Cat's Claw

Uncaria tomentosa · Una de Gato · Uncaria guianensis

Snapshot

Indications	Contraindications
Osteoarthritis symptoms^{1, 2} Rheumatoid arthritis symptoms³ Quality of life in advanced cancer⁴ Immune function^{5, 6} DNA repair markers⁶	Pregnancy⁷ Autoimmune disease⁷ Upcoming surgery⁷

Cat's claw is a woody Amazonian vine, and Uncaria tomentosa is the species in most U.S. commercial preparations⁷. Extracts are taken for anti-inflammatory and immune-modulating effects, which in animal studies track with lower interleukin-6 and nuclear factor kappa-B⁸. Adults with joint pain from osteoarthritis or rheumatoid arthritis are typical users, and it is also taken for fatigue in advanced cancer and for immune function.

Human research is limited to about nine small trials, mostly in osteoarthritis and rheumatoid arthritis. The National Center for Complementary and Integrative Health (NCCIH) finds no conclusive human evidence for any health purpose⁷. A small rheumatoid arthritis trial found modest benefit on painful joints, while a meta-analysis found no difference from control in osteoarthritis. In a 2020 laboratory study, cat's claw extract was active against the non-growing stationary phase of the Lyme disease bacterium, and no human trial has tested it. Products are mostly capsules of bark or standardized extract; see Form comparison.

NCCIH notes cat's claw might increase immune activity and slow clotting, and directs people with autoimmune disease or upcoming surgery to consult their health care provider⁷. A systematic review found cat's claw raised antiretroviral levels, and its authors advised monitoring for adverse effects⁹.

Last updated October 15, 2026. Read how we make monographs.

In the full monograph

40 sources, 30 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources