What is Nettle?

Nettle (Urtica dioica) is a common wild plant with toothed leaves and stinging hairs. The leaf, the root and the seed are all used. Cooked or dried leaf is also eaten as a food.

In American folk and Eclectic practice, the leaf was used as a spring tonic and a mild diuretic (water pill). The root came into wide use later, for older men with urinary trouble.

Here is the short verdict. Nettle root may slightly ease the urinary symptoms of an enlarged prostate, but the trials are small and mixed. Most other uses rest on tradition, and tradition is not proof that something works or that it is safe.

How does Nettle work?

No one has shown clearly how nettle works in the body. The claims below come mostly from lab and animal work.

In cell and animal studies, nettle root extracts appear to act on enzymes and proteins that handle testosterone. Whether that happens in men who swallow a capsule is not settled.

In test tubes, nettle leaf compounds appear to damp down signals that drive swelling and pain. This has not been confirmed in people.

The leaf's old name as a water pill suggests it makes you pass more urine. Human proof for that is weak.

The sting itself is better understood. Fresh hairs inject histamine and other irritants, which is why the skin burns and welts.

What forms does Nettle come in?

Nettle is sold in many forms. The plant part matters more than the form you pick.

Dried leaf tea, loose or in bags.

Leaf capsules and tablets.

Freeze-dried leaf capsules, sold for hay fever.

Root capsules, tablets and tinctures, usually sold for prostate symptoms.

Liquid extracts and tinctures in alcohol.

Creams and oils for rubbing on sore joints.

Young shoots, cooked as a green like spinach.

Labels often blur leaf and root. Check which part is in the bottle. A product aimed at prostate symptoms should say root.

Where it comes from:

Nettle has a long record in European folk use. American Eclectic doctors of the 1800s carried that use over.

They gave the leaf as a spring tonic and for what they called thin or poor blood. Eclectic texts also list it for bleeding, gout and skin complaints.

Some old practitioners beat stiff joints with fresh stems on purpose. The practice had a name, urtication. It was painful and is not something to copy at home.

Nettle was also a food and a fibre plant. People ate it in lean years and spun it into cloth.

What does Nettle help with?

• Urinary symptoms of an enlarged prostate (BPH): This is the best studied use, and the evidence is still only fair. Folk use gave the root to older men who got up at night to pass water. Several trials of nettle root, alone or with saw palmetto, report small gains in symptom scores. Many were short or funded by makers. The size of the benefit looks modest. Nettle is not shown to shrink the prostate. It does nothing for prostate cancer. Get urinary symptoms checked by a doctor before you treat them yourself.
• Hay fever and allergy symptoms: This use is popular but poorly supported. Freeze-dried leaf was promoted for sneezing, itchy eyes and a runny nose. One small trial from 1990 hinted at a slight edge over a dummy pill. Later work has been small and weak. For now this stays unproven.
• Joint pain and osteoarthritis (wear-and-tear arthritis): Evidence here is thin. Eclectic practice used stings and leaf poultices on stiff, aching joints. Small trials of nettle cream, and of leaf taken with a low dose anti-inflammatory drug, suggest mild relief. The studies are few, short and small. They do not show that nettle protects the joint.
• Mild fluid retention: Nettle leaf was a classic folk water pill. Human evidence for this effect is very thin. Swelling can be a sign of heart, kidney or liver trouble. Do not treat it with nettle. See a doctor instead.
• Blood sugar in type 2 diabetes: Some small trials report modest drops in blood sugar with nettle leaf. The results are not consistent and the groups were small. Nettle is not a replacement for diabetes treatment. If you take insulin or other diabetes drugs, adding nettle can push your sugar too low.
• Mineral-rich food green: This one is simply food, not treatment. Cooked nettle greens supply iron, calcium, magnesium and vitamin K, much like other dark leaves. Tea gives far less than cooked greens. Nettle is not a proven treatment for low iron (anaemia). A blood test and proper iron treatment are the right route for that.

Which foods are rich in Nettle?

1. Young nettle shoots, cooked as a green
2. Nettle soup
3. Nettle leaf tea
4. Nettle beer and cordials
5. Cheeses wrapped in nettle leaf

Practical Tips:

Nettle is an ordinary food in many parts of Europe. Cooking or drying kills the sting, so cooked greens do not burn.

Food amounts are small and generally safe for most healthy adults. The same warnings still apply if you take warfarin, lithium or diabetes drugs.

What are the side effects of Nettle?

• Mild stomach upset or nausea
• Loose stools
• Passing urine more often
• Sweating
• Skin rash or itch
• Burning, raised rash from touching the fresh plant
• Blood sugar lower than expected in people on diabetes drugs
• Allergic reaction, which is rare

Good to know:

Most side effects are mild and settle when you stop. Stomach upset and extra trips to the toilet are the usual complaints.

True allergic reactions are rare but real. Swelling of the lips or throat, hives or trouble breathing is an emergency.

The sting from the fresh plant is common and usually harmless. It can still be nasty on a child or on broken skin.

How much Nettle should you take?

• Recommended daily: This page does not set a dose for you. What follows is the kind of figure printed on labels and used in trials. Leaf tea labels often list about 2 to 4 grams of dried leaf per cup. Leaf capsules often list 300 to 500 mg, once or twice a day. Root products for prostate symptoms often list 300 to 600 mg of extract a day. Trials have used roughly that range. These are label figures, not advice for you. The right amount depends on your age, your health and your other drugs. Ask a pharmacist or doctor before you start.
• Best time of day: Time of day matters little for most uses. Leaf products may make you pass more urine, so some people skip them late at night. Root labels often split the amount into morning and evening. Either pattern is fine for most people.
• With or without food: Either way works. Capsules taken with food may cause less stomach upset. Tea is often drunk between meals. Drink enough water, since the leaf may make you pass more urine.
• Time to effect: Expect slow change, if any. Prostate symptom trials measured gains over 8 to 12 weeks. For hay fever and joint pain there is no reliable timeline. Claims of quick relief are not backed by good trials. It may also do nothing at all. That is a real and common outcome with herbs this lightly studied.
• How long to take it: Most trials ran from a few weeks up to six months. Root trials for prostate symptoms often ran 8 to 24 weeks. There is little data on taking nettle for years. If nothing has changed after about eight weeks, longer use is unlikely to help. Long use without a review is not a good idea. Book a check if you keep taking it.