Health Benefits of Cat's Claw

What research says about use for arthritis and other concerns

Red and yellow cat's claw flower in bloom

 NancyAyumi / Getty Images

Cat's claw (Uncaria tomentosa) is a woody vine native to the Amazon and Central American rainforests. Cat’s claw bark and root, often made into a tea, have been used for centuries by South Americans as a remedy for a wide range of ailments, including stomach ulcers and fevers. Most of these uses are unsupported by scientific evidence or only have early evidence supporting their use.

That said, several identified properties of cat's claw make it attractive to medical researchers. It has been shown to have immune-modulating, antioxidant, and anti-inflammatory effects and research is looking into its potential use for several concerns, including some types of arthritis, Lyme disease, and cancer.

Cat's claw, also known by its Spanish name Uña de Gato, is sometimes referred to as the "life-giving vine of Peru." Its name is derived from the hook-like thorns that resemble the claws of a cat. It should not be confused with cat's claw acacia, which contains a potentially poisonous cyanide compound.

Arthritis

Cat's claw contains a unique compound known as pentacyclic oxindolic alkaloid (POA) that is believed to have anti-inflammatory effects, which makes it attractive as a possible treatment for arthritis. POA appears to block the production of inflammatory substances such as tumor necrosis factor-alpha (TNF-a).

TNF-a helps regulate the immune response and, among other things, is responsible for inducing fever, inflammation, and apoptosis (programmed cell death) in old or damaged cells.

Some small, preliminary studies from 2001 and 2002 suggest that cat's claw may reduce pain in people with rheumatoid arthritis (RA), an autoimmune disease, and osteoarthritis ("wear-and-tear arthritis").

However, while a 2010 review states that three studies support cat's claw for osteoarthritis (either alone or in combination with other treatments), researchers didn't find credible evidence that it was effective for RA. They also stated that not enough high-quality follow-up studies have been done to say for certain whether it's safe and effective for either condition.

Lyme Disease

A special type of cat's claw, known as samento, is believed to aid in the treatment of Lyme disease. Proponents claim that samento is able to "boost" the immune system more effectively than regular cat's claw because it is devoid of a compound called tetracyclic oxindole alkaloid (TOA), which is believed to inhibit POA.

Early evidence for samanto came from test tube studies in which the plant was better able to neutralize the bacteria Borrelia burgdorferi, which leads to Lyme disease, than the antibiotic doxycycline. Later research strongly recommended clinical studies to see whether in vitro results could translate into successful treatments.

Until those studies come along, though, the veracity of the health claims will remain largely unsupported.

Cancer

Some early test tube studies have suggested that the POA found in cat's claw may have anti-tumor properties. It is believed that POA is toxic in specific cancers cells and may have less impact on the healthy cells that are typically damaged by chemotherapy.

A 2010 study from the University of Seville reported that POA derived from the bark of cat's claw was able to kill and prevent the spread of breast cancer and Ewing's sarcoma cells in test tube studies. While the cytotoxic (cell-killing) effect was similar to that of the drug Cytoxan (cyclophosphamide), the dose needed to achieve this effect in humans would likely be unreasonable. Still, the finding hints at a promising new avenue for cancer drug development.

A 2016 study suggested that different strains of cat's claw can kill different types of cancer cells, including those from bladder cancer and glioblastoma, a type of brain cancer. This research found that cat's claw doesn't harm healthy cells.

Dosage and Preparation

Cat's claw supplements are generally sold in capsule and tincture formulations. The herb is also available in tea bags or purchased as loose "wild-crafted" powders and bark chips.

There is no official guidance as to the appropriate use of cat's claw. Dosing recommendations vary by manufacturer and are guided more by current practices than by hard evidence.

Capsule formulations are generally considered safe at doses of up to 350 milligrams (mg) daily. The dosing of cat's claw tinctures can vary by the strength of the formulation, but 1 to 4 milliliters (ml) daily is the most commonly recommended dose. As a rule of thumb, never take more than is recommended on the product label.

At this time, there is little scientific data on how long cat’s claw can be used safely. However, published clinical trials lasting from four weeks to a year have reported relatively few side effects.

How to Make Cat's Claw Tea

The indigenous people of Peru boil traditionally boil 20 to 30 grams (g) of the inner bark or root in a liter of water for 30 to 60 minutes.

For home use, you can steep one tablespoon (2 g) of dried cat's claw powder in one cup of hot water for five to 10 minutes.

The flavor of the tea, unsurprisingly, is bitter and woody. Some people like to mix it with rooibos tea, honey, and lemon to make it more palatable.

Possible Side Effects

Cat's claw may cause side effects in some people, including:

  • Nausea
  • Headache
  • Dizziness
  • Diarrhea
  • Vomiting
  • Low blood pressure

Most side effects resolve on their own once the treatment is stopped.

Cat's claw can also slow blood clotting, leading to easy bruising and bleeding (particularly in people on anticoagulants). Because of this, you should stop taking cat's claw at least two weeks before surgery to avoid excessive bleeding.

Drug Interactions

Cat's claw is known to interact with many pharmaceutical drugs, including:

Always make sure your doctor knows about all drugs and supplements you're taking so they can watch for dangerous interactions. Your pharmacist is also a valuable resource to consult with.

Contraindications

Because cat’s claw is believed to stimulate the immune system, the herb should not be used by:

Cat's claws may trigger a relapse of symptoms or, in the case of organ transplants, lead to organ rejection.

Due to the lack of safety research, children, pregnant women, and nursing mothers should not use cat’s claw.

Talk to your doctor before using cat’s claw to make sure it's safe for you.

What to Look For

Cat's claw, like other herbal supplements, is not subject to rigorous testing and research in the United States. As such, quality can vary from one brand to the next, particularly those that have been imported from another country.

To ensure quality and safety, only purchase supplements from manufacturers with an established brand presence. While vitamin supplements are often voluntarily submitted for testing by an independent certifying body like the U.S. Pharmacopeia or ConsumerLab, herbal supplements rarely are. And none of these products are regulated by the U.S. Food and Drug Administration (FDA). This can leave you blind as to what is inside a supplement and what is not.

As an added layer of safety, opt for brands that have been certified organic under the regulations of the U.S. Department of Agriculture (USDA). This will reduce your risk of exposure to pesticides and other chemical toxins.

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