What is uña de gato?

Uña de gato is a woody climbing vine from the Amazon. Its Spanish name means cat's claw. The name comes from the curved thorns along its stems.

The inner bark and the root bark are the parts used. They are dried and sold as capsules, teas and tinctures. Most products on sale come from Peru.

People take it for joint pain, swelling and so-called immune support. Human evidence is thin and comes from a few small trials. Long use in tradition is not proof that it works, and not proof that it is safe.

How does uña de gato work?

The honest answer is that how it works in people is not settled.

Lab work points to effects on inflammation. In test tube studies, bark extracts lower the activity of NF-kB. NF-kB is a switch inside cells that turns on inflammation genes.

In animal studies, extracts reduced swelling and gut damage. In cell work, some of its alkaloids appear to slow TNF-alpha, a signal that drives inflammation.

Other lab work suggests the plant may help cells repair damaged DNA. All of this comes from cells and rodents. None of it has been confirmed as a real benefit in people.

What forms does uña de gato come in?

Capsules and tablets are the most common form you will see.

These hold either plain dried bark powder or a concentrated extract. The two are not the same strength. The label should say which one you have.

Bark tea is the traditional form. Pieces of inner bark are simmered in water for a long time. In Peru this drink is still widely made.

Tinctures are also sold. These are alcohol extracts, taken in drops.

Two different plants are sold under the same name. Uncaria tomentosa is the usual one. Uncaria guianensis is a close relative, also sold as uña de gato.

Where it comes from:

Uña de gato has a long record of use among Amazonian peoples in Peru. The Asháninka are the group most often named.

Healers boiled the bark into a drink. It was given for joint pain, stomach trouble, fevers and wounds. Some groups also used it after childbirth and in ritual.

Outside interest grew from the 1970s. European researchers studied the alkaloids in the bark. Exports from Peru rose sharply in the 1990s.

This page records that history. It is not a suggestion that you copy those uses at home.

What does uña de gato help with?

• Rheumatoid arthritis, alongside standard medicines: This is the use with the most human data, and the data are still slim. One small trial added a bark extract to standard arthritis drugs. People taking it had fewer painful joints than those on placebo. The effect was modest and the trial was small. It does not show that uña de gato can replace arthritis medicine. Talk to your rheumatologist before adding anything.
• Knee osteoarthritis pain: One short trial used Uncaria guianensis, a close relative, not the usual species. Pain during activity dropped more than with placebo over four weeks. The trial was small and ran for a short time. Rest pain and knee swelling did not clearly improve. This is a promising hint, not a settled finding.
• General joint pain and swelling: Tradition used the bark drink for aching joints and back pain. Lab and animal work shows anti-inflammatory activity. There are no good trials for everyday joint pain outside arthritis. If your pain is new, severe or one-sided, get it checked first.
• Immune support: Marketing often calls uña de gato an immune booster. Small studies have looked at white blood cell counts and vaccine response. Results were mixed and the studies were very small. There is no proof that it prevents colds or other infections. If you have an autoimmune disease or take immune-damping drugs, this is a reason for caution, not a selling point.
• Stomach and bowel complaints (traditional use): Healers used the bark for gastritis, ulcers and loose bowels. Animal work shows some protection of the gut lining. Human trials for gut problems are essentially absent. Ongoing stomach pain, bleeding or weight loss needs a doctor, not a herb.
• Wound healing and fevers (traditional use): The bark was used in washes for wounds and as a drink for fevers. These uses are recorded by ethnobotanists. We found no human trials testing either use. Treat these as history, not as tested options.

What are the side effects of uña de gato?

• Nausea
• Diarrhoea or loose stools
• Stomach pain
• Headache
• Dizziness
• A drop in blood pressure
• Skin rash or itching
• Rare reports of kidney injury
• Rare reports of liver injury

Good to know:

Most reported effects are mild and settle when people stop.

Stomach upset and headache are the usual complaints. Dizziness can follow a drop in blood pressure.

Serious harm is rare but has been reported. Case reports describe sudden kidney injury and liver problems. Stop and seek care if you feel genuinely unwell.

How much uña de gato should you take?

• Recommended daily: Label amounts vary widely, because products are not alike. Standardised extract capsules often list 250 mg to 350 mg, once or twice a day. Plain dried bark capsules often list about 1 to 2 grams a day. The arthritis trials used much smaller amounts of concentrated extract, around 60 mg to 100 mg a day. These are label and study figures only. They are not an amount chosen for you, and they are not advice.
• Best time of day: Time of day does not appear to matter. No study has compared morning with evening use. Some people find it easier on the stomach when split across the day.
• With or without food: Food is not required, but it may help. Nausea and loose stools are the most common complaints. Taking it with a meal can ease both.
• Time to effect: In the arthritis trials, differences showed up slowly, over about four to eight weeks. It may also do nothing at all for you. If nothing has changed after about eight weeks, there is little reason to keep going.
• How long to take it: No safe long-term period has been set. The longest published trial ran for about a year in people already under medical care. Most other studies lasted four to eight weeks. Safety beyond a year is not well studied. If you use it at all, short, reviewed periods make more sense than open-ended use.