stinging nettle, urtica

One of Europe's most thoroughly codified medicinal plants, with distinct evidence for the root (BPH) and leaf (blood sugar, diuresis, joint support). Unusually clean safety record — no documented liver toxicity across all major surveillance databases.

Traditional Use

Traditions: European herbalism, Ayurveda, TCM, North American folk

Historical Attributions

Urtica dioica leaf used since Greco-Roman antiquity for urinary gravel, diuresis, joint pain (via intentional stinging), and as a spring tonic. Pliny the Elder documented urtication for arthritic joints in the 1st century AD. Culpeper (17th c.) recommended it for kidney stones. German naturopathic tradition adopted the root for prostate complaints in the early 20th century, codified by Commission E in 1987.

Known as Bichhu buti; classified with dry (ruksha) and hot (ushna) properties. Used as a diuretic, for skin diseases, hemorrhagic conditions, and urinary stones. Less central than in European traditions; more prominent in regional Indian folk practice.

Xun ma (荨麻); used to expel wind-dampness, relieve pain, reduce swelling. Applied for rheumatic pain and as a diuretic. Regional/folk use rather than classical canon.

Evidence

Root and leaf carry separate, substantiated evidence profiles. Root for BPH: two meta-analyses including 1,128–1,210 participants, consistently large effect sizes, endorsed by Commission E (1987), EMA, and Health Canada. Leaf for type 2 diabetes: two meta-analyses (13 RCTs combined) showing clinically meaningful reductions in fasting glucose (-17 mg/dL) and HbA1c (-0.93%). Leaf for joint support and urinary irrigation: traditionally codified (Commission E 1990) with preliminary clinical support. Allergic rhinitis: two small RCTs, insufficient for clinical recommendation. Exceptionally clean safety record across all indications.

Key Studies

• Men et al. 2016 — BPH Meta-Analysis (2016)

  5 RCTs, 1,128 participants. IPSS score: SMD -10.47 (p=0.007). Peak urinary flow and prostate volume also improved vs placebo across studies. No adverse events across all 5 studies.

• Safarinejad 2005 — BPH RCT (2005)

  558 participants, 6 months, randomized double-blind. IPSS: 19.8 → 11.8 (treatment) vs 19.2 → 17.7 (placebo). 81% treatment responders vs 16% placebo. Max flow rate +8.2 vs +3.4 mL/s. Post-void residual halved.

• Tabrizi et al. 2022 — T2DM Meta-Analysis (2022)

  13 RCTs. Fasting blood glucose: -17 mg/dL. HbA1c: -0.93%. CRP: -1.09 mg/dL. Triglycerides: -27 mg/dL. Systolic BP: -5 mmHg. All statistically significant.

• Kianbakht et al. 2013 — T2DM RCT (2013)

  92 participants with advanced T2DM on insulin. 1,500 mg/day nettle leaf extract for 3 months. Fasting glucose reduced (p<0.001), postprandial glucose reduced (p=0.009), HbA1c reduced (p=0.006) vs placebo. No hepatic or renal adverse effects.

Preparations

tea — 2–4 g dried leaf per cup, 3× daily (6–12 g/day total)

Taste: Mild, grassy, slightly mineral and vegetal. Not unpleasant. Warming.

Steep 5–10 minutes. Commission E approved for urinary irrigation; increase fluid intake to at least 2 L/day for this use. Mild grassy, slightly astringent taste — one of the more palatable medicinal teas.

extract — Leaf: 536 mg (8–10:1, 50% ethanol extract) 1–2× daily. Root: 450 mg/day or 360 mg/day (aqueous) to 600–1,200 mg/day (methanolic). For T2DM: 500 mg leaf extract 3× daily.

Part matters: root extract for BPH, leaf extract for glycemic and urinary support. Most commercial capsules don't specify extraction method or standardization marker — look for those that do.

tincture — 1:5, 45% ethanol: 2–6 mL, 3× daily

Leaf tincture for urinary and arthritic support. Root tincture less commonly used; standardized extracts preferred for BPH.

decoction — 1.5–2 g dried root, simmered 10–15 min, 3× daily (4.5–6 g/day total)

Traditional preparation for root (BPH). Commission E approved. Lower-cost alternative to capsules but dose consistency is harder to control.

fresh — Applied directly to affected joint (urtication)

Intentional stinging of painful joints. Counter-irritant effect; transient urticarial rash and burning expected, resolves within hours. Pilot study only (n=18); no RCT confirmation. Traditional practice from antiquity.

What The Evidence Says

Stinging nettle has a split personality in the evidence base: the root and the leaf are different medicines with different research behind them.

Root — BPH (strong evidence):

• Two meta-analyses totaling 1,128–1,210 participants consistently favor nettle root over placebo for urinary symptoms [1][5]
• In the largest single RCT (Safarinejad 2005, n=558, 6 months), IPSS urinary symptom scores fell from 19.8 to 11.8 on nettle vs. 19.2 to 17.7 on placebo — and 81% of nettle patients reported improvement vs. 16% placebo [2]
• German Commission E approved the root for BPH stages I and II in 1987; Health Canada similarly licenses it for lower urinary tract symptoms [6]. These are formal regulatory endorsements, not just positive trials.
• Not a cure — it doesn’t shrink the prostate dramatically, and it works best for moderate, not severe symptoms

Leaf — type 2 diabetes (moderate evidence):

• A 2022 meta-analysis of 13 RCTs found nettle leaf reduces fasting blood glucose by ~17 mg/dL, HbA1c by 0.93 percentage points, triglycerides by 27 mg/dL, and CRP by 1 mg/dL — all statistically significant [3]
• In a 3-month RCT with 92 advanced T2DM patients on insulin, 1,500 mg/day leaf extract improved fasting glucose, postprandial glucose, and HbA1c compared to placebo — with no adverse effects on liver or kidneys [4]
• This is adjunctive evidence, not a replacement for standard diabetes care

Leaf — joint and urinary support (traditional endorsement):

• Commission E (1990) approved nettle leaf for urinary irrigation and rheumatic complaints [6]. EMA similarly recognized it for mild arthritis and urinary symptoms based on 30+ years of traditional use [7].
• Arthritis evidence is preliminary and confounded — the best OA study used a combination product (Phytalgic), making nettle’s individual contribution unclear [9]
• Allergic rhinitis: two small RCTs with mixed results [10][11] — not enough to recommend as primary treatment

What’s unusual here is the safety record: LiverTox rates nettle at Score E — no documented cases of liver injury in any major surveillance database, across all indications [8]. In herbal medicine, this is genuinely rare.

Traditional Use

European herbalism (2,000+ years):

• Urtica dioica leaf appears in Greek and Roman medicine for urinary gravel, diuresis, and wound treatment
• Pliny the Elder documented urtication — deliberately pressing fresh nettle against arthritic joints — in the 1st century AD. This practice survived in rural Britain and Germany into the 20th century.
• Nicholas Culpeper (17th c.) recommended it for “expelling gravel and stone from the reins and bladder” — essentially the same diuretic/urinary indication codified by Commission E 300 years later
• The root’s prostate use emerged in German naturopathic practice in the early 20th century, well before clinical trials

Nutritional medicine:

• Nettle leaf has been eaten across Northern Europe as a spring food — boiled or steamed to remove sting. High in iron, calcium, potassium, and vitamins A and K.
• Traditional use for anemia and fatigue reflects real nutritional content. “Nettle soup” and nettle beer are documented folk foods, not just herbal medicine.

Regulatory codification tells the story of convergence: Commission E (Germany’s formal herb review body) endorsed both the leaf (1990) and root (1987) — a formal recognition that this plant’s traditional uses met their evidence standard for safety and plausibility [6]. EMA followed in 2011 [7]. These aren’t endorsements of efficacy, but they’re not nothing.

TCM and Ayurveda both use nettle, though less prominently — mostly for joint pain, diuresis, and urinary complaints, consistent with the European tradition.

How To Try It

Part first — root or leaf?

Goal	Part	Form
BPH / urinary symptoms in men	Root	Capsule (extract) or decoction
Blood sugar support (T2DM adjunct)	Leaf	Capsule (extract)
Urinary irrigation / kidney gravel	Leaf	Tea (with lots of water)
Joint support (mild arthritis)	Leaf	Tea or extract
Nutritional (iron, vitamins)	Leaf	Tea or fresh/cooked

Leaf tea (most accessible)

Pour boiling water over 2–4 g dried leaf (roughly 1–2 teaspoons), steep 5–10 minutes, strain. Drink 3 cups daily. Nettle tea is one of the more pleasant medicinal teas — mild, grassy, slightly mineral. For urinary irrigation, drink at least 2 L of additional fluids per day.

Standardized extracts (most consistent with evidence)

Root for BPH:

• Best-characterized clinical dose: 450 mg/day extract (Karami 2020, n=60, 12 weeks) [12]
• Commission E range: 360 mg/day (aqueous) to 600–1,200 mg/day (methanolic) [6]
• Plan for at least 3 months; the 6-month Safarinejad study saw the clearest benefit

Leaf for blood sugar:

• Kianbakht 2013 dose: 500 mg leaf extract, 3 times daily = 1,500 mg/day
• Take with meals (reduces GI upset and matches study protocol)

Tincture (leaf): 2–6 mL, 1:5 in 45% ethanol, 3× daily. Good for urinary and arthritic support.

Root decoction (budget-friendly BPH option)

Simmer 1.5–2 g dried root in water for 10–15 minutes, strain. Drink 3× daily (4.5–6 g root total). Less predictable than standardized extracts but Commission E approved.

What To Track

Baseline before starting:

• For BPH: night-time urination frequency, stream strength, sense of incomplete emptying (IPSS questionnaire is freely available and useful)
• For blood sugar: fasting glucose readings, HbA1c at next lab draw
• For joints: morning stiffness duration, pain medication use, ease of specific movements

During trial:

• BPH: check IPSS at 6 weeks and 3 months. Meaningful improvement should be visible by week 8–12 if it’s going to work.
• Blood sugar: fasting glucose weekly if monitoring at home; HbA1c needs 8–12 weeks to move meaningfully
• Urinary irrigation: urine clarity, comfort, frequency — effects apparent within 1–2 weeks

If on medications — watch closely:

• On insulin or oral hypoglycemics: monitor blood glucose more frequently when starting nettle leaf. The 17 mg/dL fasting glucose reduction is clinically meaningful and can add to medication effects [3].
• On diuretics: watch for excessive fluid loss or electrolyte shifts
• On warfarin: use standardized extract (not whole leaf), and monitor INR — fresh nettle leaf is high in vitamin K

Stop if:

• GI upset doesn’t resolve after 1 week with food
• Any signs of allergic reaction
• Edema worsens (do not use for cardiac- or renal-origin edema)

Who This Is/Isn’t For

Most likely to benefit:

• Men with moderate BPH (stages I–II, IPSS 8–19) not yet on medication or wanting to reduce symptom burden before considering drugs
• People with T2DM seeking adjunctive glycemic support alongside conventional treatment
• Those using it nutritionally — nettle leaf is genuinely nutrient-dense and safe long-term as a food/tea
• Anyone with mild arthritis looking for supportive botanical therapy alongside other management

Non-responders (limited benefit expected):

• BPH stage III+ with significant obstruction — evidence is for mild-to-moderate symptoms; medical management needed
• T2DM with poorly controlled glucose — nettle is adjunctive, not primary treatment
• Allergic rhinitis — evidence is too thin to recommend as a primary therapy; other options have stronger trials

Clear contraindications:

• Pregnancy — traditional emmenagogue use and uterotonic risk; contraindicated per Commission E, EMA, and Health Canada
• Breastfeeding — insufficient safety data (despite folk galactagogue use, not recommended)
• Cardiac or renal edema — do not use leaf for diuretic purposes; can worsen fluid balance
• Known Urticaceae allergy

The Sting

The sting is worth understanding. Fresh nettle has microscopic silica needles (trichomes) loaded with formic acid, histamine, and serotonin — that’s what causes the burning weal when you brush against it. This is destroyed by drying, heating, or extraction. Dried leaf tea, capsules, and tinctures don’t sting.

The traditional practice of urtication — deliberately pressing fresh nettle against arthritic joints — intentionally uses the sting. The mechanism is probably counter-irritation plus local anti-inflammatory effects. A small uncontrolled pilot (n=18) found it helpful for joint pain; no serious adverse effects [13]. No RCT yet. If you try it, the rash is transient (hours) and expected.

Quality Matters

Nettle has a simpler quality situation than most herbs — it’s not heavily adulterated and doesn’t accumulate heavy metals the way some plants do. But the part and standardization are the main variables:

What to look for:

• Clear labeling of root vs. leaf — these are different products with different uses
• Extraction method noted (aqueous, methanolic, or hydroalcoholic) — affects which compounds are concentrated
• For root: Commission E aqueous dose is 360 mg/day; methanolic range is 600–1,200 mg/day. Most commercial capsules are in the 300–500 mg range — check if aqueous or methanolic
• For leaf: no single harmonized marker compound exists; look for brands that specify chlorogenic acid, rutin, or “flavonoid” content analytically
• Third-party testing for heavy metals and identity if buying bulk herb

No single “gold standard” extract brand exists for nettle the way KSM-66/Sensoril do for ashwagandha. Clinical trials used various extracts without standardized markers — this is a genuine gap. Focus on sourcing from established supplement companies that publish third-party test results.

Organic sourcing reduces pesticide exposure; nettle grows prolifically as a weed and organic certification is common and affordable.

The Bottom Line

Nettle root for BPH is among the better-evidenced botanical options available — two meta-analyses, regulatory endorsement from Commission E, EMA, and Health Canada, and an unusually clean safety record. If you have mild-to-moderate urinary symptoms from BPH and want a botanical before or alongside conventional approaches, this is a reasonable choice. Give it 3–6 months.

Nettle leaf for blood sugar is genuinely interesting — 13 RCTs, clinically meaningful reductions in glucose, HbA1c, and triglycerides. The catch: this is adjunctive evidence for people already on conventional diabetes care, not a replacement. If you’re managing T2DM and want additional nutritional support, nettle leaf (1,500 mg/day) is worth discussing with whoever manages your medications, especially if you’re on insulin.

For joint support, diuresis, and urinary complaints: substantial traditional use, regulatory codification, and enough preliminary clinical evidence to consider it reasonable. Not dramatic, not transformative — supportive.

The biggest thing working in nettle’s favor, across all indications, is how boring its safety profile is. No liver cases. No serious adverse events in controlled trials. After 2,000 years of use and multiple modern RCTs, that’s meaningful.

[1] Men et al. 2016 — Urtica dioica for BPH meta-analysis (5 RCTs, n=1,128; PMID 27196048) [2] Safarinejad 2005 — Randomized double-blind BPH RCT (n=558) [3] Tabrizi et al. 2022 — Nettle leaf T2DM meta-analysis (13 RCTs) [4] Kianbakht et al. 2013 — Nettle leaf in advanced T2DM on insulin (n=92) [5] 2025 Systematic Review — Urtica dioica in BPH (6 RCTs, n=1,210) [6] German Commission E Monographs — Nettle Root (1987) and Leaf (1990) [7] EMA/HMPC Assessment Report on Urtica dioica (2011) [8] LiverTox — Stinging Nettle Hepatotoxicity Assessment (NIH/NCBI NBK589898) [9] Jacquet et al. 2009 — Phytalgic OA RCT (PMID 20015358) [10] Mittman 1990 — Freeze-dried nettle for allergic rhinitis (PMID 2192379) [11] Bakhshaee et al. 2017 — Nettle for allergic rhinitis (PMID 29844782) [12] Karami et al. 2020 — Nettle root extract 450 mg/day BPH RCT [13] Chrubasik et al. 2007 — Active compounds and mechanisms review (PMID 17568474)

Trying It

Duration: Root for BPH: minimum 3 months; Safarinejad 2005 used 6 months for full assessment. Leaf for blood sugar: 8–12 weeks for meaningful HbA1c change. Urinary/diuretic use: 2–4 weeks per episode per EMA guidance.

What to notice:

• For BPH: urinary frequency (especially at night), force of stream, sense of incomplete emptying
• For blood sugar: fasting glucose readings (measurable changes in 4–8 weeks)
• For urinary irrigation: urine output, clarity, reduction in discomfort
• For joint support: morning stiffness, ease of movement, need for pain medication
• GI comfort (take with food if any upset occurs)

Root and leaf are distinct preparations with different targets — make sure you have the right part for your goal. Start with tea if you're new to nettle (affordable, easy to adjust). For BPH support, standardized root extract capsules are most consistent with clinical trial doses. For blood sugar, the best-characterized dose is 500 mg leaf extract 3× daily with meals (Kianbakht 2013). Do not use leaf as primary treatment for blood sugar — this is adjunctive alongside conventional care, and you need to monitor glucose if on insulin or oral hypoglycemics.

Combinations

• saw palmetto — Most studied BPH combination. Complementary mechanisms — saw palmetto primarily 5-alpha reductase, nettle root primarily SHBG/aromatase. Common in commercial BPH formulas.
• pygeum — Standard European BPH combination; additive symptomatic benefit. Commission E approves both independently.
• dandelion — Complementary diuretics for urinary irrigation and kidney gravel support. Both Commission E recognized for this use.
• turmeric — Complementary anti-inflammatory pairing for joint and metabolic support; both have CRP-lowering evidence.

Safety

Generally considered: safe

Contraindications:

• Pregnancy — traditional emmenagogue use and insufficient safety data; contraindicated per Commission E, EMA, and Health Canada
• Breastfeeding — insufficient safety data; not recommended despite folk use as galactagogue
• Edema from cardiac or renal insufficiency — contraindicated for leaf irrigation therapy (diuretic use may worsen fluid imbalance)
• Known allergy to Urtica or Urticaceae family plants

Pregnancy/Nursing: Contraindicated in pregnancy (emmenagogue tradition, theoretical uterotonic risk, no safety data). Not recommended during breastfeeding despite historical folk use as milk-promoter — insufficient evidence.

LiverTox Score E (no documented cases of liver injury from nettle root or leaf in any major surveillance database). No serious adverse events in any controlled trials. Most common complaint is mild GI upset — take with food. Drug interactions to watch: if on diuretics (additive effect), antidiabetics or insulin (additive blood glucose lowering — monitor closely), or warfarin (high-dose whole leaf contains vitamin K — use standardized extracts and monitor INR). Antihypertensives: modest additive SBP lowering (-5 mmHg) at clinical doses. Contact sting from fresh plant is expected, not dangerous — resolves within hours.

Sources

• Men et al. 2016 — Urtica dioica for BPH Meta-Analysis meta-analysis (2016)
• 2025 Systematic Review of Urtica dioica in BPH (6 RCTs, n=1,210) meta-analysis (2025)
• Safarinejad 2005 — Randomized Double-Blind BPH RCT (n=558) study (2005)
• Karami et al. 2020 — Nettle Root Extract 450 mg/day, BPH RCT study (2020)
• Tabrizi et al. 2022 — Nettle Leaf for T2DM Meta-Analysis (13 RCTs) meta-analysis (2022)
• Ziaei et al. 2020 — Nettle Leaf for T2DM Meta-Analysis (8 RCTs) meta-analysis (2020)
• Kianbakht et al. 2013 — Nettle Leaf in Advanced T2DM (n=92) study (2013)
• Chrubasik et al. 2007 — Active Compounds and Mechanisms Review study (2007)
• Bonetti et al. 2016 — Bioavailability Study (PMID 27713992) study (2016)
• LiverTox — Stinging Nettle Hepatotoxicity Assessment (NBK589898) other
• German Commission E Monograph — Nettle Leaf (1990) and Root (1987) traditional-text
• EMA/HMPC Assessment Report on Urtica dioica (2011) traditional-text
• Mittman 1990 — Freeze-Dried Nettle for Allergic Rhinitis (PMID 2192379) study (1990)
• Bakhshaee et al. 2017 — Nettle Root for Allergic Rhinitis (PMID 29844782) study (2017)
• Jacquet et al. 2009 — Phytalgic OA RCT (PMID 20015358) study (2009)