Stinging nettle

Stinging nettle is applied to the skin to give a counterirritant effect which can override musculoskeletal pain. There’s little evidence available on the use of nettle leaves for osteoarthritis: one study suggested a positive effect in the short-term treatment of osteoarthritis of the thumb but another found no beneficial effect in the short-term treatment of osteoarthritis of the knee.

• Family: Herbal medicine of the nettle (Urticaceae) family
• Scientific name: Urtica dioica
• Other names: Common perennial nettle

Stinging nettle is a plant native to Europe, Asia, and North America. You can buy capsules from high-street shops, although the trials below applied nettle leaves to participants’ skin.

Nettle leaves are covered in tiny hairs which have a high silicon content, meaning they’re extremely brittle. When the leaf touches your skin, the round tips of the hairs break off. The sharp point of the hair then enters your skin and several chemicals, including histamine and serotonin, are produced. These chemicals can help to reduce pain by stimulating pain neurons, so the skin irritation overrides musculoskeletal pain.

You can apply stinging nettle to the skin around the painful area. Common side-effects include itching and a tingling sensation. Because it can be applied to the skin, it’s unlikely that it’ll affect other medications.

We don’t have much information about dosage, but nettle leaves were applied to the painful area for two 30-second periods for one week in one study.

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.