Herb

    Nettle Root

    Urtica dioica root

    TL;DR

    Nettle root is a supporting player in benign prostatic hyperplasia, with trials at 300-600 mg/day of extract showing modest improvement in urinary symptoms, usually alongside saw palmetto or pygeum. The popular claim that it frees up testosterone by displacing SHBG binding rests on test-tube data only.

    Ideal For

    • Men with mild to moderate BPH urinary symptoms after clinical assessment
    • Those already taking saw palmetto who want a combination approach
    • Men seeking a well-tolerated adjunct to lifestyle measures

    Avoid If

    • You have not had urinary symptoms medically assessed
    • You are pregnant — nettle root may stimulate uterine activity
    • You take lithium, diuretics or antihypertensives without advice
    • You are buying it primarily to raise free testosterone
    • You take warfarin, given the vitamin K content of some preparations

    Frequently Asked Questions

    Overview

    Urtica dioica root is pharmacologically distinct from the leaf, which is used for allergic rhinitis and joint complaints. The root contains lignans, sterols including beta-sitosterol, polysaccharides and a small lectin called UDA, and its clinical use is confined almost entirely to lower urinary tract symptoms in men.

    The evidence for BPH is genuine but second-tier. Randomised trials of standardised root extract at 300-600 mg/day report reductions in International Prostate Symptom Score, improved peak urinary flow and reduced residual volume over eight to twenty-four weeks. Most of the better trials used it in fixed combination with saw palmetto, which makes attributing the effect to nettle alone difficult. Mechanistically it appears to inhibit 5-alpha-reductase and aromatase weakly, interfere with epidermal growth factor binding on prostate cells, and inhibit sodium-potassium ATPase in prostatic tissue, all of which plausibly slow proliferative growth.

    The claim that draws most buyers — that nettle root lignans bind sex hormone binding globulin and thereby raise free testosterone — comes from in vitro binding assays. No human trial has demonstrated a meaningful rise in free testosterone. Treat that as a marketing story rather than an established effect. Nettle root is well tolerated, with occasional mild gastrointestinal complaints, and its most important caveat is that urinary symptoms in men require a proper diagnosis first: prostate cancer and BPH present similarly.

    How It Works

    • Weakly inhibits 5-alpha-reductase, limiting conversion of testosterone to DHT
    • Weakly inhibits aromatase, reducing local oestrogen in prostatic tissue
    • Lignans bind sex hormone binding globulin in vitro, though human relevance is unproven
    • Interferes with epidermal growth factor receptor binding on prostate epithelial cells
    • Inhibits prostatic sodium-potassium ATPase, slowing cell proliferation
    • Beta-sitosterol contributes anti-inflammatory activity in the prostate

    Quick Facts

    • Reduces SHBG binding
    • Prostate health support
    • Increases free testosterone
    • Anti-inflammatory effects
    • Supports urinary function

    Benefits & Outcomes

    Free Testosterone Increase

    Hormonal
    Insufficient evidence
    Moderate Evidence

    The SHBG-binding hypothesis is popular but has not been demonstrated to raise free testosterone in humans.

    Prostate Size Reduction

    Mens Health
    Insufficient evidence
    Moderate Evidence

    Symptom improvement is better documented than any actual reduction in prostate volume.

    Health Concerns Addressed

    BPH (Benign Prostatic Hyperplasia)

    condition
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    Nettle root may modestly improve urinary symptoms in benign prostatic hyperplasia, but trials are limited.

    Supporting Research
    6 studies

    Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study

    Score: 7/10
    2005
    crossover
    n=620

    Safarinejad MR

    Nettle root improved IPSS scores and peak urinary flow versus placebo without changing prostate size or PSA.

    View source

    Efficacy and safety of a combination of sabal and urtica extract in lower urinary tract symptoms: a randomized, double-blind study versus tamsulosin

    Score: 6/10
    2006
    rct
    n=140

    Engelmann U, Walther C, Bondarenko B

    A saw palmetto plus nettle root combination was non-inferior to tamsulosin for IPSS improvement with fewer adverse effects.

    View source

    The efficacy of stinging nettle (Urtica dioica) in patients with benign prostatic hyperplasia: a randomized double-blind study in 100 patients

    Score: 5/10
    2013
    rct
    n=100

    Ghorbanibirgani A, Khalili A, Zamani L

    Nettle extract for six months reduced IPSS scores and serum PSA compared with placebo.

    View source

    The effect of nettle root extract on urinary problems in older men with benign prostatic hyperplasia: a randomized clinical trial

    Score: 5/10
    2022
    rct
    n=100

    Khalafi-Kheydani A, Mahmoodi H, Sadat Z +1 more

    Nettle root extract improved urinary symptom scores and nocturia in older men.

    View source

    Serenoa repens for benign prostatic hyperplasia

    Score: 9/10
    2012
    meta_analysis
    n=5666

    Tacklind J, Macdonald R, Rutks I +2 more

    Higher-quality trials of plant-based BPH therapies show no benefit over placebo for urinary symptoms or flow rate.

    View source

    Urtica dioica: a review of its phytochemistry, pharmacology and clinical use

    Score: 5/10
    2022
    systematic_review

    Bhusal KK, Magar SK, Thapa R

    Nettle root lignans inhibit sex hormone-binding globulin binding and 5-alpha-reductase in vitro.

    View source

    Safety Information

    Potential Side Effects

    Generally safe. May cause mild allergic reactions in those sensitive to nettles. Can interact with blood thinners and blood pressure medications. Typical dose 300-600mg root extract daily.

    Contraindications

    Pregnancy, and undiagnosed lower urinary tract symptoms. Use caution with lithium, diuretics, antihypertensives and anticoagulants.

    Drug Interactions

    • Lithium — reduced clearance from diuretic effect
    • Antihypertensives — additive blood pressure lowering
    • Diuretics — additive fluid and electrolyte loss
    • Warfarin — vitamin K content in some preparations may reduce INR
    • Diabetes medication — possible additive glucose lowering

    Pregnancy & Breastfeeding

    Pregnancy: likely_unsafe

    Breastfeeding: insufficient_data

    Dosage Guidelines

    Dosage Used in Studies

    300-600 mg

    Best Time to Take

    Twice daily with meals

    Best Form

    Standardised root extract at 300-600 mg/day, or a fixed combination with saw palmetto

    Bioavailability

    Lignans and sterols are lipophilic and absorb better with dietary fat; secoisolariciresinol lignans are converted by gut microbiota into enterolignans that circulate enterohepatically.

    Forms Compared

    Standardised root extract

    Combination with saw palmetto

    Root powder

    Nettle leaf

    Food & Timing

    With meals, split morning and evening

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.