Cat’s claw is a vine that grows in the rainforest in South and Central America. The two most common species are Uncaria tomentosa and Uncaria guianensis.
Cat’s claw root and bark contain chemicals that might stimulate the immune system, kill cancer cells, and fight viruses.
People use cat’s claw for cancer, osteoarthritis, rheumatoid arthritis (RA), viral infections, and other conditions, but there is no good scientific evidence to support any of these uses. There is also no good evidence to support using cat’s claw for COVID-19.
There are claims that cat’s claw contains substances that stimulate the immune system, neutralise cancer cells and combat viruses. There hasn’t been much research undertaken to assess these claims, but one study published in Alimentary Pharmacology and Therapeutics found that cat’s claw protects against oxidative stress, supporting the notion that it is an effective anti-inflammatory agent.
Research from the Journal of Rheumatology also suggests that cat’s claw extract (uncaria tomentosa) when taken with other medications (sulfasalazine or hydroxchloroquine) for 24 weeks can help reduce the symptoms of painful and swollen joints in those with rheumatoid arthritis.
There isn’t enough evidence to support other claims such as protecting against genital warts, stomach ulcers, haemorrhoids, shingles, chronic fatigue syndrome, asthma, HIV or cancer.