Cat’s claw (Uncaria tomentosa) is a tropical vine which can grow up to 98 feet (30 meters) tall. Its name comes from its hooked thorns, which resemble the claws of a cat.

It is found mainly in the Amazon rainforest and in other tropical areas of South and Central America.

The two most common varieties are Uncaria tomentosa and Uncaria guianensis. The former is the type often used in supplements in the United States.

The bark and root have been used for centuries in South America as a traditional medicine for many conditions, such as inflammation, cancer, and infections.

Cat’s claw supplements can be taken as a liquid extract, capsule, powder, or tea.

Potential health benefits

Cat’s claw has soared in popularity as a herbal supplement due to its alleged health benefits — though only the claims below are backed up by sufficient research.

May boost your immune system

Cat’s claw may support your immune system, possibly helping fight infections more effectively.

A small study in 27 men found that consuming 700 mg of cat’s claw extract for 2 months increased their number of white blood cells, which are involved in combating infections. Another small study in four men given cat’s claw extract for six weeks noted the same results.

Cat’s claw seems to work both by boosting your immune response and calming an overactive immune system. Its anti-inflammatory properties could be responsible for its immune benefits.

May relieve symptoms of osteoarthritis

Osteoarthritis is the most common joint condition in the United States, causing painful and stiff joints.

In one study in 45 people with osteoarthritis in the knee, taking 100 mg of cat’s claw extract for 4 weeks resulted in reduced pain during physical activity. No side effects were reported.

However, there was no change in either pain at rest or knee swelling.

In an eight-week study, a supplement of cat’s claw and maca root — a Peruvian medicinal plant — reduced pain and stiffness in people with osteoarthritis. In addition, participants needed pain medication less frequently.

Another trial tested a daily mineral supplement alongside 100 mg of cat’s claw extract in people with osteoporosis. After 1–2 weeks, joint pain and function improved compared to those not taking the supplements.

It should also be noted that it can be difficult to determine the specific actions of cat’s claw in studies that test multiple supplements at once.

Scientists believe that cat’s claw may ease osteoarthritis symptoms due to its anti-inflammatory properties.

May relieve symptoms of rheumatoid arthritis

Rheumatoid arthritis is a long-term autoimmune condition that causes warm, swollen, painful joints. It is increasing in prevalence in the United States, where it affects more than 1.28 million adults.

Some studies suggest that cat’s claw can help relieve its symptoms.

For example, a study in 40 people with rheumatoid arthritis determined that 60 mg of cat’s claw extract per day alongside regular medication resulted in a 29% reduction in the number of painful joints compared to a control group.

As with osteoarthritis, cat’s claw is thought to reduce inflammation in your body, easing rheumatoid arthritis symptoms as a result.