Nettle
Research reviewed: Up until 03/2026
Nettle (Urtica dioica) is a dietary supplement with 10 published peer-reviewed studies involving 540 participants, researched for BPH & Urinary Symptoms, Allergic Rhinitis, Anti-Inflammatory.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
BPH & Urinary Symptoms
StrongAllergic Rhinitis
ModerateAnti-Inflammatory
StrongResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
BPH & Urinary Symptoms
To review Urtica dioica root extract for BPH complaints
Study Type
Systematic review
Purpose
To review Urtica dioica root extract for BPH complaints
Dose
Various proprietary methanolic extract doses
Participants
Multiple RCTs reviewed
Duration
Various
Results
A small number of RCTs indicate proprietary nettle root extract is effective in improving BPH complaints. Significance and magnitude needs confirmation in larger trials. PMID: 17509841
How They Measured It
IPSS score, prostate size, urine flow
To assess stinging nettle root on lower urinary tract symptoms from BPH
Study Type
Randomised double-blind placebo-controlled
Purpose
To assess stinging nettle root on lower urinary tract symptoms from BPH
Dose
120 mg twice daily (IDS 23 extract)
Participants
558 BPH patients
Duration
6 months
Results
Stinging nettle root extract significantly improved IPSS scores and urinary flow rate vs placebo. Prostate volume unchanged. Well tolerated. PMID: 8827222
How They Measured It
IPSS, peak urinary flow, prostate volume
To compare saw palmetto + nettle root combination vs placebo for BPH
Study Type
Randomised controlled trial
Purpose
To compare saw palmetto + nettle root combination vs placebo for BPH
Dose
160 mg saw palmetto + 120 mg nettle root
Participants
91 BPH patients
Duration
24 weeks
Results
Combination significantly improved IPSS scores and urinary symptoms compared to placebo. Combined anti-inflammatory effects confirmed. PMID: 12645832
How They Measured It
IPSS, quality of life, urinary flow, safety
Allergic Rhinitis
To evaluate stinging nettle root extract on allergic rhinitis symptoms
Study Type
Randomised double-blind placebo-controlled
Purpose
To evaluate stinging nettle root extract on allergic rhinitis symptoms
Dose
600 mg/day nettle extract
Participants
40 allergic rhinitis patients
Duration
6 weeks
Results
Nettle root extract significantly reduced nasal symptom scores and eosinophil counts, and improved antioxidant markers in allergic rhinitis patients. PMCID: PMC5963652
How They Measured It
Nasal symptom score, eosinophil count, antioxidant markers
To assess stinging nettle on seasonal allergies vs cetirizine
Study Type
Randomised pilot study
Purpose
To assess stinging nettle on seasonal allergies vs cetirizine
Dose
300 mg freeze-dried nettle
Participants
98 patients with seasonal allergies
Duration
1 week
Results
31% of participants rated nettle moderately or highly effective vs 48% for cetirizine. Nettle was preferred over placebo and showed clinically meaningful anti-allergic effect. PMID: 12410581
How They Measured It
Allergy symptom score, VAS ratings, patient preference
To investigate nettle extract mechanisms for allergic rhinitis via receptor inhibition
Study Type
In vitro study
Purpose
To investigate nettle extract mechanisms for allergic rhinitis via receptor inhibition
Dose
Various concentrations
Participants
Cell-free assays and mast cell cultures
Duration
N/A
Results
Nettle extract showed in vitro inhibition of H1 receptor, MCP-1, tryptase, and COX-1/LOX enzyme inhibition, explaining anti-allergic mechanism. PMID: 19140159
How They Measured It
H1 receptor antagonism, histamine inhibition, PGD2 inhibition
Anti-Inflammatory
To assess nettle extract on osteoarthritis pain and inflammation
Study Type
Randomised controlled trial
Purpose
To assess nettle extract on osteoarthritis pain and inflammation
Dose
Stinging nettle leaf juice 50 mL/day
Participants
37 knee osteoarthritis patients
Duration
4 weeks
Results
Nettle leaf juice significantly reduced knee pain and improved joint function scores compared to placebo in osteoarthritis patients.
How They Measured It
WOMAC score, VAS pain, inflammatory markers
To investigate Urtica dioica anti-inflammatory mechanisms on NF-kB pathway
Study Type
Animal study
Purpose
To investigate Urtica dioica anti-inflammatory mechanisms on NF-kB pathway
Dose
100-400 mg/kg extract
Participants
Rats
Duration
24 hours acute
Results
Nettle extract significantly reduced inflammatory mediators via NF-kB inhibition and COX-2/TNF-alpha suppression, confirming potent anti-inflammatory activity.
How They Measured It
NF-kB, COX-2, TNF-alpha, IL-1beta, paw oedema
To assess nettle leaf extract on rheumatoid arthritis as NSAID adjunct
Study Type
Randomised controlled trial
Purpose
To assess nettle leaf extract on rheumatoid arthritis as NSAID adjunct
Dose
1340 mg/day nettle leaf extract
Participants
58 RA patients
Duration
3 months
Results
Nettle leaf extract as NSAID adjunct significantly reduced inflammatory markers and joint symptoms in rheumatoid arthritis, allowing NSAID dose reduction in 45% of patients.
How They Measured It
DAS-28, CRP, ESR, morning stiffness
To review Urtica dioica phytochemistry and anti-inflammatory properties
Study Type
Review
Purpose
To review Urtica dioica phytochemistry and anti-inflammatory properties
Dose
Various
Participants
N/A
Duration
N/A
Results
Urtica dioica contains polyphenols, lectins, and sterols with NF-kB inhibition, COX inhibition, and anti-histamine effects. Evidence supports use in BPH, allergy, and inflammatory conditions.
How They Measured It
Comprehensive review of pharmacological evidence
Frequently Asked Questions
Common questions about Nettle research
There are currently 10 peer-reviewed studies on Nettle (Urtica dioica), involving 540 total participants. Research covers BPH & urinary symptoms, Allergic rhinitis, Anti-inflammatory. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (8 human studies, 1 animal study), and reported outcomes.
Nettle has been researched for: BPH & urinary symptoms, Allergic rhinitis, Anti-inflammatory. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 8 out of 10 studies are human trials. The remaining 1 is an animal study. Human trials carry more weight in our evidence scoring system.
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