Nettle may be effective in relieving symptoms of benign prostatic hyperplasia (BPH), or enlarged prostate.
Researchers are still unsure how nettle works. It has been suggested that nettle might reduce the activity of testosterone by altering the amount of it 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.
To treat allergies
No scientific evidence supports this use.
To treat arthritis
Clinical trials support the topical use of nettle for arthritis of the hip, knee, and hand. Larger studies are needed to confirm these data.
To treat benign prostatic hypertrophy (BPH)
When combined with other herbs, nettle has shown positive results in clinical trials.
To clear up chest congestion
There is no evidence to back this claim.
To promote urination
Nettle is a known diuretic.
To reduce inflammation
Nettle may have anti-inflammatory activities, but clinical trials have yet to be conducted.
To treat oily skin
No scientific evidence supports this use.
To calm muscle spasms
This use is not backed by research.
To treat urinary tract disorders and relieve difficult or painful urination
Nettle was shown to have beneficial effects in clinical studies.
You are taking diuretics: Nettle can have additive effects.
You are taking hypotensive drugs: Nettle has hypotensive action and may have additive effects.
You are taking cytochrome P450 substrate drugs: Nettle may increase the risk of side effects of these drugs.
A case of enlarged breasts has been reported in a man following consumption of nettle tea.
Nipple discharge was reported in a woman after ingestion of nettle tea.
A breastfed, 17-day-old infant developed hives following the mother’s use of water boiled with stinging nettle to heal nipple cracks.
Low blood sugar was reported in a 78-year-old man after taking an herbal remedy containing nettle for benign prostatic hypertrophy.
Nettle is a perennial herbaceous flowering plant, native to Asia, Europe, and North America. The root is widely used to treat benign prostatic hypertrophy (BPH), allergies, arthritis, and inflammation. Nettle 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 reno- (1) and hepatoprotective (2) properties, and is effective against colitis in mice (3).
Data from a few clinical trials suggest benefits of nettle in the treatment of osteoarthritis of hip, knee (4) and hand (5) and in ameliorating symptoms associated with benign prostatic syndrome (BPS) (6)(7)(8). In another study nettle improved glycemic control in type-2 diabetic patients (9).
Nettle may also have anticancer potential. It demonstrated anti-proliferative effects in human prostate cancer cells (10), and protected against cisplatin-induced toxicity (11).
Benign prostatic hypertrophy (BPH)
Urinary tract disorders
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 (H1) receptor and inhibition of prostaglandin formation via inhibition of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and hematopoietic prostaglandin D2 synthase (HPGDS), key enzymes in pro-inflammatory pathways (2).
A number of compounds in essential oil derived from nettle including carvacrol may have cytotoxic and genotoxic effects (12).
A methanolic extract of nettle reduced experimentally induced prostatic hyperplasia in mice (17).
A case of gynecomastia was reported in a man following consumption of nettle tea (15).
Galactorrhea was reported in a woman after ingestion of nettle tea (15).
A breastfed, 17-day-old infant developed urticaria following the mother’s use of water boiled with stinging nettle to heal nipple cracks (16).
Hypoglycemia was reported in a 78-year-old man after taking an herbal remedy containing nettle for benign prostatic hypertrophy (17).
Cytochrome P450 substrates: Nettle inhibits cytochrome P450 enzymes and may affect the intracellular concentration of drugs metabolized by these enzymes (18).
Diuretics: Theoretically nettle may have an additive effect due to its diuretic activity (19).
Hypotensives: Nettle has hypotensive action and may enhance the effects of hypotensive drugs (19).