What Is Nettle Tea Good For? Benefits, Allergies, Evidence and Cautions

Strong = multiple human trials or a meta-analysis. Moderate = a few small trials. Preliminary = early, traditional or animal data.

1. 1

   Eases hay fever and allergy symptoms

   Moderate evidence

   In the best-known trial, 98 people with allergic rhinitis took 300 mg of freeze-dried nettle leaf or placebo twice a day for one week during pollen season. On global assessment 58% of the nettle group rated it moderately or highly effective against 37% on placebo, with sneezing and itchy eyes improving most, but diary scores were only marginally better than placebo. A 2017 trial of 150 mg nettle root extract a day for one month found both groups improved with no significant difference. Nettle appears to block histamine H1 receptors and mast-cell tryptase in the lab, so the mechanism is plausible, but expect a mild effect, not antihistamine-level relief.

   Key evidenceMittman P, Planta Medica 1990; randomised, double-blind, 69 completers

2. 2

   Helps lower blood sugar in type 2 diabetes

   Moderate evidence

   A randomised, double-blind trial gave 50 people with advanced type 2 diabetes 500 mg of nettle leaf extract or placebo every 8 hours alongside their usual drugs for 3 months. The nettle group had significantly lower fasting glucose, 2-hour post-meal glucose and HbA1c than placebo, with no change in liver or kidney tests. A separate 8-week trial in 46 diabetics reported lower fasting glucose and inflammatory markers. These are capsule doses of concentrated extract; two or three cups of leaf tea deliver less, so treat the tea as a possible helper, and watch for lows if you use insulin or sulfonylureas.

   Key evidenceKianbakht et al., Clinical Laboratory 2013; 3-month placebo-controlled RCT

3. 3

   Mild diuretic that flushes the urinary tract

   Moderate evidence

   The European Medicines Agency's herbal monograph lists nettle leaf as a traditional medicine 'to increase the amount of urine to achieve flushing of the urinary tract' as an adjunct in minor urinary complaints, at 2 to 4 g of dried leaf in tea up to three times a day. The grade reflects long, well-documented traditional use plus animal data showing increased urine and sodium output, rather than a modern placebo-controlled trial in people. The effect is gentle and, because the leaf is rich in potassium, less depleting than a drug diuretic.

   Key evidenceEMA Committee on Herbal Medicinal Products, Urticae folium monograph 2010

4. 4

   Supplies calcium, iron, magnesium and vitamin K

   Moderate evidence

   Blanched nettle leaves contain roughly 480 mg of calcium, 1.6 mg of iron and 57 mg of magnesium per 100 g, along with high vitamin K and carotenoids, which is why nettle is treated as a nourishing 'food herb'. Only a fraction of minerals move into water: steeping 2 g of leaf for 10 minutes extracts tens of milligrams of calcium and magnesium, meaningful but far from a supplement dose, and a long overnight infusion of a handful of leaf extracts more. The iron is non-haem and nettle's tannins limit its uptake, so the tea is not a treatment for anaemia.

5. 5

   Relieves joint pain and inflammation

   Preliminary evidence

   Nettle is a traditional remedy for arthritis, and the EMA monograph also lists the leaf for 'minor articular pain'. Lab studies show nettle leaf extract inhibits NF-kB signalling and the inflammatory cytokines TNF-alpha and IL-1beta. The only randomised human trial (27 patients with base-of-thumb osteoarthritis) applied fresh stinging leaf to the skin daily for a week and found pain and disability scores fell significantly compared with a non-stinging control plant. That tells you nothing direct about tea, so the oral claim remains tradition plus mechanism.

   Key evidenceRandall et al., Journal of the Royal Society of Medicine 2000 (topical nettle)

6. 6

   May lower blood pressure

   Preliminary evidence

   In rats, nettle leaf extract lowered blood pressure by relaxing arteries through nitric oxide release, opening potassium channels and increasing urine output, with heart rate and cardiac output also falling at higher doses. No controlled human trial has tested nettle tea for hypertension. The practical point is additive: if you already take blood pressure medicines, nettle tea could push you slightly lower, so stand up slowly and mention it to your prescriber if you drink it daily.

   Key evidenceQayyum et al., BMC Complementary and Alternative Medicine 2016 (rat study)

7. 7

   Supports prostate and urinary symptoms (root, not leaf)

   Preliminary evidence

   This belongs here mainly to avoid confusion. In a 6-month trial of 620 men with benign prostatic hyperplasia, nettle root extract improved urinary symptom scores and flow more than placebo, and root is often combined with saw palmetto for the same purpose. Those studies used root extracts at 120 to 360 mg a day; the leaf tea covered on this page has no prostate evidence of its own, so men with prostate symptoms should look at nettle root rather than drinking more leaf tea.

   Key evidenceSafarinejad MR, Journal of Herbal Pharmacotherapy 2005; 620 men, 6 months

Is nettle tea good for you?

• Yes, for most adults nettle tea is a safe, caffeine-free, mineral-rich drink with small but real evidence for hay fever and blood sugar, and a gentle diuretic effect.
• The benefits are modest; it will not replace an antihistamine during peak pollen or a diabetes medicine, and the prostate evidence belongs to the root, not the tea.
• Limit or avoid it if you take warfarin (vitamin K), diuretics, lithium, blood pressure or diabetes medicines, or if you have kidney disease or heart failure with fluid restrictions.
• Avoid it in pregnancy; traditional sources warn of uterine stimulation and there are no safety trials. Ask a clinician before using it while breastfeeding.
• Pick dried leaf from a reputable supplier or harvest young spring tops with gloves; older leaves after flowering form gritty cystoliths that can irritate the urinary tract.

• Longer steeps pull out more minerals but also more tannin; a squeeze of lemon and a little honey balance it.
• Fresh nettle must be cooked, dried or thoroughly wilted; the sting is destroyed by heat within seconds.
• Blend with peppermint for hay fever season; both are caffeine-free and the mint masks nettle's grassy edge.

Frequently asked questions

1. Mittman P. Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis. Planta Medica (1990)
2. Bakhshaee M, Mohammad Pour AH, Esmaeili M, et al.. Efficacy of supportive therapy of allergic rhinitis by stinging nettle (Urtica dioica) root extract: a randomized, double-blind, placebo-controlled clinical trial. Iranian Journal of Pharmaceutical Research (2017)
3. Kianbakht S, Khalighi-Sigaroodi F, Dabaghian FH. Improved glycemic control in patients with advanced type 2 diabetes mellitus taking Urtica dioica leaf extract: a randomized double-blind placebo-controlled clinical trial. Clinical Laboratory (2013)
4. Randall C, Randall H, Dobbs F, Hutton C, Sanders H. Randomized controlled trial of nettle sting for treatment of base-of-thumb pain. Journal of the Royal Society of Medicine (2000)
5. Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. Journal of Herbal Pharmacotherapy (2005)
6. Qayyum R, Qamar HM, Khan S, et al.. Mechanisms behind the antihypertensive properties of Urtica dioica L.. BMC Complementary and Alternative Medicine (2016)
7. Community herbal monograph on Urtica dioica L., Urtica urens L., folium. European Medicines Agency, Committee on Herbal Medicinal Products (2010)
8. Roschek B Jr, Fink RC, McMichael M, Alberte RS. Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis. Phytotherapy Research (2009)
9. Stinging Nettle. MedlinePlus Herbs and SupplementsView source