

Stinging nettle, common nettle, greater nettle
The root of nettle is widely used to treat benign prostatic hypertrophy (BPH), allergies, arthritis, and inflammation. It is usually combined with herbs such as saw palmetto and pygeum for the treatment of BPH. Several compounds have been isolated from nettle including flavonoid glycosides that appear to contribute to its biological effects, although the precise mechanism of action is unclear.
In vitro and animal studies indicate that nettle extract has anti proliferative effects in human prostate cancer cells (6) and protects against cisplatin-induced toxicity (15). It was also shown effective against colitis in mice (16).
Data from a few clinical trials suggest benefits of nettle in the treatment of osteoarthritis of hip, knee (10) and hand (14) and in ameliorating symptoms associated with benign prostatic syndrome (BPS) (8) (11) (12). Larger studies are needed to establish use of nettle.
In vitro studies show that nettle extract inhibits several inflammatory events that are responsible for the symptoms of seasonal allergies (2). They include the antagonist and negative agonist activity against the histamine-1 (H(1)) receptor and inhibition of prostaglandin formation via inhibition of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and hematopoietic prostaglandin D(2) synthase (HPGDS), key enzymes in pro-inflammatory pathways (2).
A methanolic extract of nettle reduced experimentally induced prostatic hyperplasia in mice (17).
Reported:
A case of gynecomastia has been reported in a man following consumption of nettle tea (13).
Galactorrhea was reported in a woman after ingestion of nettle tea (13).
A breastfed, 17-day-old infant developed urticaria following the mother’s use of water boiled with stinging nettle to heal nipple cracks (5).
Hypoglycemia has been reported in a 78-year-old man after taking an herbal remedy containing nettle for benign prostatic hypertrophy (18).
Uslu S, Bulbul A, Diler B, Bas EK, Nuhoglu A. Urticaria due to Urtica dioica in a neonate. Eur J Pediatr. 2011 Mar;170(3):401-3.
Konrad L, et al. Antiproliferative effect on human prostate cancer cells by a stinging nettle root (Urtica dioica) extract. Planta Med 2000;66:44-7.
Tahri A, Yamani S, Legssyer A, et al. Acute diuretic, natriuretic and hypotensive effects of a continuous perfusion of aqueous extract of Urtica dioica in the rat. J Ethnopharmacol. 2000 Nov;73(1-2):95-100.
Bottom Line: Nettle may be effective in relieving symptoms of benign prostatic hyperplasia (BPH).
Researchers are still unsure how nettle works. It has been suggested that nettle might reduce the activity of testosterone by altering the amount of testosterone circulating in the blood, or by inhibiting one of the key enzymes in testosterone synthesis. However, none of these theories has been conclusively proven. Other actions of nettle include acting as a diuretic (causing water loss from the body through the urine) and lowering blood pressure. Some compounds in nettle also reduce inflammation.
Benign prostatic hypertrophy (BPH)
A few clinical trials have used nettle in combination with other herbs for the treatment of benign prostatic hypertrophy (BPH), with positive results.
You are taking drugs that are substrates of Cytochrome P450 (nettle may increase the risk of side effects of these drugs).
Reported:
A case of gynecomastia has been reported in a man following consumption of nettle tea.
Galactorrhea was reported in a woman after ingestion of nettle tea.
A breastfed, 17-day-old infant developed urticaria following the mother’s use of water boiled with stinging nettle to heal nipple cracks.
Hypoglycemia has been reported in a 78-year-old man after taking an herbal remedy containing nettle for benign prostatic hypertrophy.