Stinging Nettle benefit and side effects, Information and herbal supplement product by Ray Sahelian, M.D.
September 24, 2016

Stinging nettle plant (Urtica dioica) is an herb with stinging hairs found in the United States mostly in forests, mountains, weedy, undisturbed areas and roadsides. Extracts of the stinging nettle roots have been used in Germany for prostate health, joint disorders and respiratory health.

Stinging nettle has been shown to inhibit the body from making certain inflammatory chemicals known as prostaglandins. Stinging nettles root may affect hormones levels and proteins in the blood that carry sex hormones (such as testosterone or estrogen). One study described later found its combination with saw palmetto was as good as finasteride (Proscar) in reducing symptoms of prostate enlargement. Stinging nettle appears to also have antioxidant properties. This supplement may be effective for those with allergic rhinitis.

buy Stinging Nettle extract supplement 250 mg
Prostate Power Rx formula stinging nettle leaf is traditionally used as a tonifier and for prostate health. When carefully freeze dried, additional properties are preserved which support the respiratory system. In vitro research of these constituents show partial inhibitory effects on the biosynthesis of arachidonic acid and leukotrienes.


Buy Nettle Root Extract supplement or Prostate Power Rx

Supplement Facts
Serving Size: 2 Vcaps
Servings Per Container: 45
  Amount Per Serving % Daily Value
Total Carbohydrate 0.8 g <1%*
Stinging Nettle Extract* (Urtica dioica) (Root) 500 mg
* Percent Daily Values are based on 2,000 calorie diet.

Supplement Facts:
Stinging Nettle extract 500 mg per two capsules

Suggested Use, dosage: One stinging nettle capsule one or two times daily, or as recommended by your health care professional.

Prostate Power Rx is carefully formulated with important herbs and nutrients to provide optimal prostate health. Significant clinical research on prostate enlargement has been conducted with the potent herbs in Prostate Power Rx. This prostate formula has been designed to support.

Amount per Serving:
Saw Palmetto extract (standardized to contain 45% fatty acids - serenoa repens fruit)
Stinging Nettle 4:1 extract (urtica dioicia root)
Quercetin (one study shows the combination of quercetin and finasteride works very well)
Rosemary 4:1 extract (Rosemarinus officinales leaf)
Beta Sitosterol nutraceutical
Pygeum 4:1 bark extract (Pygeum Africanum)
Daidzein (standardized to contain 40% isoflavones)
(treatment with the isoflavones daidzein and genistein, the estrogen-like compounds found in soy, block prostate growth in rats)
Genistein (standardized to contain 40% isoflavones)
Lycopene (Lycoperscion escatatum fruit)

What's in stinging nettle herb?
Extracts from stinging nettle contain a number of substances including pnenolics and flavonoids such as caffeic acid, malic acid, polysaccharides, and probably many other compounds including lectins, lignans, and phytosterols. 

Extraction and HPLC Analysis of Phenolic Compounds in Leaves, Stalks, and Textile Fibers of Urtica dioica
J Agric Food Chemistry. 2008.
In the present study the phenolic composition of leaves, stalks, and textile fiber extracts from Urtica dioica is described.  The leaves of two stinging nettle samples, cultivated and wild (C and W), contain large amounts of chlorogenic and 2- O-caffeoylmalic acid, which represent 71 and 76% of total phenolics, respectively. Flavonoids are the main class in the stalks: 54% of total phenolics in C and 31% in W samples. Anthocyanins are second in quantitative importance and are present only in nettle stalks: 28% of total phenolics in C and 24% in W extracts.

Allergic rhinitis
Stinging Nettle extract Urtica dioica affects key receptors and enzymes associated with allergic rhinitis.
Phytother Research. 2009. HerbalScience Group LLC, Naples, FL, USA.
Stinging nettle extract shows in vitro inhibition of several key inflammatory events that cause the symptoms of seasonal allergies. These include the antagonist and negative agonist activity against the Histamine-1 (H(1)) receptor and the inhibition of mast cell tryptase preventing degranulation and release of a host of pro-inflammatory mediators that cause the symptoms of hay fevers. The stinging nettle extract also inhibits prostaglandin formation through inhibition of Cyclooxygenase-1 (COX-1), Cyclooxygenase-2 (COX-2), and Hematopoietic Prostaglandin D(2) synthase (HPGDS), central enzymes in pro-inflammatory pathways. These results provide for the first time, a mechanistic understanding of the role of stinging nettle extracts in reducing allergic and other inflammatory responses in vitro.

Blood sugar
Clin Lab. 2013. Improved glycemic control in patients with advanced type 2 diabetes mellitus taking Urtica dioica leaf extract: a randomized double-blind placebo-controlled clinical trial.

Knee pain and osteoarthritis
Nettle sting for chronic knee pain: a randomised controlled pilot study.
Complement Ther Med; Randall C, Dickens A, White A, Sanders H, Fox M. Primary Care Research Group, Peninsula Medical School, Universities of Exeter and Plymouth, United Kingdom.
Patients aged between 55 and 80 years with knee pain and a presumptive clinical diagnosis of osteoarthritis of the knee, with a baseline WOMAC pain subscale score of more than 4 were randomised to receive either treatment with Urtica dioica, or placebo intervention with Urtica galeopsifolia daily for 1 week. The mean reduction in pain score at the end of treatment in the nettles group was 1.7 and in the controls 1.6). All GP practices, and all patients approached, were willing to be involved in the research. Patients liked the treatment mostly because it was 'natural'. The sting was acceptable and viewed as a minor irritation. Research into nettle sting is acceptable to patients and GPs, and patients do not find the treatment more than a minor irritation. Larger rigorous studies are justified to determine the effectiveness of this ancient therapy.

Prostate cancer
Aqueous Extract of Urtica Dioica Makes Significant Inhibition on Adenosine Deaminase Activity in Prostate Tissue from Patients with Prostate Cancer.
Cancer Biol Ther. 2004.
Aim: Investigation of possible effects of aqueous extract of Urtica dioica leaves on adenosine deaminase activity in prostate tissue from patients with prostate cancer. Methods: Ten prostate tissues from patients with pathologically proven localized prostate cancer (Gleason scores 4 to 7) were used in the study. In the tissues, ADA activities with and without preincubation with different amounts of stinging nettle extracts were performed. Results: Aqueous extract of stinging nettle results in significant inhibition on adenosine deaminase (ADA) activity of prostate tissue. ADA inhibition by stinging nettle extract might be one of the mechanisms in the observed beneficial effect of stinging nettle in prostate cancer.

Stinging nettle dosage
The recommended dose of stinging nettle is 50 to 100 mg twice daily.

Stinging nettle side effects, risk
It is possible that consuming high dosages of stinging nettle could lead to hormonal effects.

Gynaecomastia in a man and hyperoestrogenism in a woman due to ingestion of stinging nettle (Urtica dioica).
N Z Med J. 2007. Endocrinology and Metabolic Diseases Department, Baskent University, Ankara, Turkey.
Nettle (Urtica dioica) is commonly sold as a herbal tea in Turkey. We report a case of gynaecomastia in a man (in which the only aetiologic factor identified was nettle tea consumption) and a case of galactorrhoea in a woman (in which the only aetiologic factor identified was also nettle tea ingestion).

What is Gynecomastia and hyperestrogenism? Can nettle supplement pill use cause men to have increased amounts of estrogen along with increased amounts of testosterone?
    Gynecomastia is enlargement of the breast and hyperestrogenism is excess levels in the body of the hormone estrogen.    

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Stinging Nettle Human research studies
Antioxidant, antimicrobial, antiulcer and analgesic activities of stinging nettle (Urtica dioica).
J Ethnopharmacol. 2004.
In this study, water extract of stinging nettle was studied for antioxidant, antimicrobial, antiulcer and analgesic properties. The antioxidant properties of stinging nettle were evaluated using different antioxidant tests, including reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Stinging nettle had powerful antioxidant activity. The 50, 100 and 250 microg amounts of stinging nettle showed 39, 66 and 98% inhibition on peroxidation of linoleic acid emulsion, respectively, while 60 microg/ml of alpha-tocopherol, exhibited only 30% inhibition. Moreover, stinging nettle had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities at the same concentrations. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), quercetin, and alpha-tocopherol. In addition, total phenolic compounds in the stinging nettle were determined as pyrocatechol equivalent. stinging nettle also showed antimicrobial activity against nine microorganisms, antiulcer activity against ethanol-induced ulcerogenesis and analgesic effect on acetic acid-induced stretching.

Stinging nettle root extract (Bazoton-uno) in long term treatment of benign prostatic syndrome (BPS). Results of a randomized, double-blind, placebo controlled multicenter study after 12 months
Urologe A. 2006.
Phytotherapy of BPS has a long tradition in Germany; nevertheless, data referring to single phytotherapeutic agents are rare. We therefore performed a randomized, double-blind, placebo-controlled multicenter study for 1 year with Bazoton uno (459 mg dry extract of stinging nettle roots) with 246 patients. The IPSS decreased with a statistically significant difference compared to placebo. The median Q(max) increased by 3.0 ml/s with stinging nettle in comparison to 2.9 ml/s (placebo), thus not statistically significantly different, as well as the median volume of residual urine, which changed from 35 ml before therapy with stinging nettle to 20 ml and from 40 to 21 ml under placebo application. The number of adverse events as well as urinary infections was smaller under stinging nettle therapy compared to placebo. Treatment with stinging nettle can therefore be considered a safe therapeutic option for BPS, especially for reducing irritative symptoms and BPS-associated complications due to the postulated antiphlogistic and antiproliferative effects of the stinging nettle extract.

Antihyperglycemic activity of the aqueous extract of stinging nettle.
Fitoterapia. 2003.
When administered to rats 30 min before glucose loading, the aqueous extract of  stinging nettle showed a strong glucose lowering effect.

Combined sabal and urtica extract compared with finasteride in men with benign prostatic hyperplasia: analysis of prostate volume and therapeutic outcome.
BJU Int. 2000.
To test the hypothesis that in patients with benign prostatic hyperplasia (BPH), the outcome of drug therapy with finasteride may be predictable from the baseline prostate volume and that positive clinical effects might be expected only in patients with prostate volumes of > 40 mL, using a subgroup analysis of results from a previously reported clinical trial of finasteride and phytotherapy. A subgroup of 431 patients was analysed from a randomized, multicentre, double-blind clinical trial involving 543 patients with the early stages of BPH. Patients received a fixed combination of extracts of saw palmetto fruit (Serenoa repens) and stinging nettle root (Urtica dioica) (PRO 160/120) or the synthetic 5-alpha-reductase inhibitor finasteride. The safety analysis showed that more patients in the finasteride group reported adverse events and also there were more adverse events in this group than in patients treated with stinging nettle. The present analysis showed that the efficacy of both stinging nettle - saw palmetto and finasteride was equivalent and unrelated to prostate volume. However, stinging nettle - saw palmetto had better tolerability than finasteride.

Combined extracts of Stinging nettle and Pygeum africanum in the treatment of benign prostatic hyperplasia: double-blind comparison of two doses.
Clin Ther. 1993.
The 134 patients (aged 53 to 84 years) with symptoms of benign prostatic hyperplasia were drawn from two medical centers in Warsaw. The patients were randomly assigned to receive two capsules of the standard dose of an urtica/pygeum preparation (300 mg of Stinging nettle root extract combined with 25 mg of Pygeum africanum bark extract) or two capsules containing half the standard dose twice daily for 8 weeks. After 28 days' treatment, urine flow, residual urine, and nocturia were significantly reduced in both treatment groups. After 56 days' treatment, further significant decreases were found in residual urine (half-dose group) and in nocturia (both groups). There were no between-group differences in these measures of efficacy. Five patients reported adverse effects of treatment; treatment was not discontinued in any patient because of side effects. It is concluded that half doses of the Stinging nettle/pygeum extract are as safe and effective as the recommended full doses.

Altern Ther Health Med. 2009. Stinging nettle cream for osteoarthritis.

Stinging Nettle Laboratory Studies
Antioxidant, antimicrobial, antiulcer and analgesic activities of nettle.
J Ethnopharmacol. 2004.
In this study, water extract of stinging nettle was studied for antioxidant, antimicrobial, antiulcer and analgesic properties. The antioxidant properties of stinging nettle were evaluated using different antioxidant tests, including reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Stinging nettle had powerful antioxidant activity. Moreover, stinging nettle had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities at the same concentrations. In addition, total phenolic compounds in the stinging nettle were determined as pyrocatechol equivalent. Stinging nettle also showed antimicrobial activity against nine microorganisms, antiulcer activity against ethanol-induced ulcerogenesis and analgesic effect on acetic acid-induced stretching. stinging nettle leaf nettle stinging nettle plant stinging nettle picture stinging nettle stinging tea allergy nettle stinging nettle stinging use cure nettle stinging herb nettle stinging.

Inhibition of the protease activity of the light chain of type A botulinum neurotoxin by aqueous extract from stinging nettle (Urtica dioica) leaf.
Basic Clin Pharmacol Toxicol. 2004.
We investigated the inhibitory effect of stinging nettle leaf extract on the protease activity of botulinum neurotoxin type A and B light chains. The nettle leaf infusion was fractionated and HPLC-based enzymatic assays were performed to determine the capacity of each fraction to inhibit the protease activity of botulinum neurotoxin type A and B light chains. Assay results demonstrated that a water-soluble fraction obtained from the nettle leaf infusion inhibited type A, but did not inhibit type B light chain protease activity. The inhibition mode of water soluble fraction against protease activity of type A light chain was analyzed and found to be a non-competitive.

Stinging Nettle Animal Studies
The role of urtica dioica in the prevention of oxidative stress caused by tourniquet application in rats.
Tohoku J Exp Med. 2005.
Tourniquets are used in extremity surgery and provide a relatively bloodless field, thereby minimizing blood loss and helping identify the vital structures. However, they may cause an ischemia-reperfusion injury with potentially harmful local and systemic consequences. Many therapeutic effects such as diuretic, natriuretic, hypotensive, anti-rheumatic, anti-prostatic, and in-vitro anti-oxidant effects of the stinging nettle have been determined. In the present study, we aimed to investigate the potential role of stinging nettle plant for prevention of oxidative stress in muscle tissues generated by tourniquet application in rats. Wistar rats were used in this study. The stinging nettle extract or 1.15% KCl aqueous solution, in which stinging nettle leaf samples were homogenized, was given to each group of eight rats once a day for 5 days through an intraesophageal canule. No treatment was applied to untreated group. Tourniquets were applied to the left posterior limb of rats for 1 or 2 h followed by a reperfusion period of 1 h. After the ischemia and reperfusion, the rats were killed with a high dose of anesthetic drug, and malonyldialdehyde (MDA) levels were measured in their tibialis anterior muscles. Basal MDA levels were obtained from tibialis anterior muscles of 8 control rats, which were not exposed to ischemia. MDA levels were lower in the stinging nettle-treated rats than those in untreated and KCl-treated rats. These results indicate that stinging nettle has a potential antioxidant effect on ischemic muscle tissues.

Ameliorative effect of IDS 30, a stinging nettle leaf extract, on chronic colitis.
Int J Colorectal Dis. 2004.
Anti-TNF-alpha antibodies are very effective in the treatment of acute Crohn's disease, but are limited by the decline of their effectiveness after repeated applications. The stinging nettle leaf extract, IDS 30, is an adjuvant remedy in rheumatic diseases dependent on a cytokine suppressive effect. We investigated the effect of stinging nettle extract on disease activity of murine colitis in different models. The long-term use of stinging nettle extract is effective in the prevention of chronic murine colitis. This effect seems to be due to a decrease in the Th1 response and may be a new therapeutic option for prolonging remission in inflammatory bowel disease.

Antihyperglycemic activity of the aqueous extract of Urtica dioica.
Fitoterapia. 2003.
When administered 30 min before glucose loading, the aqueous extract of Urtica dioica (250 mg/kg) showed a strong glucose lowering effect. This effect may be caused in part by the reduction of intestinal glucose absorption.

Q. I have read that the stinging nettle extract should come from the root rather than the leaf.

   A. Apparently both the root and leaf extracts of stinging nettle are successfully used in studies. We're not exactly sure what most manufactures are using, but the stinging nettle extract is standardized to 0.8% silic acid.

Q. What's the difference between stinging nettle and nettle leaf?
   A. I'm not sure, I would have to see the actual label on the nettle leaf bottle to see what latin genus name is being used.

The hair on the crown of my head has been thinning and I'm seeing small patches of no hair. I've heard Nettle can help get that hair back. If this thinking is in the ballpark, it it Nettle root, Seed, or plant? At over 40 my prostrate might welcome the courtesy.
   We have not seen any studies evaluating the role of stinging nettle to hair growth in humans.

Can you tell me if this herb is estrogenic? i have had hormone-positive breast cancer but wanted to try nettle for seasonal allergies.
    I am not aware of any studies that have evaluated this herb in terms of its influence on breast cancer. As a general rule, herbs that have phytoestrogens are often of benefit for breast cancer since phytoestrogens do not directly stimulate estrogen positive cells but have a complex effect that often ends up being of benefit.

You often state that one should take a break from various herbal supplements. Would this apply to Nettle Root? If so, how many days should I take a break from it?
    There are no guidelines that apply to everyone, but one or two days a week and a few days a month are a good idea.

Is it possible to order capsules in strength of 150mg, or in plain powder form? I have been ordering the 300mg strength. I have been using the ehrb to relieve severe itching and allergies our dogs have. Since they are different sizes, purchasing the nettle in various strengths would make it easier to dispense. No dog has had a negative reaction and periodic blood tests are Ok. The amount of nettle is based on weight. We’ve tried several different diets based on sensitivities determined from blood tests. Prior to the herbal treatment, the only relief was a cortisone injection and/or frequent use of an antihistamine.
    The 300 mg is the only one we have at this time. This is interesting information.

Stinging nettle leaf infusion has been working very well (as part of a small regimen) for preventing further hairline recession for about a year, but it is looking like stinging nettle leaf is going to be hard to come by (I'd bought two pounds of it a while back and it has lasted a long time--months and months) so I might have to try an extract. This might sound like a silly question, but would a root-and-leaf extract have all the same compounds as my stinging nettle infusion (16oz water + 1/3 C dried and cut stinging nettle leaves)? Will it do the same job? How much of it should I take as a replacement in the event I actually have to start doing that?
   A. I have not studied this topic in detail to know accurately. Usually roots and leaves have some similar compounds but also different ones, too.

The American Herbal Pharmacopoeia (AHP), a California-based non-profit research organization, has released its quality control standards and therapeutic compendium for the popular botanical dietary supplement Stinging Nettle Root (Urtica dioica L.). Each monograph establishes national standards for assuring authenticity, purity, and quality control of the monographed botanical. Accompanying the standards is the AHP Therapeutic Compendium which provides a complete and critical review of the pharmacological and safety data currently available, including information on pharmacokinetics, pharmacodynamics, actions, medical indications, historical and modern and traditional use, structure and function claims, dosages, interactions, side effects, contraindications, toxicology, and more. Nettles roots have historically been used for urinary complaints and the AHP Therapeutic Compendium provides a critical review of the traditional and scientific data. The primary author of the Therapeutics section, which addresses pharmacology and clinical research, Dr. Sigrun Chrubasik, is an expert in clinical botanical medicine research and has published numerous scientific articles on a variety of botanical ingredients, with a focus on pain management and inflammation. According to Dr. Chrubasik’s review, while there is less than definitive data regarding the full clinical utility of nettles roots, the data trends toward efficacy in its beneficial effects in treating prostate enlargement. In the Standards portion of the monograph, the compounds correlated with activity are similarly elusive, though there are indications for potential activity of a number of compounds including sterols, polysaccharides and Urtica dioica agglutinin (UDA). The testing requirements of the AHP monograph differ from those of USP. USP requires analysis of total amino acids as a surrogate marker for the putatively active nettles root protein UDA in addition to the compounds scopoletin and sitosterol. However, the proposed methodology may provide false positive results from degraded UDA, or from other unrelated proteins having a similar amino acid profile. An immunochemical approach, such as ELISA, would be more appropriate; however, the necessary materials are currently unavailable. Similarly, while USP allows for mixtures of Urtica dioica and Urtica urens roots to be acceptable, AHP considers the roots of the two species to be too different to use interchangeably. According to AHP Executive Director Roy Upton, “It is clear that the above ground parts of Urtica species are very similar morphologically, chemically, and therapeutically. However, the roots are completely different in these regards and we do not believe they should be used interchangeably. There is little historical use for Urtica urens roots for urinary tract complaints and no scientific data supporting any such use.”

Nettle Leaf / Root Extract 1~1.5% Silica