By Jessica Johnson, Herbal Science Researcher at Real Herbs | Updated: July 2026 | Reading time: 9 minutes

Understanding Nettle Root's Relationship to Testosterone

This guide covers the honest, accurately-sourced science behind whether and how stinging nettle root affects testosterone, an important distinction between total and free testosterone included.

Total vs. Free Testosterone: A Crucial Distinction

• Total testosterone: Measures all the testosterone in your blood, both bound and unbound.
• Bound testosterone: Most testosterone (around 98%) is bound to proteins, primarily sex hormone-binding globulin (SHBG) and albumin. Bound testosterone is largely inactive and unavailable for your body's cells to use.
• Free testosterone: The small percentage (typically 1-2%) not bound to proteins. This is the biologically active form that can readily enter cells and exert effects throughout the body.

Mechanisms of Action: How Nettle Root May Influence Testosterone

• SHBG modulation: The primary proposed mechanism is that lignans from nettle root bind to human SHBG (PMID 9434605, PMID 7700987), potentially competing with testosterone for binding sites and increasing the level of free (bioavailable) testosterone.
• Anti-inflammatory effects: Chronic inflammation can negatively impact hormone production and endocrine function generally. Nettle root's documented anti-inflammatory properties are relevant background (PMID 17509841).
• Prostate health support: Not a direct testosterone mechanism, but nettle root's well-documented BPH benefits are closely tied to hormonal balance in the prostate specifically, supported by multiple human trials (PMID 7700987, PMID 9270373, PMID 16635963, PMID 23487561, PMID 15748367, PMID 15045190, PMID 32981268).

Scientific Evidence: What the Research Says

• In vitro evidence of SHBG binding: Lignans from nettle root and their metabolites bind to human SHBG (PMID 9434605), direct support for the theoretical mechanism. Further research on nettle root extracts' interaction with SHBG receptors on human prostatic membranes also supports this (PMID 7700987).
• Impact on total testosterone in human trials: A prospective, randomized, double-blind, placebo-controlled crossover study on nettle root for BPH specifically reported that serum total testosterone levels did not change significantly after treatment (PMID 16635963). This suggests nettle root doesn't directly increase overall total testosterone.
• Animal studies and hormonal balance: Animal studies on testosterone-induced prostatic hyperplasia show ameliorative effects, indicating an influence on hormonal balance within the prostate (PMID 21806658, PMID 9270373). Separately, a study on nicotine-induced damage in mice found nicotine significantly decreased testosterone levels, and increasing doses of Urtica dioica extract helped restore testosterone toward normal alongside protecting sperm parameters (Jalili C, Salahshoor MR, Naseri A. Iran J Reprod Med. 2014 Jun;12(6):401-408. PMID 25071848).
• Comprehensive reviews: Reviews of nettle root's efficacy profile discuss its therapeutic uses, including hormonal parameters related to prostate health (PMID 17509841).

Frequently Asked Questions

Will nettle root raise my total testosterone on a blood test?

The evidence doesn't support this. The clearest human trial specifically measured total serum testosterone and found no significant change after treatment. Nettle root's documented mechanism affects the balance between bound and free testosterone, not the total amount your body produces.

Is there any human evidence for the free testosterone claim specifically?

The SHBG-binding mechanism is demonstrated in vitro (lab studies with human SHBG directly), which is genuine, direct evidence for the mechanism. A dedicated human trial specifically measuring free testosterone change with nettle root supplementation would strengthen this further.

Conclusion: A Specific, Modest Mechanism

The evidence suggests nettle root's primary influence is on free (bioavailable) testosterone, through SHBG modulation, rather than directly increasing total testosterone. Human BPH trials haven't shown significant changes in total serum testosterone, but the underlying SHBG-binding mechanism is genuinely documented. For men interested in this specific mechanism, nettle root offers a scientifically-grounded, if modest, natural option, best discussed with a healthcare professional given your individual health picture.

Related Articles

• The Science of Stinging Nettle Root and "Free" Testosterone
• How Nettle Extract Supports Prostate Health

Clinical References

1. Schottner M, Gansser D, Spiteller G. Lignans from the roots of Urtica dioica and their metabolites bind to human sex hormone binding globulin (SHBG). Planta Med. 1997 Dec;63(6):529-32. PMID 9434605
2. Nahata A, Dixit VK. Ameliorative effects of stinging nettle (Urtica dioica) on testosterone-induced prostatic hyperplasia in rats. Andrologia. 2012 May;44 Suppl 1:396-409. PMID 21806658
3. Hryb DJ, Khan MS, Nakhla AM, Rosner W. The effect of extracts of the roots of the stinging nettle (Urtica dioica) on the interaction of SHBG with its receptor on human prostatic membranes. Planta Med. 1995 Feb;61(1):31-2. PMID 7700987
4. Lichius JJ, Muth C. The inhibiting effects of Urtica dioica root extracts on experimentally induced prostatic hyperplasia in a rodent model. Planta Med. 1997 Aug;63(4):307-10. PMID 9270373
5. Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. J Herb Pharmacother. 2005;5(4):1-11. PMID 16635963
6. Ghorbanibirgani A, Khalili A, Zamani L. The efficacy of stinging nettle (Urtica dioica) in patients with benign prostatic hyperplasia: a randomized double-blind study in 100 patients. Iran Red Crescent Med J. 2013 Jan;15(1):9-10. PMID 23487561
7. Chrubasik JE, Roufogalis BD, Wagner H, Chrubasik S. A comprehensive review on the stinging nettle effect and efficacy profiles. Part II: urticae radix. Phytomedicine. 2007 Aug;14(7-8):568-79. PMID 17509841
8. Melo EA, Bertero EB, Rios LA, Mattos D Jr. Evaluating the efficiency of a combination of Pygeum africanum and stinging nettle (Urtica dioica) extracts in treating benign prostatic hyperplasia: double-blind, randomized, placebo-controlled trial. Int Braz J Urol. 2002 Sep-Oct;28(5):418-25. PMID 15748367
9. Schneider T, Rubben H. Stinging nettle root extract (Bazoton-uno) in long term treatment of benign prostatic syndrome (BPS). Results of a randomized, double-blind, placebo controlled multicenter study after 12 months. Urologe A. 2004 Mar;43(3):302-6. PMID 15045190
10. Karami AA, Sheikhsoleimani M, Memarzadeh MR, et al. Urtica Dioica Root Extract on Clinical and Biochemical Parameters in Patients with Benign Prostatic Hyperplasia, Randomized Controlled Trial. Pak J Biol Sci. 2020;23:1338-1344. PMID 32981268
11. Jalili C, Salahshoor MR, Naseri A. Protective effect of Urtica dioica L against nicotine-induced damage on sperm parameters, testosterone and testis tissue in mice. Iran J Reprod Med. 2014 Jun;12(6):401-408. PMID 25071848

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