Cat’s Claw: Uses, Research, Side Effects and Who Should Avoid It

Cat’s claw is a woody vine from the Amazon rainforest and other tropical parts of Central and South America, sold as a bark supplement and marketed for immune support and comfort. The National Center for Complementary and Integrative Health (NCCIH) says there is no conclusive evidence from studies in people that it helps with any health purpose. It can also interact with medicines, may affect the immune system and bleeding, and may be unsafe in pregnancy. Here is what the plant is, what the few human trials tested, the safety facts and how to read a label that lists it.

Peptide Labs does not sell a cat’s claw supplement. One multi-herb cleanse we carry lists it in a blend, described below with label facts only. This article is general information, not medical advice.

What is cat's claw?

The name comes from the hooked thorns on the vine. In Spanish it is called una de gato. NCCIH lists two main species: Uncaria tomentosa, the one most common in US products, and Uncaria guianensis. Indigenous Amazonian peoples have used the bark traditionally, and today it is sold as capsules, tablets, tinctures and tea. Do not confuse it with garden plants that share the common name, such as the cat’s claw creeper or cat’s claw acacia, which are unrelated.

The bark contains compounds called oxindole alkaloids. Researchers describe two chemical types, pentacyclic (POA) and tetracyclic (TOA), and extracts vary widely depending on the plant, the part used and how it was processed. A 2025 review of laboratory studies found that results changed with the extraction method and called for standardization. That variation is one reason studies are hard to compare and one product may not behave like another.

Cat's claw benefits: what the research shows

Cat’s claw is promoted for osteoarthritis, rheumatoid arthritis, cancer, viral infections and immune health. NCCIH notes that few high-quality trials exist and that existing studies often lacked rigorous methods and enough participants. Memorial Sloan Kettering’s herb database adds that cat’s claw has not been shown to be effective for cancer or AIDS.

These human trials enrolled a few dozen people each, lasted one to six months and used specific extracts that may not match what is on store shelves. In the rheumatoid arthritis study, everyone was also taking prescribed medicines, so the herb was an add-on, not a replacement. Animal and cell results show possible mechanisms only; they do not show that a supplement helps people.

Cat's claw and Lyme disease

Some products and websites promote cat’s claw for Lyme disease. No controlled human evidence reviewed for this article supports that use, and NCCIH’s conclusion covers every health purpose. Lyme disease needs diagnosis and care from a clinician. If you have a tick bite followed by a rash, fever or aches, see a clinician rather than starting an herbal product.

Cat's claw side effects

In studies, cat’s claw appeared safe when taken by mouth for up to six months. Memorial Sloan Kettering lists nausea, diarrhea and stomach discomfort as the common side effects. Case reports describe more serious problems, including kidney failure in a person with lupus and worsened movement symptoms in a person with Parkinson’s disease. Case reports cannot prove cause, but they are a reason for caution in people with chronic conditions.

Drug interactions and who should avoid cat's claw

• Pregnancy: NCCIH says some studies suggest it is unsafe during pregnancy, and there is little information on breastfeeding. Avoid it unless your obstetric provider advises otherwise.
• Autoimmune conditions: NCCIH notes it may activate the immune system, which could worsen conditions such as lupus, rheumatoid arthritis or multiple sclerosis.
• Immune-suppressing medicines: because of that possible immune effect, people taking medicines that dampen the immune system, such as after an organ transplant, should not add it without their prescriber’s approval.
• Blood thinners and surgery: it may slow blood clotting. Memorial Sloan Kettering advises against combining it with warfarin, and NCCIH flags anticoagulants and antiplatelet drugs. Tell your surgical team if you use it.
• Blood pressure medicines: NCCIH lists possible interactions.
• HIV medicines and other drugs: a published case report linked cat’s claw to raised blood levels of atazanavir, ritonavir and saquinavir, and lab studies show it can inhibit CYP3A4, the liver enzyme that handles many prescriptions.

If you take any prescription, ask a pharmacist to check before trying cat’s claw. Herbs with similar interaction concerns, such as St. John’s wort, show how a supplement can change the way medicines work.

Cat's claw in combination products

Cat’s claw often appears in multi-herb blends marketed for immunity or cleansing, usually without a listed amount. Our catalog has one example: The Cleaner Detox Women’s 7 Day Formula lists cat’s claw among about two dozen botanicals in a proprietary blend led by soluble fiber and senna leaf, so the amount of cat’s claw is not disclosed. Its label warns not to use it with diarrhea, loose stools or abdominal pain, not to use it for more than 7 days in a row unless a doctor directs, and to consult a physician if pregnant, nursing or taking medication; it is not for children under 12 and contains soy. Senna is a stimulant laxative, so that product is a cleanse, not a cat’s claw supplement. Our guide to colon cleanse supplements explains what those products do.

If you compare herbs marketed for immune support, our guides to echinacea and elderberry summarize their evidence the same way, and our guide to third-party tested supplements explains what quality seals check.

How to read a cat's claw label

1. Check the species (Uncaria tomentosa or Uncaria guianensis) and the plant part, usually inner bark or root.
2. See whether the amount is listed or hidden in a proprietary blend.
3. Note any extract description such as “TOA-free” or “POA”, and remember that these terms are not standardized across brands.
4. List every other herb in the product and check each one for interactions.
5. Read “immune support” as a marketing statement the FDA has not evaluated.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

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