Stinging Nettle Root, Blood Pressure and Heart Health
By Real Herbs Editorial Team · Published October 2026 · Updated October 2026 · 7 min read
Key takeaway: We found no human trial of nettle root that measured blood pressure. The root has been tested in one laboratory and animal study, and most other blood pressure work in animals used leaf or unspecified extracts. In people, a pooled analysis of 13 trials in type 2 diabetes reported systolic pressure about 5 mmHg lower, while two single trials found no change, and none of these studied nettle root alone.
Nettle (Urtica dioica) has a long traditional reputation in some regions as a remedy for high blood pressure, so people often ask whether nettle root affects blood pressure or the heart. This guide sets out what laboratory, animal and human studies report, which plant part each used, and what to do if you take blood pressure medicines.
Disclosure: Real Herbs sells a stinging nettle root extract. We report each study as it was published, and none of them tested this product.
Laboratory and animal studies
Several groups have tested nettle extracts on blood vessels, hearts and blood pressure in animals. Only one of the studies below used root, and several do not name the plant part in their abstracts.
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| Study | Model | Plant part | What was reported |
|---|---|---|---|
| Testai 2002 | Rat aorta, guinea pig atria and anaesthetised rats | Root extracts (aqueous and methanolic) | Vessel-relaxing action in aortic rings with intact lining, which was blocked by inhibitors of nitric oxide and potassium channels; a marked but transient fall in blood pressure in anaesthetised rats ([1], PMID 12020933) |
| Tahri 2000 | Anaesthetised rats, intravenous infusion | Aqueous extract of aerial parts | Blood pressure fell by 15% and 38% at the low and high dose, with more urine and sodium excretion; the effect of the high dose persisted, and the authors suggested a possible toxic effect at that dose ([2], PMID 11025144) |
| Legssyer 2002 | Isolated rat heart and aorta | Aqueous extract (part not named in the abstract) | Slower heart rate, which stopped the isolated heart at the highest concentration tested, and a rise in tone of the isolated aorta; the authors suggest the slower heart rate may offset the effect on vessels ([3], PMID 12237804) |
| Qayyum 2016 | Rats and isolated rat and rabbit aortae | Methanolic extract and fractions (part not named in the abstract) | A larger fall in blood pressure in hypertensive rats than in normal rats, vessel relaxation and calcium channel blocking activity similar to verapamil in the dish ([4], PMID 27585814) |
| Vajic 2018 | Spontaneously hypertensive rats; 4 weeks | Leaf extract, 10, 50 and 200 mg/kg a day | All three doses lowered systolic and diastolic pressure; losartan was the comparison drug ([5], PMID 30097121) |
Animal study These studies show that nettle extracts act on blood vessels and the heart in laboratory settings, through nitric oxide, potassium and calcium channels in some experiments. They used animals and isolated tissue, with doses and concentrations that cannot be compared directly with a capsule, and one study reported a possible toxic effect at its high dose, so they do not tell us what a capsule does in a person.
What studies in people report
We found no trial in people that was designed to test nettle for high blood pressure. Blood pressure appears as a secondary result in trials of type 2 diabetes:
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| Study | People and length | Product | Blood pressure result |
|---|---|---|---|
| Kianbakht 2013 | 92 people; 3 months | Nettle leaf extract added to usual diabetes medicines | No significant effect on systolic or diastolic pressure compared with placebo ([6], PMID 24273930) |
| Khalili 2017 | 60 people; 90 days | Mix of nettle leaves, milk thistle seed and olibanum resin | No significant blood pressure lowering effect ([7], PMID 29228792) |
| Tabrizi 2022 (pooled analysis) | 13 trials in type 2 diabetes | Nettle products of various kinds | Systolic pressure lower by 5.03 mmHg (95% CI 8.15 to 1.91); diastolic pressure lower by 1.35 mmHg, not statistically significant ([8], PMID 34587883) |
These results come from people with diabetes, so they may not apply to people without it. The pooled analysis combines trials of different products, and the abstract does not give the plant part for each one ([8], PMID 34587883). Both single trials used leaf or a leaf mix, and neither found a blood pressure change ([6], PMID 24273930; [7], PMID 29228792).
What about nettle root
The EMA assessment report for nettle root lists one traditional use: relief of lower urinary tract symptoms related to benign prostatic hyperplasia (BPH), after a doctor has excluded serious conditions ([9]). It does not list blood pressure or heart health as a use. The only root study we found on the circulation is the laboratory and animal work by Testai and colleagues above ([1], PMID 12020933), and the trials in men with BPH that we cite elsewhere were not set up to track blood pressure. Our root versus leaf guide explains why leaf findings should not be read across to root.
If you take blood pressure medicines
- Do not stop or reduce medicine. Nothing cited here supports using nettle in place of blood pressure treatment.
- Tell your prescriber. No study of nettle root with blood pressure medicines was found, so how they combine is not known. See our interactions guide.
- Keep your checks. Carry on with any home or clinic blood pressure checks you have been asked to do, and report dizziness or changes.
- Mention water pills. Some animal work found more urine and sodium loss with nettle extract ([2], PMID 11025144), so tell your prescriber if you take a diuretic for blood pressure, heart or kidney reasons.
When to see a doctor
High blood pressure and heart conditions need medical assessment and are not something to manage with a supplement alone. Get your blood pressure measured regularly, and see a doctor promptly for chest pain, breathlessness, fainting or a sudden severe headache. For general side effects and who should check first, see our safety guide.
Frequently asked questions
Does nettle root lower blood pressure?
We found no human trial of nettle root that measured blood pressure. The root has been tested in one laboratory and animal study, which reported a transient fall in blood pressure in anaesthetised rats.
Does nettle leaf lower blood pressure?
Leaf extract lowered blood pressure in a rat model of hypertension. In people with type 2 diabetes, two single trials found no change, while a pooled analysis of 13 trials reported systolic pressure about 5 mmHg lower.
Can I take nettle root with blood pressure medicine?
No study of the combination was found. Tell your prescriber before you start, and keep the checks they have asked for.
Is nettle root good for the heart?
The heart studies we found were in animals or isolated tissue, and most did not use root. We found no human trial of nettle root on heart outcomes.
Does nettle act as a diuretic?
An extract of the aerial parts increased urine and sodium excretion in rats. We found no human trial of nettle root as a diuretic. See our kidney and urinary tract guide.
Could nettle make my blood pressure too low?
No study found tested this in people taking blood pressure medicines. Because blood pressure fell in some animal experiments, report any dizziness to your doctor.
Why do some websites say nettle root treats high blood pressure?
Traditional use of the plant in some regions includes high blood pressure, and laboratory work has explored how extracts act on vessels. Trials in people have not yet tested nettle root for this.
Should I check my blood pressure while taking nettle root?
It is sensible to keep regular checks whether or not you take a supplement, and to share the readings with your doctor.
The bottom line
Nettle extracts act on blood vessels and the heart in animal and laboratory studies, but nettle root has not been tested for blood pressure in people in the studies we found, and the leaf and mixed trials in diabetes report mixed results. If you have high blood pressure or take medicine for it, keep your treatment, tell your doctor about any nettle product, and keep your regular checks.
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
- Nettle root vs nettle leaf: key differences
- Nettle root and blood sugar
- Nettle root and medicine interactions
- Nettle root, kidney and urinary tract health
References
- Testai L, Chericoni S, Calderone V, Nencioni G, Nieri P, Morelli I, Martinotti E. Cardiovascular effects of Urtica dioica L. (Urticaceae) roots extracts: in vitro and in vivo pharmacological studies. J Ethnopharmacol. 2002;81(1):105-9. PMID 12020933 · DOI 10.1016/s0378-8741(02)00055-7
- Tahri A, Yamani S, Legssyer A, Aziz M, Mekhfi H, Bnouham M, Ziyyat A. Acute diuretic, natriuretic and hypotensive effects of a continuous perfusion of aqueous extract of Urtica dioica in the rat. J Ethnopharmacol. 2000;73(1-2):95-100. PMID 11025144 · DOI 10.1016/s0378-8741(00)00270-1
- Legssyer A, Ziyyat A, Mekhfi H, Bnouham M, Tahri A, Serhrouchni M, Hoerter J, Fischmeister R. Cardiovascular effects of Urtica dioica L. in isolated rat heart and aorta. Phytother Res. 2002;16(6):503-7. PMID 12237804 · DOI 10.1002/ptr.1087
- Qayyum R, Qamar HM, Khan S, Salma U, Khan T, Shah AJ. Mechanisms underlying the antihypertensive properties of Urtica dioica. J Transl Med. 2016;14(1):254. PMID 27585814 · DOI 10.1186/s12967-016-1017-3
- Vajic UJ, Grujic-Milanovic J, Miloradovic Z, Jovovic D, Ivanov M, Karanovic D, Savikin K, Bugarski B, Mihailovic-Stanojevic N. Urtica dioica L. leaf extract modulates blood pressure and oxidative stress in spontaneously hypertensive rats. Phytomedicine. 2018;46:39-45. PMID 30097121 · DOI 10.1016/j.phymed.2018.04.037
- 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. Clin Lab. 2013;59(9-10):1071-6. PMID 24273930 · DOI 10.7754/clin.lab.2012.121019
- Khalili N, Fereydoonzadeh R, Mohtashami R, Mehrzadi S, Heydari M, Huseini HF. Silymarin, olibanum, and nettle, a mixed herbal formulation in the treatment of type II diabetes: a randomized, double-blind, placebo-controlled, clinical trial. J Evid Based Complementary Altern Med. 2017;22(4):603-608. PMID 29228792 · DOI 10.1177/2156587217696929
- Tabrizi R, Sekhavati E, Nowrouzi-Sohrabi P, Rezaei S, Tabari P, Ghoran SH, et al. Effects of Urtica dioica on metabolic profiles in type 2 diabetes: a systematic review and meta-analysis of clinical trials. Mini Rev Med Chem. 2022;22(3):550-563. PMID 34587883 · DOI 10.2174/1389557521666210929143112
- 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
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.
