NutriDex

The Supplement Research Compendium
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Stinging Nettle

Urtica dioica

Root for prostate symptoms; leaf studied for joints and blood sugar.

Moderate evidence ✨Joint & Skin⚡Performance

✚ Updated · How we grade evidence

Evidence tier
Moderate
Research weight
Citations
8 verified / 8
Classification
Joint & Skin
❝
What the evidence says. Graded moderate: several double-blind RCTs and a meta-analysis show real but modest benefit of root extract for BPH urinary symptoms, and small diabetes trials plus a meta-analysis show lower fasting glucose and HbA1c. Most trials are small, short, single-country (largely Iranian) and not independently replicated, so confidence is limited. (Moderate evidence: Several controlled trials; effects real but modest or context-dependent.)

What is Stinging Nettle?

Stinging Nettle (Urtica dioica) is a joint and skin supplement used for ease bph urinary symptoms. NutriDex grades the human evidence as Moderate. Stinging nettle is used in two distinct ways: the root for benign prostatic hyperplasia (BPH) and the leaf for blood sugar, allergies and joint pain. The best evidence is for root extract in BPH: a 6-month double-blind RCT in 620 men cut symptom scores from ~19.8 to 11.8 (vs little change on placebo), and a meta-analysis of 5 trials (~1,128 men) found improved symptom scores and urinary flow without affecting PSA. In type 2 diabetes, small RCTs and a meta-analysis report lower fasting glucose (about -17 mg/dL) and HbA1c (about -0.9%), usually added to standard drugs. Topical nettle 'sting' modestly reduced thumb-joint osteoarthritis pain in a small crossover trial. Allergic-rhinitis results are weak, with placebo improving similarly. Trials are mostly small, short and concentrated in a few centres, so effects are promising but not definitive.

Purported Benefits

✓Ease BPH urinary symptoms
✓Lower blood sugar (adjunct)
✓Relieve joint pain (topical)
✓Hay-fever symptom support

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Ease BPH urinary symptomsRoot extract cut IPSS in a 620-man RCT and a 5-trial meta-analysis; centers are few and PSA unchanged. Moderate ↑ benefit · moderate 3
Lower blood glucose / HbA1cMeta-analysis shows lower fasting glucose and HbA1c, but as an add-on to standard drugs in small trials. Moderate ↑ benefit · small 2
Relieve joint pain (topical)One small (n=27) crossover trial of topical sting reduced thumb-base OA pain. Preliminary ↑ benefit · moderate 1
Allergic rhinitis / hay feverSmall RCT improved symptoms but placebo improved similarly, so net benefit is unclear. Mixed — no effect · negligible 1

Dosing & Compounds

Typical Dose
Root extract ~300–600 mg/day (or 600–1200 mg dried root) for prostate symptoms; leaf extract ~500 mg three times daily studied for blood sugar.
Active Compounds
Lignans & polysaccharides (root)Sterols (beta-sitosterol)Flavonoids & chlorogenic acidHistamine/serotonin (leaf hairs)

Safety & Cautions

Oral root and leaf extracts are generally well tolerated; the main side effects are mild GI upset, headache, nausea and occasional fluid changes (nettle is a mild diuretic). Because nettle can lower blood glucose and blood pressure, it may add to antidiabetic drugs (risk of hypoglycemia) and antihypertensives; its vitamin K content and diuretic action could affect warfarin and lithium handling, so monitor if you take these. Fresh leaf contact causes a transient stinging rash, and use in pregnancy/breastfeeding is not established and best avoided. Men should not self-treat prostate symptoms with nettle without ruling out cancer first. Educational only — always check with your doctor or pharmacist before combining Stinging Nettle with any medicine.

Stinging Nettle drug interactions

Known or theoretical interactions between Stinging Nettle and common medications — educational, not exhaustive. Always check with your doctor or pharmacist before combining Stinging Nettle with any medicine.

Caution
Blood thinners (warfarin, DOACs)
Nettle is high in vitamin K and may REDUCE warfarin's effect; keep intake consistent and monitor INR.
Vitamin K antagonizes warfarin by restoring vitamin K-dependent clotting factors, lowering anticoagulation. NIH ODS — Vitamin K (warfarin interaction) · NCCIH — Stinging Nettle (BPH digest)

Key Studies

Meta-analysis Tabrizi 2020 ✓ Full text
Meta-analysis (13 trials): nettle lowered fasting glucose (WMD -17.2 mg/dL) and HbA1c (WMD -0.93%) vs control.
Meta-analysis Men 2016 ✓ Full text
Meta-analysis of 5 RCTs (~1,128 men): Urtica dioica improved IPSS and peak urinary flow (Qmax) vs control, with no effect on PSA.
Safety LiverTox 2023 ✓ Full text
NIH review: stinging nettle is an unlikely cause of liver injury (score E); reported side effects are mild GI upset, headache, nausea.
RCT Bakhshaee 2017 ✓ PubMed
RCT in allergic rhinitis (n=74; 40 completed): nettle improved symptoms and cut nasal eosinophils, but placebo improved similarly.
RCT Ghorbanibirgani 2013 ✓ PubMed
Randomized double-blind trial (n=100 BPH): nettle herb reduced lower-urinary-tract symptoms vs placebo over the study period.
RCT Kianbakht 2013 ✓ PubMed
RCT in advanced T2DM (n=92, 1,500 mg/day leaf extract, 3 mo): significantly lower HbA1c vs placebo as add-on to standard drugs.
RCT Safarinejad 2005 ✓ PubMed
6-mo double-blind RCT (n=620 BPH): IPSS fell 19.8→11.8 on nettle vs 19.2→17.7 placebo; 81% vs 16% improved; PSA unchanged.
RCT Randall 2000 ✓ PubMed
Double-blind crossover RCT (n=27): topical nettle sting cut thumb-base osteoarthritis pain and disability vs placebo (P=0.026; P=0.0027).
8 sources cited · 8 verified Search all studies on PubMed ↗

Common questions about Stinging Nettle

What is Stinging Nettle used for?

Stinging Nettle is most often taken for Ease BPH urinary symptoms, Lower blood sugar (adjunct), Relieve joint pain (topical), Hay-fever symptom support. Root for prostate symptoms; leaf studied for joints and blood sugar.

Does Stinging Nettle work — what does the evidence say?

Moderate evidence. Several controlled trials; effects real but modest or context-dependent. Stinging nettle is used in two distinct ways: the root for benign prostatic hyperplasia (BPH) and the leaf for blood sugar, allergies and joint pain. The best evidence is for root extract in BPH: a 6-month double-blind RCT in 620 men cut symptom scores from ~19.8 to 11.8 (vs little change on placebo), and a meta-analysis of 5 trials (~1,128 men) found improved symptom scores and urinary flow without affecting PSA. In type 2 diabetes, small RCTs and a meta-analysis report lower fasting glucose (about -17 mg/dL) and HbA1c (about -0.9%), usually added to standard drugs. Topical nettle 'sting' modestly reduced thumb-joint osteoarthritis pain in a small crossover trial. Allergic-rhinitis results are weak, with placebo improving similarly. Trials are mostly small, short and concentrated in a few centres, so effects are promising but not definitive.

What is the typical dose of Stinging Nettle?

Root extract ~300–600 mg/day (or 600–1200 mg dried root) for prostate symptoms; leaf extract ~500 mg three times daily studied for blood sugar.

Is Stinging Nettle safe? Any cautions or side effects?

Oral root and leaf extracts are generally well tolerated; the main side effects are mild GI upset, headache, nausea and occasional fluid changes (nettle is a mild diuretic). Because nettle can lower blood glucose and blood pressure, it may add to antidiabetic drugs (risk of hypoglycemia) and antihypertensives; its vitamin K content and diuretic action could affect warfarin and lithium handling, so monitor if you take these. Fresh leaf contact causes a transient stinging rash, and use in pregnancy/breastfeeding is not established and best avoided. Men should not self-treat prostate symptoms with nettle without ruling out cancer first.

How many studies support Stinging Nettle?

NutriDex cites 8 sources for Stinging Nettle, graded "Moderate".

Does Stinging Nettle interact with any medications?

Yes — known or theoretical interactions include: Blood thinners (warfarin, DOACs) (caution). This is educational and not exhaustive; always check with your doctor or pharmacist before combining Stinging Nettle with any medicine.

Cite this page
APA

Peh, D. (2026). Stinging Nettle (Urtica dioica): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/nettle

BibTeX
@misc{nutridex_nettle,
  author       = {Peh, Daryl},
  title        = {Stinging Nettle (Urtica dioica): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/nettle},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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