Stinging nettle
Two trials of nettle root in men with an enlarged prostate report lower symptom scores than placebo, the larger from a single author who has had another trial retracted. Evidence for nettle leaf in hay fever, joint pain and blood sugar comes from single small trials. Trials reported no side effects.
- Status
- Dietary supplement in the US. Not approved by the FDA as a drug for any use.
- Also called
- Urtica dioica, nettle root, nettle leaf, common nettle, nettle extract, freeze-dried nettle
- Taken for
- prostate health, enlarged prostate, urinary symptoms, allergies, hay fever, joint pain, arthritis, blood sugar
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help3
- LimitedOne small one-week trial found people with hay fever rated nettle higher than placebo overall, and only slightly higher in symptom diaries.
- LimitedOne small trial found nettle leaf applied to painful hand joints lowered pain and disability more than white deadnettle leaf over 1 week.
- LimitedOne trial found lower fasting glucose, post-meal glucose and HbA1c than placebo over 3 months in adults with type 2 diabetes on insulin. Sizes were not given.
Reported risks0
No risks sourced yet.
What people take it for, and what was found
Shown to help3
Hay fever and allergic rhinitis
One small one-week trial found people with hay fever rated nettle higher than placebo overall, and only slightly higher in symptom diaries.
The numbers and sources
Joint pain
One small trial found nettle leaf applied to painful hand joints lowered pain and disability more than white deadnettle leaf over 1 week.
The numbers and sources
- Effect
- In 27 people with osteoarthritis pain at the base of the thumb or index finger, applying stinging nettle leaf to the painful area daily for 1 week reduced pain (p 0.026) and disability (p 0.0027) scores more than white deadnettle leaf [5].
- Population
- 27 adults with hand osteoarthritis [5].
- Sources
- [5]
- Caveats
- One small crossover trial of nettle stings on the skin, not oral nettle.
Blood sugar in type 2 diabetes
One trial found lower fasting glucose, post-meal glucose and HbA1c than placebo over 3 months in adults with type 2 diabetes on insulin. Sizes were not given.
The numbers and sources
- Effect
- In 92 people with advanced type 2 diabetes needing insulin, 500 mg of nettle leaf extract every 8 hours for 3 months, added to their usual drugs, lowered fasting glucose (p less than 0.001), 2-hour post-meal glucose (p 0.009) and HbA1c (p 0.006) against placebo. Creatinine, liver enzymes and blood pressure did not change [6].
- Population
- 92 adults with type 2 diabetes [6].
- Sources
- [6]
- Caveats
- One trial. The abstract gives p-values without the size of the changes.
Mixed results1
Urinary symptoms from an enlarged prostate
Limited evidence: one trial found 81% of men reported better urinary symptoms against 16% on placebo, but its author had another trial retracted. A second trial found an intermediate effect.
The numbers and sources
- Effect
- In 620 men over 6 months, 81% on nettle reported improved urinary symptoms against 16% on placebo. Symptom scores fell from 19.8 to 11.8 on nettle and from 19.2 to 17.7 on placebo, peak flow rose 8.2 mL/s against 3.4 mL/s, and prostate volume fell from 40.1 to 36.3 cc. PSA and testosterone did not change [1]. In 60 men, 450 mg a day of nettle root extract for 12 weeks had what the authors describe as an intermediate effect on symptom scores against placebo [2].
- Population
- Men with benign prostatic hyperplasia [1][2].
- Sources
- [1], [2]
- Caveats
- Trial [1] has a single author, and another trial by the same author has been retracted [3]. Trial [2] reports effect sizes without symptom score changes in its abstract.
Doses studied
One prostate trial used 450 mg a day of root extract for 12 weeks [2]. The diabetes trial used 500 mg of leaf extract three times a day for 3 months [6].
Risks
Checked, no increase found1
Side effects in trials
Small trials found no side effects, and no change in liver enzymes or creatinine.
The numbers and sources
- Effect
- No side effects were identified in either group of the 620-man prostate trial [1] or in the 60-man trial [2]. Liver enzymes and creatinine did not change in the diabetes trial [6].
- Population
- Participants in the trials above [1][2][6].
- Sources
- [1], [2], [6]
- Caveats
- Small trials, and the largest has the reliability concern noted above [3].
Sources
- Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. Journal of Herbal Pharmacotherapy. 2005. https://doi.org/10.1080/J157v05n04_01
- Akbar Karami A, Sheikhsoleimani M, Reza Memarzadeh M, et al. Urtica Dioica Root Extract on Clinical and Biochemical Parameters in Patients with Benign Prostatic Hyperplasia, Randomized Controlled Trial. Pakistan Journal of Biological Sciences. 2020. https://doi.org/10.3923/pjbs.2020.1338.1344
- Safarinejad MR. Retraction Note: Safety and efficacy of dapoxetine in the treatment of premature ejaculation: a double-blind, placebo-controlled, fixed-dose, randomized study. Neuropsychopharmacology. 2023. https://doi.org/10.1038/s41386-023-01550-2
- Mittman P. Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis. Planta Medica. 1990. https://doi.org/10.1055/s-2006-960881
- Randall C, Randall H, Dobbs F, et al. Randomized controlled trial of nettle sting for treatment of base-of-thumb pain. Journal of the Royal Society of Medicine. 2000. https://doi.org/10.1177/014107680009300607
- Kianbakht S, Khalighi-Sigaroodi F, Dabaghian FH. Improved glycemic control in patients with advanced type 2 diabetes mellitus taking Urtica dioica leaf extract: a randomized double-blind placebo-controlled clinical trial. Clinical Laboratory. 2013. https://doi.org/10.7754/clin.lab.2012.121019