Stinging Nettle (Urtica dioica, Urticaceae)

By Dr. Ashraf Girgis
Published April 2024

Stinging Nettle belongs to the Urticaceae family. It is a biennial herb commonly grown in Asia, the Mediterranean region, Africa, and Europe. In North America and Canada, it has long been used by indigenous peoples for food and medicinal purposes. The entire plant can be used: the aerial part can be eaten in a salad, and the root can be used to make a healthy beverage or soup for its medicinal effects.

Constituents:

Stinging nettle has many beneficial constituents. It contains flavonoids (gallic acid, vanillic acid, syringic acid, protocatechuic acid, gentisic acid), several fatty acids, and many amino acids such as alanine, γ-aminobutyric acid (GABA), glutamic acid, isoleucine, leucine, phenylalanine, proline, tyrosine, and valine. It also contains many vitamins, including vitamin A and vitamin C—actually more vitamin C than orange juice! Its hairs contain important neurotransmitters such as serotonin and acetylcholine. It also has many other vitamins and minerals.

Stinging nettle has also traditionally been used as a diuretic, wound treatment, and for healing coughs and colds.

Here are some of its most important benefits:

Anti-Inflammatory and Pain Benefits

In various studies using the leaves, stems, roots, and flowers of stinging nettle, scientists found strong anti-inflammatory benefits (Obertreis et al.). Using ethanol extract of stinging nettle suppressed both the TNF-α (a proinflammatory cytokine) and IL-1β (a key indicator of inflammatory response) released in the blood.

In another study by Sabzar et al., various solvents used on animals reduced inflammation. The hexane stinging nettle extract showed a significant anti-inflammatory response compared to indomethacin (anti-inflammatory medication), with the edema in animal paws reduced by 53.4%. In another study, 81 patients with primarily hip and knee joint arthritis pain—who were taking NSAIDs or analgesics regularly—were given vitamin E, fish oil, and stinging nettle. After three months, the patients’ use of NSAIDs decreased by 20%, and analgesics decreased by 50%.

In another study on animals, the stinging nettle gel prepared using Carbopol 934 (a thickening polymer) showed 58.21% analgesia, compared to 61.19% analgesia for the indomethacin (anti-inflammatory drug) gel standard in a writhing test. It showed 55.05% inhibition of edema in animal paws, comparable to that of the standard gel (53.93%).

Cardiovascular Effects

In another study by Tahri et al., using the perfusion of 24 mg/kg/h of stinging nettle extract reduced arterial blood pressure by 38%. In that study, scientists used various doses of stinging nettles and reduced blood pressure by 15%-38%, compared to no change in the control group. Among various preparations used, the one prepared with ethyl acetate showed the best antihypertensive activities.

Benign Prostatic Hyperplasia (BPH)

In a study of men with Benign Prostatic Hyperplasia (BPH), stinging nettle showed a significant reduction in prostate size, as well as a reduction in IPSS (International Prostate Symptom Score) and a reduction in PSA (prostate-specific antigen). The anti-inflammatory effects and modulation of the immune system responsible for such reductions are due to compounds such as lignans, polysaccharides, and phytosterols. The study was conducted with 287 men. During the study, two capsules of 300 mg of stinging nettle were given twice a day. The study was conducted in 2011 at Azad University, Gachsaran, Iran.

Effect on Blood Sugar

Stinging nettle is also known to lower blood sugar. In a study conducted in 2015, patients with diabetes were given 500 mg of stinging nettle extract three times a day for a period of three months, in conjunction with their regular oral antihyperglycemic medications. It lowered their fasting blood sugar and HbA1c significantly. The researchers concluded that stinging nettle can be used in conjunction with other antihyperglycemic medications to safely improve blood sugar levels. The study was conducted by Iranian scientists on 46 patient participants with type 2 diabetes mellitus. The mechanism of action in patients with type 2 diabetes is attributed to its phenolic (carbolic acid) compounds, which lower the main enzymes involved in type 2 diabetes (alpha-glucosidase and alpha-amylase).

Overall, stinging nettle has shown many benefits due to its cardiovascular protective activities and its antioxidative, anti-inflammatory, anti-ulcer, anti-hyperglycemic, and antibacterial effects. In general, it has also been shown to be effective for patients with allergies, arthritis, spasms, urinary problems, and congestion.

Side Effects:

Urticaria (skin reactions and hives) and pain after using stinging nettle, requiring ICU admission, have been reported in Australia.

In addition to skin allergies, allergic rhinitis, hypoglycemia, an increase in breast size (gynecomastia) in men due to hormonal imbalances, and milky discharge from the breast (galactorrhea) have also been observed.

References

1. Dar, S. A., Ahmad, F., Ganai, A. R., Yousuf, M., Hassan, M. U., Balkhi, T. O., Bhat, M., & Sharma, P. (2013). Pharmacological and toxicological evaluation of Urtica dioica. Pharmaceutical Biology, 51(2), 170–180. https://doi.org/10.3109/13880209.2012.705351

2. Medical News Today. (2018, May 9). What is stinging nettle? Medical News Today. https://www.medicalnewstoday.com/articles/325244#what-is-stinging-nettle

3. Razavi, M., & Shaterian, A. (2003). A double-blind, placebo-controlled study of Urtica dioica in the treatment of benign prostatic hyperplasia. International Journal of Urology, 10(1), 69-72. https://doi.org/10.1580/1080-6032(2003)014[0069:AADPSC]2.0.CO;2

4. National Center for Biotechnology Information (NCBI). (2012). Clinical implications of the use of Urtica dioica in benign prostatic hyperplasia. PubMed Central. https://pubmed.ncbi.nlm.nih.gov/22593694/

5. National Center for Biotechnology Information (NCBI). (2013). Urtica dioica in the treatment of diabetes and its associated metabolic disorders. PubMed Central. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3714593/

6. SAGE Journals. (2004). Clinical and experimental study of nettle leaves. Clinical Therapeutics, 26(10), 1432-1440. https://journals.sagepub.com/doi/abs/10.1580/1080-6032%282003%29014%5B0069%3A%5D2.0.CO%3B2

7. National Center for Biotechnology Information (NCBI). (2011). Urtica dioica extract for chronic prostatitis: a clinical trial. PubMed Central. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003499/

8. Clinical Lab Publications. (2015). The role of stinging nettle in inflammation management. Clinical Lab Studies, 11(2), 57-63. https://www.clin-lab-publications.com/article/1208

9. Medical News Today. (2018, June 18). Health benefits of nettle. Medical News Today. https://www.medicalnewstoday.com/articles/320573

10. Memorial Sloan Kettering Cancer Center (MSKCC). (n.d.). Nettle. MSKCC Integrative Medicine. https://www.mskcc.org/cancer-care/integrative-medicine/herbs/nettle