Cat’s Claw

Background

• Cat’s claw is a woody vine that grows wild in the Amazon rainforest and other tropical areas of Central and South America.
• The two most common species are U. tomentosa and U. guianensis. Most commercial preparations of cat’s claw in the United States contain U. tomentosa.
• Indigenous people of the Amazon rainforest have used cat’s claw for centuries to ward off disease.
• Today, cat’s claw is promoted for osteoarthritis, rheumatoid arthritis, cancer, viral infections, and other conditions.

How Much Do We Know?

• There have been very few high-quality clinical trials (studies done in people) of cat’s claw.

What Have We Learned?

• There’s no conclusive scientific evidence based on studies in people that supports using cat’s claw for any health purpose, including COVID-19. Some research has been done in people on the effect of cat’s claw on various conditions, but many of the studies did not use rigorous methods and did not include enough study participants to allow definite conclusions to be reached.

What Do We Know About Safety?

• Cat’s claw appears to be safe when used orally for short periods of time, as much as 6 months. However, there is insufficient reliable information about its safety when applied to the skin. Cat’s claw might make the immune system more active, which could increase symptoms of autoimmune diseases. If you have an autoimmune disease, consult your health care provider before using cat’s claw.
• Cat’s claw may slow blood clotting, and this might increase the risk of bleeding during surgery. Talk to your health care provider if you take cat’s claw and you are scheduled to have surgery.
• There are theoretical reasons to suspect that cat’s claw might interact with anticoagulant, antiplatelet, and blood pressure drugs, and other supplements as well. If you take any type of medicine, talk with your health care provider before using cat’s claw or other herbal products; some herbs and medicines interact in harmful ways.
• Some studies of the use of cat’s claw during pregnancy suggest it is unsafe. Little is known about whether it’s safe to use cat’s claw while breastfeeding.

Keep in Mind

• Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.
• Federal Regulation of Herbal Products
  • Depending on what’s in them, how they’re intended to be used, and how they’re administered (orally or topically), herbal products are regulated in a variety of ways. Many herbal products intended for oral use are marketed as dietary supplements. The rules for making and distributing dietary supplements are less strict than those for drugs.
  • Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold to the public. When public health concerns arise about the safety of a dietary supplement or an ingredient including an herb, the FDA can take action to protect the public. Manufacturers and distributors of supplements are responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all regulatory requirements. 

For More Information

• Using Dietary Supplements Wisely
• Know the Science: How Medications and Supplements Can Interact
• Know the Science: How To Make Sense of a Scientific Journal Article

Key References