Stinging Nettle Root, Testosterone and SHBG
By Real Herbs Editorial Team · Published October 2026 · Updated October 2026 · 7 min read
Key takeaway: In the trials and regulatory documents cited here, stinging nettle root did not change testosterone in men with BPH symptoms: it was unchanged in the 620-man trial, and the EMA reports no significant change in sex hormone parameters in two of three studies. What did change in all three EMA-described studies was blood SHBG, the protein that carries sex hormones, which fell with a methanol extract. Laboratory work suggests nettle root compounds can bind SHBG, and the effect depends on the extract, so these findings should not be read as a testosterone boost.
Search for stinging nettle root (Urtica dioica) and you will find claims that it raises "free" testosterone. The research behind those claims is about a protein called sex hormone binding globulin (SHBG). This guide sets out what SHBG is, what laboratory and human studies report about nettle root and SHBG, and what has been measured for testosterone.
Disclosure: Real Herbs sells a stinging nettle root extract. We report each result as it was published, and the studies did not test this exact product.
What SHBG is
Sex hormone binding globulin (SHBG) is a blood protein that determines the balance between free and protein-bound androgens and oestrogens, and so regulates how much reaches target tissues ([1], PMID 31852737). A change in SHBG can in principle change how much testosterone is free, which is why the topic appears in nettle root research and in marketing.
Two points keep this in perspective. First, SHBG is one of several mechanisms discussed for nettle root, and the EMA describes the mechanism of action as unclear. Second, a change in a blood marker is not the same as a change in how a man feels or in his symptoms.
Laboratory studies on SHBG
Four laboratory studies tested nettle root extracts or compounds against SHBG. They used test tubes and cell cultures, not men.
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| Study | What was tested | What was reported | Limits |
|---|---|---|---|
| Hryb 1995 | Four root materials (aqueous extract, alcoholic extract, U. dioica agglutinin, stigmast-4-en-3-one) on SHBG binding to its receptor on human prostate membranes | Only the aqueous extract was active; it inhibited binding in a dose-related way from about 0.6 mg/mL and completely at 10 mg/mL ([2], PMID 7700987) | Test-tube assay; the alcoholic extract was not active |
| Gansser and Spiteller 1995 | Nettle root extracts in a test system for compounds that interfere with SHBG | The lignan secoisolariciresinol and a mixture of trihydroxy fatty acids reduced SHBG binding activity ([3], PMID 7702715) | Test-tube assay |
| Schöttner 1997 | Six root lignans and their gut-derived products | All lignans except (-)-pinoresinol bound SHBG in vitro, and (-)-3,4-divanillyltetrahydrofuran had a particularly high affinity ([4], PMID 9434605) | Test-tube assay; binding is not the same as a hormone change in men |
| Round 2019 | Crystal structures and cell culture with the root lignan (-)-3,4-divanillyltetrahydrofuran (DVT) | DVT bound SHBG with relatively low affinity, and in a cell-culture androgen reporter system it increased testosterone activity by displacing testosterone from SHBG; binding was almost lost in the presence of zinc ([1], PMID 31852737) | Cell culture and structural work with a single compound |
Cell study Taken together, these studies suggest that some compounds in nettle root can bind SHBG, and one shows how this could free testosterone in a cell culture. The same effect has not been reported in a living man, and the active material in Hryb 1995 was the aqueous extract.
What was measured in men
Regulatory report The EMA assessment report describes three clinical studies of a dried nettle root extract (drug-extract ratio 7 to 14:1, extracted in 20% methanol) that measured serum hormones, including testosterone, 5-alpha-DHT, oestradiol, oestrone and SHBG. SHBG decreased significantly in all three studies. Two of the studies found no significant change in sex hormone parameters, and the third (Bauer 1988) reported differences in PSA, oestradiol, oestrone and SHBG over 12 weeks but did not publish further data, so the EMA could not evaluate it ([5]).
Human trial In the 620-man trial, PSA and testosterone were unchanged after treatment ([6], PMID 16635963). That trial also carries the caveats set out in our urinary flow guide: it has not been repeated at that scale, and PubMed lists some other papers by the same author as retracted; this paper is not marked as retracted.
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| Measure | What was reported | Source |
|---|---|---|
| SHBG | Fell significantly in three studies of a 20% methanol extract | ([5]) |
| Testosterone | Unchanged in the 620-man trial; sex hormone parameters not significantly changed in two EMA-described studies | ([6], PMID 16635963; [5]) |
| PSA | Unchanged in the 620-man trial | ([6], PMID 16635963) |
| 5-alpha-DHT | Listed among hormones measured in the EMA-described studies; see our DHT guide | ([5]) |
What a lower SHBG means for a man taking nettle root is not clear from these reports, because testosterone did not change in the studies that report it.
Why the extract matters
The findings above come from different materials, and the studies do not line up neatly:
- Aqueous (water) extract: the only material active against SHBG binding to its prostate receptor in the 1995 test-tube study.
- Alcoholic extract: not active in that same assay.
- 20% methanol extract: used in the clinical studies in which SHBG fell.
- Isolated lignans: bound SHBG in test tubes, and one lignan (DVT) was explored in cell culture.
Because results depend on the solvent, the extract ratio and the dose, a finding for one material cannot be assumed for another, including a commercial capsule. The Real Herbs product is a 10:1 root extract, and none of these studies tested it.
Does nettle root raise testosterone?
Review A 2019 review of herbs and testosterone found moderate evidence for several other herbs, such as ashwagandha, fenugreek and mucuna, and discussed Urtica dioica among herbs with favourable and promising evidence for prostate health ([7], PMID 30790614). The nettle root trials cited here enrolled men with BPH symptoms and not men with low testosterone, so they do not answer whether nettle root changes testosterone in other groups.
In the sources cited here, testosterone did not change in the men studied, and SHBG was the marker that moved. If you are looking to raise testosterone, talk to your doctor about testing and treatment, because nettle root has not been studied for that goal in the sources cited here.
What this means for you
- Not a testosterone booster: the studies cited here did not find a testosterone rise, and none was designed to test one.
- Hormone tests: tell your doctor about any supplement before hormone blood tests or treatment, because the effect of nettle root on SHBG has been measured in few studies.
- Existing conditions: if you have a hormone-related condition or take hormone treatment, ask your doctor first. Our safety guide and interactions guide cover who should check first.
- BPH symptoms: for what trials report on prostate symptoms, see our BPH guide.
Frequently asked questions
Does stinging nettle root raise testosterone?
Not in the studies cited here. Testosterone was unchanged in the 620-man trial, and the EMA reports no significant change in sex hormone parameters in two of the three studies it describes. These studies enrolled men with BPH symptoms.
Does nettle root increase free testosterone?
This has not been shown in men. A cell-culture study found that a nettle root lignan can displace testosterone from SHBG, which is a possible mechanism, but SHBG fell in men without a reported testosterone change.
What is SHBG?
Sex hormone binding globulin is a blood protein that carries androgens and oestrogens and regulates how much reaches tissues.
Does nettle root lower SHBG?
In the EMA report, SHBG fell significantly in three clinical studies of a 20% methanol root extract. What this means for symptoms or health is not clear from those reports.
Does nettle root affect oestrogen?
The EMA lists oestradiol and oestrone among the hormones measured. Two studies found no significant change in sex hormone parameters, and a third reported differences but did not publish further data.
Does the type of extract matter?
Yes. In a test-tube study only the aqueous extract blocked SHBG binding to its prostate receptor, while the clinical studies used a 20% methanol extract. A finding for one extract cannot be assumed for another.
Is nettle root a natural testosterone booster?
The sources cited here do not support that. If you are concerned about low testosterone, ask your doctor about testing.
Should I tell my doctor before hormone tests?
Yes. Mention any supplement, including nettle root, before hormone blood tests or treatment.
Is this about nettle root or nettle leaf?
Nettle root. Leaf is a different material studied for different purposes, so findings about leaf should not be read across to the root.
The bottom line
The research linking nettle root to testosterone is really about SHBG. Laboratory studies show that some root compounds bind SHBG, and SHBG fell in clinical studies of a methanol extract, but testosterone did not change in the men studied. Results depend on the extract used, so nettle root should not be treated as a testosterone booster. If hormones are a concern, speak to your doctor.
Real Herbs Stinging Nettle Root Extract: 750 mg of 10:1 root extract per capsule (about 7,500 mg dried root equivalent), 100 vegetarian capsules. Backed by our 100-Day Money-Back Guarantee. Real Herbs sells this product. The trials and the EMA documents did not test this exact product.
Related reading
- Stinging nettle root for BPH: what the research shows
- Does stinging nettle root block DHT?
- Nettle root side effects and who should avoid it
References
- Round P, Das S, Wu TS, Wähälä K, Van Petegem F, Hammond GL. Molecular interactions between sex hormone-binding globulin and nonsteroidal ligands that enhance androgen activity. J Biol Chem. 2020;295(5):1202-1211. PMID 31852737 · DOI 10.1074/jbc.RA119.011051
- Hryb DJ, Khan MS, Romas NA, 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;61(1):31-2. PMID 7700987 · DOI 10.1055/s-2006-957993
- Gansser D, Spiteller G. Plant constituents interfering with human sex hormone-binding globulin. Evaluation of a test method and its application to Urtica dioica root extracts. Z Naturforsch C J Biosci. 1995;50(1-2):98-104. PMID 7702715
- Schöttner 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;63(6):529-32. PMID 9434605 · DOI 10.1055/s-2006-957756
- European Medicines Agency, Committee on Herbal Medicinal Products. Assessment report on Urtica dioica L.; Urtica urens L., radix. EMA/HMPC/322627/2023. Final, Revision 1, 22 January 2025. ema.europa.eu
- 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
- Santos HO, Howell S, Teixeira FJ. Beyond tribulus (Tribulus terrestris L.): the effects of phytotherapics on testosterone, sperm and prostate parameters. J Ethnopharmacol. 2019;235:392-405. PMID 30790614 · DOI 10.1016/j.jep.2019.02.033
Disclaimer: This article is for educational purposes only and is not medical advice. Talk with a qualified healthcare professional before starting any supplement, especially if you have a medical condition or take medication. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
