Una de gato, Spanish for “cat’s claw,” is a woody vine native to the Amazon rainforest and tropical regions of Central and South America. The name comes from the small, curved thorns along the vine that resemble a cat’s claws. It has a long history as a traditional remedy among indigenous Amazonian communities and is now widely sold as a dietary supplement, primarily for joint pain and immune support.
The Plant Behind the Name
Two species go by the name una de gato: Uncaria tomentosa and Uncaria guianensis. Both grow wild in the Amazon, but they’re not interchangeable. Most commercial supplements sold in the United States and Europe contain U. tomentosa, which has been more extensively studied and is generally considered the more medicinally relevant of the two.
The vine can climb over 100 feet up rainforest trees. Traditionally, the inner bark and root bark are the parts used medicinally, though recent research has found that even the leaves contain significant concentrations of active compounds.
What Makes It Biologically Active
The compounds that drive most of cat’s claw’s effects belong to a family called oxindole alkaloids. These fall into two categories: pentacyclic and tetracyclic forms. The pentacyclic type is generally associated with immune-stimulating effects, while the tetracyclic type may counteract those benefits, which is why the ratio between the two matters in supplement quality.
Beyond the alkaloids, cat’s claw contains compounds that block an enzyme involved in triggering inflammation. In lab testing, alkaloid-rich extracts inhibited this inflammatory pathway by up to 95%. Some of these same compounds also interfere with an enzyme linked to cognitive decline, which has sparked interest in potential neurological applications, though human evidence in that area is still thin.
Joint Pain and Inflammation
The most studied use of una de gato is for inflammatory joint conditions. In a clinical trial of 50 people with rheumatoid arthritis, a cat’s claw extract outperformed placebo across several measures: fewer painful joints, less morning stiffness, lower pain intensity, and reduced joint swelling. Animal research supports this direction, showing that cat’s claw extract partially reduced joint swelling, pain sensitivity, and markers of inflammation in arthritic rats over a 45-day treatment period.
These results are promising but modest. Cat’s claw appears to help at the margins, reducing symptoms rather than eliminating them. Most people who use it for joint issues take it alongside conventional treatments, not as a replacement.
Immune System Effects
Cat’s claw has a reputation as an immune booster, and there’s some biological basis for that. The pentacyclic alkaloids in the plant appear to influence how immune cells behave, particularly how effectively white blood cells engulf and destroy pathogens. Some early research suggested the plant could enhance DNA repair mechanisms in healthy volunteers, which is relevant to overall cellular health and immune resilience.
This immune-stimulating quality is a double-edged sword. For someone with a healthy immune system looking for general support, it may offer a mild benefit. But for anyone with an autoimmune condition or who takes immunosuppressive medication (such as organ transplant recipients), stimulating the immune system is the opposite of what you want. Cat’s claw is specifically contraindicated for organ transplant recipients for this reason.
Cancer Treatment Research
One area of interest has been whether cat’s claw can reduce the side effects of chemotherapy. A randomized clinical trial tested this directly in 43 colorectal cancer patients undergoing a standard chemotherapy regimen. One group received 300 mg of cat’s claw daily during six chemotherapy cycles, while the other received chemotherapy alone.
The results were neutral. The supplement didn’t reduce rates of low white blood cell counts, low platelet counts, or anemia. It also didn’t change markers of oxidative stress, antioxidant enzyme activity, or DNA damage compared to the control group. On the positive side, no toxic effects were observed, meaning it didn’t make things worse either. Interestingly, animal studies had previously shown that cat’s claw helped neutrophils (a key type of white blood cell) recover faster after chemotherapy, but that finding didn’t translate to the human trial.
How People Take It
Cat’s claw is available as capsules, tablets, liquid extracts, and dried bark for making tea. A typical dose is about 1 gram of root bark taken two to three times daily, or 20 to 30 mg of a concentrated root bark extract. In clinical studies, researchers have used a standardized extract containing 8% to 10% of specific active compounds at doses of 250 to 300 mg daily.
Standardization is worth paying attention to. Because the ratio of pentacyclic to tetracyclic alkaloids affects how the supplement works, products that specify their alkaloid content (and keep tetracyclic alkaloids below 0.5%) are generally considered higher quality. Many cheaper products don’t standardize at all, making it harder to know what you’re actually getting.
Side Effects and Safety Concerns
For most people, cat’s claw is well tolerated. The most common side effects are mild: nausea, digestive discomfort, and diarrhea. Serious reactions are rare.
The more significant concerns involve drug interactions and specific populations. Cat’s claw can interact with blood-thinning medications (anticoagulants), potentially increasing bleeding risk. It’s contraindicated during pregnancy and breastfeeding, and as mentioned, organ transplant recipients should avoid it entirely because of its immune-stimulating properties. If you take medications that are processed by the liver’s enzyme system, the potential for interactions goes up, so it’s worth checking with a pharmacist before adding cat’s claw to your routine.