Stinging nettle side effects

Overview

Stinging nettle

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Table of Contents > Herbs > Stinging nettle

Overview Plant Description What’s It Made Of? Available Forms How to Take It Precautions Possible Interactions Supporting Research

Stinging nettle (Urtica dioica and the closely related Urtica urens) has a long medicinal history. In medieval Europe, it was used as a diuretic (to rid the body of excess water) and to treat joint pain.

Stinging nettle has fine hairs on the leaves and stems that contain irritating chemicals, which are released when the plant comes in contact with the skin. The hairs, or spines, of the stinging nettle are normally very painful to the touch. When they come into contact with a painful area of the body, however, they can actually decrease the original pain. Scientists think nettle does this by reducing levels of inflammatory chemicals in the body, and by interfering with the way the body transmits pain signals.

General Uses

Stinging nettle has been used for hundreds of years to treat painful muscles and joints, eczema, arthritis, gout, and anemia. Today, many people use it to treat urinary problems during the early stages of an enlarged prostate (called benign prostatic hyperplasia or BPH). It is also used for urinary tract infections, hay fever (allergic rhinitis), or in compresses or creams for treating joint pain, sprains and strains, tendonitis, and insect bites.

Benign Prostatic Hyperplasia (BPH)

Stinging nettle root is used widely in Europe to treat BPH. Studies in people suggest that stinging nettle, in combination with other herbs (especially saw palmetto), may be effective at relieving symptoms such as reduced urinary flow, incomplete emptying of the bladder, post urination dripping, and the constant urge to urinate. These symptoms are caused by the enlarged prostate gland pressing on the urethra (the tube that empties urine from the bladder). Some studies suggest that stinging nettle is comparable to finasteride (a medication commonly prescribed for BPH) in slowing the growth of certain prostate cells. However, unlike finasteride, the herb does not decrease prostate size. Scientists aren’t sure why nettle root reduces symptoms. It may be because it contains chemicals that affect hormones (including testosterone and estrogen), or because it acts directly on prostate cells. It is important to work with a doctor to treat BPH, and to make sure you have a proper diagnosis to rule out prostate cancer.

Osteoarthritis

The leaves and stems of nettle have been used historically to treat arthritis and relieve sore muscles. While studies have been small, they suggest that some people find relief from joint pain by applying nettle leaf topically to the painful area. Other studies show that taking an oral extract of stinging nettle, along with nonsteroidal anti-inflammatory drugs (NSAIDs), helps people reduce their NSAID dose.

Hay fever

One preliminary human study suggested that nettle capsules helped reduce sneezing and itching in people with hay fever. In another study, 57% of patients rated nettles as effective in relieving allergies, and 48% said that nettles were more effective than allergy medications they had used previously. Researchers think that may be due to nettle’s ability to reduce the amount of histamine the body produces in response to an allergen. More studies are needed to confirm nettle’s antihistamine properties. Some doctors recommend taking a freeze-dried preparation of stinging nettle well before hay fever season starts.

Other

Preliminary animal studies indicate that nettle may lower blood sugar and blood pressure. However, more research is needed to determine whether this is also true in humans.

Plant Description

Stinging nettle is the name given to common nettle, garden nettle, and hybrids of these plants. Originally from the colder regions of northern Europe and Asia, this herbaceous shrub grows all over the world today. Stinging nettle grows well in nitrogen-rich soil, blooms between June and September, and usually reaches 2 to 4 feet high.

Stems are upright and rigid. Leaves are heart shaped, finely toothed, and tapered at the ends, and flowers are yellow or pink. The entire plant is covered with tiny stiff hairs, mostly on the underside of the leaves and stem, that release stinging chemicals when touched.

What’s It Made Of?

Stinging nettle products are usually made from the leaves and stems, and sometimes the roots. Root preparations are used to relieve symptoms of BPH.

Available Forms

Stinging nettle is available as dried leaf, freeze-dried leaf, extract, capsules, tablets, and as root tincture (a solution of the herb in alcohol), juice, or tea. It also comes in the form of an ointment or cream that can be applied to the skin. The root appears to have different pharmacological effects than the leaves.

How to Take It

Pediatric

Although stinging nettle is available in many combination formulas to treat colds, asthma, and allergies in children, a specific safe and effective dose for children has not yet been established. Talk to your doctor before giving stinging nettle to a child, so the doctor can determine the proper dose.

Adult

Stinging nettle is used in many forms, including as teas, tinctures, fluid extracts, and creams.

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. However, herbs can trigger side effects, and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care provider.

Stinging nettle is generally considered safe when used as directed. Occasional side effects include mild stomach upset, fluid retention, sweating, diarrhea, and hives or rash (mainly from topical use). It is important to be careful when handling the nettle plant because touching it can cause an allergic rash. Stinging nettle should never be applied to an open wound.

Because nettle can alter the menstrual cycle and may contribute to miscarriage, pregnant women should not use nettle.

DO NOT self treat with nettle for BPH. See your doctor to receive a diagnosis and to rule out prostate cancer.

There is some evidence that stinging nettle may raise blood sugar and interfere with diabetes management. There is also evidence that it can lower blood sugar. Patients with diabetes should monitor their blood sugar closely when using stinging nettle.

Stinging nettle can have a diuretic effect. If you have kidney or bladder issues, speak with your provider.

Possible Interactions

Antiplatelet and anticoagulant drugs (blood thinners)

Stinging nettle may affect the blood’s ability to clot, and could interfere with blood-thinning drugs, including:

  • Warfarin (Coumadin)
  • Clopidogrel (Plavix)
  • Aspirin

Drugs for high blood pressure

Stinging nettle may lower blood pressure, so it could strengthen the effects of these drugs:

Diuretics (water pills)

Because stinging nettle can act as a diuretic, it can increase the effects of these drugs, raising the risk of dehydration:

  • Furosemide (Lasix)
  • Hydrocholorothiazide

Drugs for diabetes

Stinging nettle may lower blood sugar, so it could strengthen the effects of these drugs, raising the risk of hypoglycemia (low blood sugar).

Lithium

Stinging nettle may have a diuretic effect and may reduce the body’s ability to remove this drug.

Nonsteroidal anti-inflammatory drugs (NSAIDs)

In a scientific study of patients with acute arthritis, stewed stinging nettle leaves enhanced the anti-inflammatory effect of diclofenac, an NSAID. Although this effect can reduce pain, talk to your doctor before taking or using stinging nettle if you also take NSAIDs.

Supporting Research

Blumenthal M, Goldberg A, Brinckmann J. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications; 2000:367-375.

Bodemer AA. Urticaria. In: Rakel D, ed. Integrative Medicine. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 70.

Bone K, Mill S, eds. Principles and Practices of Phytotherapy, Modern Herbal Medicine. London: Churchill Livingstone; 2000.

Chrubasik JE, Roufogalis BD, Wagner H, Chrubasik S. A comprehensive review on the stinging nettle effect and efficacy profiles. Part II: urticae radix. Phytomedicine. 2007;14:568-579.

Helms S, Miller A. Natural treatment of chronic rhinosinusitis. Altern Med Rev. 2006;11:196-207.

Johnson TA, Sohn J, Inman WD, Bjeldanes LF, Rayburn K. Lipophilic stinging nettle extracts possess potent antiinflammatory activity, are not cytotoxic and may be superior to traditional tinctures for treating inflammatory disorders. Phytomedicine. 2013; 20:143-147.

Koch E. Extracts from fruits of saw palmetto (Sabal serrulata) and roots of stinging nettle (Urtica dioica): viable alternatives in the medical treatment of benign prostatic hyperplasia and associated lower urinary tract symptoms. Planta Med. 2001;67:489-500.

Konrad L, Muller HH, Lenz C, Laubinger H, Aumuller G, Lichius JJ. Antiproliferative effect on human prostate cancer cells by a stinging nettle root (Urtica dioica) extract. Planta Med. 2000;66:44-47.

Lopatkin NA, Sivkov AV, Medvedev AA, et al. Combined extract of Sabal palm and nettle in the treatment of patients with lower urinary tract symptoms in double blind, placebo-controlled trial. Urologiia. 2006;(2):12, 14-91.

Nahata A. Ameliorative effects of stinging nettle (Urtica dioica) on testosterone-induced prostatic hyperplasia in rats. Andrologia. 2012; 44:396-409.

Pittler MH. Complementary therapies for treating benign prostatic hyperplasia. FACT. 2000;5:255-257.

Popa G, Hagele-Kaddour H, Walther C. Efficacy of a combined Sabal-urtica preparation in the symptomatic treatment of benign prostatic hyperplasia. Results of a placebo-controlled double-blind study. MMW Fortschr Med. 2005;147 Suppl 3:103-108.

Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. J Herb Pharmacother. 2005;5:1-11.

Schneider T, Rubben H. 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. 2004;43:302-306.

Schulze-Tanzil G, de SP, Behnke B, Klingelhoefer S, Scheid A, Shakibaei M. Effects of the antirheumatic remedy hox alpha – a new stinging nettle leaf extract – on matrix metalloproteinases in human chondrocytes in vitro. Histol Histopathol. 2002;17:477-485.

Tarhan O, Alacacioglu A, Somali I, Sipahi H, Zencir M, Oztop I, Dirioz M, Yilmaz U. Complementary-alternative medicine among cancer patients in the western region of Turkey. J BUON. 2009;14:265-269.

Wilt TJ, Ishani A, Rutks I, MacDonald R. Phytotherapy for benign prostatic hyperplasia. Public Health Nutr. 2000;3:459-472.

Review Date: 1/1/2017
Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

While stinging nettle may sound like a dangerous plant, it can be prepared into a supplement with potential benefits against inflammation, allergies, and arthritis. Although it is considered safe, stinging nettles has its risks and side effects as well.

What is Stinging Nettle?

Stinging nettle (Urtica dioica) is an herb native to parts of Europe, Africa, Asia, and North America. Civilizations as old as Ancient Greece used this plant for its medicinal properties, though our modern names for it come from the Anglo-Saxon “noedl” (needle) and the Latin “urtica” (to burn) .

Stinging nettle has been used as a food, fabric, medicine, and cosmetics for thousands of years. Its wide array of uses includes everything from enhancing male health to easing nasal congestion .

Touching the leaves of a wild stinging nettle can cause skin irritation. However, when processed for consumption, the nettle’s stinging hairs are crushed, cooked, or boiled in a way that eliminates their stinging abilities and makes them safe for consumption .

Stinging nettle is a spiny, irritating herb that has been used for food, fabric, medicine, and cosmetics for thousands of years. It must be processed, with the spines removed, to be safe for consumption.

Snapshot of Stinging Nettle

Proponents:

  • Reduces arthritis pain
  • May relieve benign prostatic hyperplasia
  • May decrease blood pressure and blood sugar
  • Reduces inflammation
  • Other possible benefits for testosterone, water retention, and healing

Skeptics:

  • Stinging spines may cause a rash
  • Rare allergic reactions to raw juice or purée
  • May have dangerous drug interactions
  • May worsen conditions with too much testosterone

Components

Bioactive Compounds of Leaves

Stinging nettle contains multiple bioactive compounds responsible for its health and antioxidant effects. These include :

  • Quercetin, an antioxidant and anti-diabetic compound
  • Rutin, closely related to quercetin
  • Kaempferol, a potent anti-inflammatory compound
  • Quinic acid, an antioxidant and anti-inflammatory compound
  • Caffeic acid, another strong antioxidant
  • Choline, a vital nutrient with anti-inflammatory properties
  • Lecithin, a healthy fat that may help reduce cholesterol

Bioactive Compounds of Root

Stinging nettle root has a significantly different chemical profile than the leaves, with about half the quinic acid and almost no caffeic acid by comparison. However, the roots also contain some compounds not found in the leaves, such as fatty acids, plant sterols, secoisolariciresinol, vanillin, and scopoletin .

The compounds in nettle root may protect against heart disease, affect the brain, and reduce cholesterol. The root is also particularly effective against benign prostatic hyperplasia .

Nutritional Value

Fresh stinging nettle plants contains many valuable vitamins and nutrients, including provitamin A, vitamin B1, vitamin K, potassium, calcium, and iron. It also contains oxalates, which will bind to these minerals and reduce their absorption .

Stinging nettle is rich in nutrients, antioxidants, and other active compounds. Its roots and leaves have significantly different chemical profiles from one another.

Mechanism of Action

Stinging nettle is an antioxidant: it blocks the oxidation of fats, linoleic acid, deoxyribose, and muscle proteins, thereby protecting many tissues from oxidative stress .

Stinging nettle reduces inflammatory cytokine release and reduces inflammatory biomarkers like TNF-a, IL-1, IL-6, and hs-CRP. It also interferes with the way the body sends pain signals and decreases the sensation of pain .

These anti-inflammatory effects appear to also help allergies, reduce nasal congestion, help with arthritis, and more .

Why Touching a Wild Nettle Hurts

If you see a stinging nettle plant growing wild, don’t touch it without gloves! Nettle leaves and stems are covered with tiny, stinging hairs called trichomes, which will pierce your skin and inject an irritating fluid containing formic acid, histamine, acetylcholine, and serotonin. Histamine is an inflammatory compound that will make your skin red and irritated, and formic acid is the chemical that causes pain from ant and bee stings .

Proper preparation of stinging nettle leaves deactivates the formic acid. A high-quality stinging nettle leaf product will not contain anywhere near enough formic acid to cause concern .

The spines of stinging nettle contain formic acid, histamine, acetylcholine, and serotonin, which together cause pain and inflammation on contact with skin.

Health Benefits of Stinging Nettle

Stinging nettle supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.

Possibly Effective For

1) Arthritis and Pain

Stinging nettle’s anti-inflammatory properties could potentially help relieve arthritis symptoms. A combination of stinging nettle leaf extract and devil’s claw significantly reduced symptoms of arthritis compared to a placebo in a 12-week study of 92 arthritis patients .

These arthritis-relieving properties may be due to nettle’s ability to inhibit the activation of a protein called NF-κB, which would otherwise increase the production of inflammatory compounds. NF-κB is often overactive in people with arthritis .

Stinging nettle is often used by traditional practitioners. Urtication, also known as ‘flogging with nettles,’ is a technique where users apply raw, unprocessed stinging nettle leaves or stems to the body to generate inflammation. This has been used since Ancient Roman times for relieving chronic rheumatism, but researchers have only just begun to investigate its effectiveness .

There is also evidence that using stinging nettle leaves topically can help relieve pain in those with:

  • Lower back pain
  • Thumb pain
  • Knee pain

A traditional practice called urtication, by which people rub raw stinging nettle leaves onto their skin to relieve rheumatic pain. Clinical studies have found evidence that this process could work.

Insufficient Evidence For

The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of stinging nettle for any of the below-listed uses. Remember to speak with a doctor before using stinging nettle, and never use it in place of something your doctor recommends or prescribes.

2) Allergies (Hay Fever)

Taking stinging nettle leaf extracts help decrease allergies. Scientists believe this may be due to the plant’s ability to reduce histamine production and inflammatory markers.

Both freeze-dried nettle leaves and nettle tea may also help with nasal allergies and allergic reactions .

In one study, 57% of patients were said to have rated nettle as ‘effective’ in helping allergies, with 48% even saying nettle was more effective than allergy medications they had used previously .

However, stinging nettle also contains histamine – especially the leaves and hairs. More research is required to fully understand how this plant can reduce mast cell activation despite containing histamine. Many of its other bioactive compounds likely act together to achieve an altogether allergy-relieving effect .

Stinging nettle leaf extract and tea have been found to reduce allergic reactions.

3) Benign Prostatic Hyperplasia (BPH)

Benign prostatic hyperplasia (BPH) is a condition wherein the prostate gland becomes enlarged, usually due to age. This can cause difficulty urinating and various other symptoms, including sexual dysfunction .

Stinging nettle root extracts are among the most popular herbal remedies used to ease the symptoms of enlarged prostates, though the evidence is still considered insufficient for medical use .

A review of several studies showed that stinging nettle root extract effectively improves the symptoms of an enlarged prostate, with a low risk of negative effects or toxicity .

In a study of 246 BPH patients, a special extract of stinging nettle safely and effectively reduced the adverse effects of prostate enlargement when compared to placebo .

In another 6-month study of 558 people, stinging nettle roots significantly improved multiple measures of prostate health, including :

  • Relief of lower urinary tract
  • Maximum urinary flow rate
  • Residual urine volume
  • Prostate size
  • International Prostate Symptom Score

Another study combined stinging nettle and saw palmetto extract. It was as effective as and better tolerated than the prescription drug finasteride, which is used to treat enlarged prostates .

The inhibiting effects of stinging nettle root extracts were also demonstrated in rats and mice with induced large prostates .

Note that stinging nettle root has been significantly more effective than leaf or stem in studies of people with BPH. This may be due to high lignan content, which the leaves don’t contain.

Larger and more robust studies with standardized extracts and preparations will be required to determine the role of stinging nettle in BPH.

Stinging nettle root extracts have emerged as a promising remedy for benign prostatic hyperplasia, though additional research is required before it can be broadly recommended.

4) Blood Sugar

Stinging nettle leaves and stems – but not roots – may help decrease blood sugar. Chemicals in nettle leaves appear to trigger the release of insulin and other compounds that reduce blood sugar .

In a study of 92 subjects, stinging nettle extract decreased fasting blood sugar levels and other blood sugar levels when compared with the placebo .

Stinging nettle also decreased blood sugar and increased insulin in rat studies .

A leaf extract of stinging nettle improved blood sugar balance in mice and helped with insulin resistance, which delayed the onset of type 2 diabetes .

Stinging nettle leaf and stem extracts have decreased blood sugar in small human studies.

5) Inflammation

In a study of 37 arthritis patients, combining stinging nettle tea with diclofenac (a non-steroidal anti-inflammatory drug or NSAID) enhanced the drug’s anti-inflammatory effects .

In mouse immune cells (macrophages), stinging nettle extract was as effective at reducing inflammation as celastrol from thunder god vine. Both were powerful antioxidants and anti-inflammatories .

Nettle also inhibited human leukocyte elastase, which is known to increase inflammation .

Stinging nettle leaf extracts contain active compounds that block inflammatory markers. In one human study, stinging nettle and an NSAID reduced inflammation more than the NSAID alone.

Animal & Cell Research (Lacking Evidence)

No clinical evidence supports the use of stinging nettle for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.

6) Free Testosterone

Free testosterone is the available blood testosterone, not bound to sex hormone binding globulin, or SHBG. The less testosterone that’s bound to SHBG, the more free testosterone is available for the body to use. Testosterone bound to SHBG is unusable to the body .

Stinging nettle roots contain substances called ligans, which bind to SHBG. This reduces the amount of SHBG that can bind testosterone; hence, while nettle does not increase total testosterone in the blood, it may increase available testosterone. Bodybuilders have traditionally used similar plant substances to increase free testosterone .

Multiple cell studies have shown that lignans from stinging nettle roots reduced SHBG binding to testosterone .

There is also evidence that stinging nettle blocks the conversion of testosterone into estrogen, an effect that may be increased with the addition of saw palmetto. This combination appears to act on an enzyme called aromatase, which converts testosterone to estrogen, but does not affect testosterone receptors .

While stinging nettle is a popular supplement for boosting testosterone, there is currently nowhere near enough research to confirm this benefit. Future human studies will tell us more.

7) Blood Pressure

Stinging nettle stems and leaves may reduce blood pressure, but they could also increase the risk of blood pressure dropping too low. In rats, stinging nettle lowered blood pressure by increasing the amount of salt that the kidneys filtered out of the blood .

Stinging nettle can also lower blood pressure by triggering the release of nitric oxide, which causes blood vessels to widen .

In animals, stinging nettle has reduced blood pressure by multiple mechanisms.

8) Water Retention

Diuretics, sometimes called water pills, are medications that increase urine production. They can help remove excess sodium and water from the body. In animal studies, stinging nettle increased urine flow and acted as a diuretic .

Proper use of diuretics can help with various health complications by :

  • Decreasing blood pressure
  • Compensating for poor kidney function
  • Reducing bloating

9) Wound Healing

In rats, stinging nettle leaf extracts improved the quality of healing of second-degree burns in rats when applied to their skin. It accelerated healing and reduced scarring more effectively than conventional methods (vaseline and silver sulfadiazine) .

A very limited human study of eight experimental burns using a gel with stinging nettle leaf extracts with arnica extracts seems to support this benefit .

Limitations and Caveats

Although there is a large body of promising research, caution should always be used when extrapolated the results of animal studies to humans. Also, as with any supplement, care should be used in taking it.

A few studies have demonstrated that different parts of the stinging nettle plant contain different chemical compounds and may have completely different effects. Some research that claims that nettle extracts either do or do not have certain benefits may not have investigated each part of the plant, each extract, or even the ideal extract for the job.

Side Effects & Safety

Although certain applications require the leaves to be applied directly to the skin, we do not recommend touching a wild stinging nettle with your bare hands. The formic acid and histamine in the sharp “hairs” on the nettle’s surface will likely cause a red, lumpy rash. In addition, some people may experience an allergic reaction to raw puréed nettle or nettle juice .

Stinging nettle may increase free testosterone and may, therefore, worsen any health conditions characterized by too much testosterone, such as polycystic ovarian syndrome (PCOS) .

Due to possible contractions of the uterus, stinging nettle may be unsafe to take during pregnancy. Contractions of the uterus can cause a miscarriage or cause women to go into early labor. There are no available studies about the effects of stinging nettle on nursing infants, so it is recommended to consult your doctor if you are considering taking it while breastfeeding .

Stinging nettle is sometimes used to increase milk production in nursing mothers, but no safety data exists; we therefore caution against using stinging nettle while breastfeeding .

Drug Interactions

Combining stinging nettle with hypertension and diabetes drugs may cause your blood pressure and blood sugar to become too low .

The active compounds in stinging nettle may block metabolic enzymes in the CYP1A family, thereby increasing the effects of any drugs broken down by these enzymes. In rats, this effect has been demonstrated with melatonin; other drugs that may be affected include caffeine, warfarin, and many others .

By the same token, stinging nettle can increase the beneficial effects of non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil) and naproxen (Aleve) .

Talk to your doctor before supplementing with stinging nettle to prevent adverse events or unexpected interactions.

Supplementation & Dosage

Forms of Stinging Nettle

Stinging nettle is usually available in the following forms:

  • Tea
  • Capsules (leaf or root extract)
  • Tinctures (extract dissolved in alcohol)
  • Loose leaves
  • Dried roots
  • Cream or gel (for arthritis and pain)

If collected and processed carefully, wild stinging nettle can also be gathered and cooked into many recipes. Look for instructions from experts before attempting to harvest nettle yourself.

Always check the label to make sure which part of the plant was used to make a given product.

Dosage

There is no safe and effective dose of stinging nettle for any medical purpose because no sufficiently powerful study has been conducted to find one. That being said, many studies have found an association between certain doses of nettle and beneficial effects.

A dosage of 450 mg of dry stinging nettle root extract per day is associated with beneficial effects for benign prostatic hyperplasia. Many commercial root supplements come in 250 mg or 500 mg capsules .

Increasing free testosterone is dose-dependent. A root tincture with a concentration of 0.6 mg/ml significantly blocked testosterone binding to SHBG; at a concentration of 10 mg/ml, binding was inhibited completely .

Commercial leaf extracts sometimes come with recommendations of between 275 mg and 2 g of their product per day; note that the quality and content of these extracts is likely variable. Raw stinging nettle leaf, cut from the live plant, significantly reduces pain when applied to directly to an arthritic joint for thirty seconds, once per day .

Takeaway

Stinging nettle is a common plant that grows all over the world. People have used it to treat rheumatism and pain for thousands of years, and more recent research shows that it may reduce inflammation, relieve allergies, increase free testosterone, reduce blood sugar and pressure, act as a diuretic, and improve wound healing.

It is generally considered safe, though the fresh leaves and stem of the plant can cause a nasty, stinging rash when touched. True allergy to stinging nettle is rare, but possible. This supplement may increase the effect of NSAIDs and other drugs; caution is advised when combining stinging nettle with medication.

Stinging nettle is available in many forms, including loose leaf, capsules, tincture, root, tea, cream, or live (often wild) plant. Researchers do not agree on an effective dosage for all people, conditions, or parts of the plant.

Why do people take stinging nettle?

People take stinging nettle to try to treat health problems, including:

Benign prostatic hyperplasia (BPH). Stinging nettle root is a common treatment in Europe for symptoms of BPH. This is a noncancerous condition that causes the prostate gland to enlarge, making urination difficult.

Some research shows that stinging nettle root may be helpful in treating this problem. Experts are not sure which components in the plant may have an effect on BPH, if any. More research is needed to show that the treatment is indeed effective.

Allergies. Stinging nettle leaf may be useful in reducing the symptoms of hay fever by acting as an anti-inflammatory. Some research has linked treatment with stinging nettle leaf to relief of symptoms such as sneezing, runny nose, and itchy eyes. But more well-designed studies are needed to confirm this effect.

Joint pain. Research has found some evidence that rubbing stinging nettle leaves on painful joints can provide pain relief. One small study also found that eating stewed nettle leaves was a helpful addition to the anti-inflammatory drug diclofenac.

People have also used stinging nettle as a diuretic — a treatment that causes the body to shed more water in the urine. Research has found this effect from stinging nettle in rats.

Optimal doses of stinging nettle have not been set for any condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it hard to set a standard dose.

Trial 1

The effects of nettle as a possible local painkiller were examined in 27 people with osteoarthritis-related pain at the base of their thumb. Participants were told that the study was testing two types of nettle leaf but were randomly given either a nettle leaf or a placebo leaf to apply to the painful area daily for one week. Participants continued on their usual treatment during this period. They then stopped using the leaf for five weeks and used the other leaf for one week afterwards.

  • Participants using nettle leaves reported less pain and disability compared to those who used the placebo leaves.
  • The difference in pain reduction remained significant during the first week following treatment and then disappeared gradually thereafter.

Trial 2

The potential beneficial effects of stinging nettle were examined in 42 people with osteoarthritis of the knee. Participants were randomly allocated to apply either stinging nettle or another type of nettle (which isn’t thought to treat osteoarthritis) to their knees for one week.

  • Participants in both groups had a similar mild but insignificant reduction in pain scores.
  • Those using stinging nettle had only minor and short-term skin irritation.

Stinging nettle sounds like a plant to be avoided (and it can give a nasty sting or rash when the fresh leaves brush up against skin). But despite its name, nettle has many health benefits and is one of the most widely used plants in herbal medicine.

Used for everything from anemia to skin problems to rheumatism, nettle is a very benevolent and safe herb to use once the ‘stingers’ are taken care of. It also makes a very nourishing and revitalizing tea.

Here’s more about the surprising benefits of nettle leaf, plus how to use it for your health.

Origins
It’s very common to find stinging nettle growing in the wild across the U.S., Canada, and many other countries. Nettle has its origin in the colder regions of Europe and Asia, and its medicinal use dates back to the ancient Greek and Roman civilizations.

Fresh nettle can easily be gathered in the spring or fall by looking for it in semi-shaded areas, especially close to stream banks and other moist, fertile spots. Be sure to wear gloves when harvesting it fresh to avoid getting the typical stinging nettle rash.

Nourishing for the Body
Many of nettle’s benefits come from its high nutrient content. It contains vitamin A, vitamin C, and vitamin K along with easily assimilated calcium and iron. Other nutrients include magnesium, potassium, protein, beta-carotene, and chlorophyll.

Stinging nettle also has a high antioxidant content and contains polyphenols. Antioxidants help to defend the body against free radicals which can cause aging, some types of cancer, and other diseases. (1)

Research on polyphenols is showing that they may help to prevent and manage inflammatory diseases such as certain types of cancer, heart disease, and diabetes. (2)

The range of nutrients in nettle can also be helpful for anyone recovering from prolonged sickness or stress, and the iron content is easily digestible for those with anemia. (3)

Nettle Benefits for Women’s Health
The nutrients and compounds in stinging nettle are especially beneficial for women through all stages of life. Nettle can increase the overall health of the female reproductive system and is often used in blends for PMS, fertility, and menopause. (Gladstar. Medicinal Herbs: A Beginner’s Guide, pg. 176)

The nourishment of nettle can also help with fatigue that comes from iron-deficiency related to a heavy menstrual cycle as well as supporting mother and child during pregnancy. It can also help to enrich breastmilk for nursing mothers. (3)

Seasonal Allergy Relief
While studies are still ongoing, there is some evidence that stinging nettle can help to provide relief for seasonal allergies and hay fever. This seems to be due to its anti-inflammatory effects which can help with allergy symptoms. (4)

In one study, using freeze-dried nettle for hay fever was found to be more effective than the placebo. (5) Although more studies are needed to determine how nettle may help with allergies, herbalists have been using nettle to deal with seasonal allergies for many years.

The Herbal Academy recommends using a nettle tincture or freeze-dried capsules one or two months before the allergy season begins and continuing until it ends. (3)

Help for Pain and Arthritis
The anti-inflammatory compounds within nettle also show promise for helping with osteoarthritis, gout, and joint pain caused by inflammation. (5)

One study showed that applying a stinging nettle cream to an area of the body affected by osteoarthritis was significantly more effective than the placebo. (6) Nettle also seems to work against inflammation and pain when taken internally. A supplement containing nettle, fish oil, and vitamin E significantly reduced arthritis pain, and participants felt like they could reduce their dosages of pain relievers. (7)

Adrenal Fatigue
Along with all the other benefits, the high nutrient content of nettle can also help with recovery from prolonged stress and adrenal fatigue.

With its full spectrum of easily assimilated vitamins and minerals, an infusion made from the leaves can help the body and adrenals recover from fatigue. It can also provide extra nutrients during pregnancy and lactation. (3)

Side Effects
Apart from its stinging leaves, nettle is a very safe herb that typically does not have any side effects. Once the leaves are heated or dried, the formic acid (which causes the sting/rash) is destroyed.

Stinging nettle may have a diuretic effect. Speak with your doctor before using if you take blood thinners, blood pressure medication, diuretics, or diabetes medication.

Ways to Use Nettle
Nettle is available in various forms including the fresh leaves, dried/freeze-dried leaves, capsules, tinctures, extracts, and creams.

Nettle Tea: One of the best and easiest ways to use nettle is to make an infusion (a strong tea) using the dried leaf. Simply steep 1-3 tablespoons of dried nettle leaf in 1 cup of water for 4-8 hours. After it’s done steeping, strain out the herb and add honey or maple syrup to taste. Make a large batch if you know you want to keep drinking the tea throughout the day. It can be stored in the refrigerator for up to 2 days.

Cooked Nettle: Nettle is considered to be a medicinal food, which means that it can be cooked and eaten in recipes or as its own dish. The whole plant is edible, but most often it’s the fresh leaves that are harvested and steamed. (Once cooked, the leaves lose their sting.) Season the steamed nettle with lemon juice and herbs or add it into soups and recipes in place of spinach or other greens.

Using Nettle with Other Herbs
Nettle is often combined with other herbs like green oat tops, raspberry leaf, and alfalfa leaf. These blends can be even more beneficial for the body because of the combination of different herbs and compounds.

Adrenal Love Tea combines nettle leaf with adaptogenic herbs to help the body recover from stress and adrenal fatigue. Womb Wellness Tea contains nettle, alfalfa, raspberry leaf, and other herbs that work to nourish the womb.

To restore iron levels during pregnancy or after heavy menstrual cycles, the Iron Tonic Tea is a blend of nettle and other iron-containing herbs to strengthen the body. For allergy and immune support, ImmuniTea is thoughtfully blended with elderberry, echinacea leaf, astragalus root, and lemon balm leaf.

Discover the Benefits of Nettle Leaf
Nettle leaf is a very nourishing and nutrient-rich herb that is also readily available both in the wild and in its dried form. Whether for fatigue, seasonal allergies, or to help with inflammation, nettle has been used for many years and is still popular with herbalists today.

Try it in an infusion, as food, in capsule form, or in a nourishing tea blend. You’ll be glad you did!

Health benefits take the sting out of nettles

DOES IT WORK?:Nettles are a good source of vitamins, writes DÓNAL O’MATHÚNA

IF YOU RUB UP against nettles these days, you’re likely to curse their very existence. The stinging pain and welts they cause have led to their Latin name ( Urtica) being used for any similar skin irritation: urticaria.

Yet down through history, many have been thankful for the various ways in which nettles could be used. In ancient times, nettles were woven into fabric.

More recently, nettles have been used to make soups and eaten as a vegetable. They are as nutritious as spinach and other greens, being rich in vitamin C, vitamin K, carotene, potassium and calcium.

In the 19th century, a nettle tonic was believed to promote hair growth. The most likely reason for this was a belief that whatever caused the growth of the tiny hairs on nettle leaves would do likewise for human scalps.

Fresh leaves have been used on arthritic joints as a counter irritant. The idea here is that arthritic pain might be relieved by causing another irritation close to the joint. The leaves also are believed to contain anti-inflammatory agents.

While stories abound of people reporting success with such approaches, little research has been conducted in the area.

Extracts of nettle leaves and roots have had numerous medicinal uses. Probably the oldest application is as a diuretic, where nettle juice was used to increase urinary output, especially for those with symptoms of heart failure or high blood pressure.

Nettles also have been used in various parts of the world to treat asthma, allergies, coughs, kidney problems, rheumatism and prostate difficulties.

Some modern pharmaceuticals have been criticised as drugs looking for a disease to treat. They may be widely used, but their effectiveness for any one condition is questionable.

In a similar way, nettles have been used for many different conditions, but questions remain about their effectiveness in treating any particular condition. Few of the specific uses have been tested in well-controlled trials.

However, two applications have received more study than most, and point to different potential uses of the leaves and the roots.

Extracts of nettle leaves contain a number of compounds that are chemically related to caffeine. Several small studies have found diuretic effects after people used such extracts.

However, most of these studies were uncontrolled and poorly designed. The results were encouraging, although they did not demonstrate a large beneficial effect.

Extracts of nettle roots have received significantly more research, although for a different use.

Benign prostatic hyperplasia (BPH) is a condition in men which causes difficulties with urination along with frequent urges to urinate, especially at night.

Pharmaceutical drugs are available, but have adverse effects. Saw palmetto is a herb used to treat BPH, and nettle root extract has also been recommended. Several uncontrolled studies of nettle root for BPH have been conducted, along with six randomised controlled trials.

Overall, the results have indicated some beneficial effects, although the improvements were relatively small in scale. One study of a combined nettle root and saw palmetto product showed a somewhat larger effect.

Although nettles are highly irritating when encountered in the wild, they have few side effects when taken medicinally or when cooked and eaten. Some people can be allergic to nettles, and others get gastrointestinal irritation after taking the remedies.

Nettles are a highly nutritious food and a good source of vitamins and nutrients. Although they have a long and varied history as medicinal agents, few specific benefits have been clearly demonstrated.

Another difficulty in evaluating nettle remedies arises from the many different ways in which extracts have been made.

The most promising areas deserving further research are nettle leaves as diuretics and nettle root extracts for BPH. Although neither application is strongly supported by current evidence, the results so far have been encouraging.

  • Dónal OMathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, Dublin City University. He is author of Alternative Medicine: The Christian Handbook, Updated and Expanded Edition, Zondervan, 2007

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