Cat’s claw grows in the rain forests of the Andes Mountains in South America, particularly in Peru. The two species of the plant used most commonly are U. tomentosa, which makes up most of the cat’s claw imported to the U.S., and U. guianensis, which is more widely used in Europe. In South America, both species are used interchangeably. The root bark is used as medicine.
Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
100 mg of a freeze-dried preparation daily
Cat’s claw has been used traditionally for osteoarthritis. In a double-blind trial, 100 mg per day of a freeze-dried preparation of cat's claw taken for four weeks was significantly more effective than a placebo at relieving pain and improving the overall condition.2
Refer to label instructions
In a double-blind trial, supplementation with an extract from cat's claw (Uncaria tomentosa) for 24 weeks was significantly more effective than a placebo in reducing the number of painful joints in patients with rheumatoid arthritis. The amount used was 20 mg of extract three times per day. The extract was obtained from a specific strain of cat's claw that contains pentacyclic oxindole alkaloids, compounds that appear to influence the activity of the immune system. The extract was purified to be free of tetracyclic oxindole alkaloids, which may inhibit the beneficial effects of the other alkaloids.3
HIV and AIDS Support
Refer to label instructions
Cat’s claw is another immuno-modulating herb. Standardized extracts of cat’s claw have been tested in small, preliminary trials in people infected with HIV, showing some benefits in preventing CD4 cell counts from dropping and in preventing opportunistic infections.4, 5 Further study is needed to determine whether cat’s claw is truly beneficial for people with HIV infection or AIDS.
Refer to label instructions
Substances found in cat’s claw, called oxyindole alkaloids have been shown to stimulate the immune system.6 However, little is known about whether this effect is sufficient to prevent or treat disease.
Traditional Use (May Not Be Supported by Scientific Studies)
Cat’s claw has been reportedly used by indigenous peoples in the Andes to treat inflammation, rheumatism, gastric ulcers, tumors, dysentery, and as birth control.1 Cat’s claw is popular in South American folk medicine for treating intestinal complaints, gastric ulcers, arthritis, and to promote wound healing.
How It Works
Uña de Gato
How It Works
According to test tube studies, oxyindole alkaloids in cat’s claw stimulate immune function.7 Alkaloids and glycosides in cat’s claw have also demonstrated anti-inflammatory and antioxidant activity.8, 9
Although clinical trials are lacking, cat’s claw has become very popular in North America and is sometimes recommended for people with cancer or HIV infection. A cigarette smoker who took a freeze-dried extract of cat’s claw root bark for one month showed a sharp decrease in one urinary cancer marker.10 This finding, however, does little to support the use of the herb in persons with cancer and points toward the need for actual clinical studies to determine its effectiveness.
Cat’s claw has been used traditionally for osteoarthritis and rheumatoid arthritis. Double-blind trials have confirmed the effectiveness of cat's claw for each of these conditions.1112
How to Use It
In a study of patients with osteoarthritis, 100 mg per day of a freeze-dried preparation was used. Cat’s claw tea is prepared from 1/4 teaspoon (1 gram) of root bark by adding 1 cup (250 ml) of water and boiling for ten to fifteen minutes. Cool, strain and drink one cup three times per day. Alternatively, 1/4–1/2 teaspoon (1–2 ml) of tincture can be taken up to two times per day, or 20–60 mg of a dry standardized extract can be taken once per day.13
Uña de Gato
Interactions with Supplements, Foods, & Other Compounds
At the time of writing, there were no well-known supplement or food interactions with this supplement.
Interactions with Medicines
As of the last update, we found no reported interactions between this supplement and medicines. It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.
Uña de Gato
Although no serious adverse effects have been reported for cat’s claw, there is little known about its safety because most reports have been based on anecdotal evidence. There is one case report in which Parkinson's disease became worse after a man started using cat's claw and improved after cat's claw was discontinued.14 Cat’s claw should be used with caution in people with autoimmune illness, multiple sclerosis, and tuberculosis. Until proven safe, cat’s claw should not be taken by pregnant or breast-feeding women.
1. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 18–9.
2. Piscoya J, Rodriguez Z, Bustamante SA, et al. Efficacy and safety of freeze-dried cat's claw in osteoarthritis of the knee: mechanisms of action of the species Uncaria guianensis. Inflamm Res 2001;50:442–8.
3. Mur E, Hartig F, Eibl G, Schirmer M. Randomized double blind trial of an extract from the pentacyclic alkaloid-chemotype of Uncaria tomentosa for the treatment of rheumatoid arthritis. Rheumatol 2002;29:678–81.
4. Keplinger UM. Influence of Krallendorn extract on retroviral infection. Zürcher AIDS Kongress Zurich, Switzerland, Oct 16–7, 1992 [abstract in German].
5. Keplinger UM. Therapy of HIV-infected individuals in the pathological categories CDC A1 and CDC B2 with a preparation containing IMM-207. IV. Österreichischer AIDS-Kongress, Vienna, Austria, Sept 17–8, 1993, 45 [abstract].
6. Keplinger H. Oxindole alkaloids having properties stimulating the immunologic system and preparation containing same. US Patent no. 5,302,611, April 12, 1994.
7. Keplinger H. Oxyindole alkaloids having properties stimulating the immunologic system and preparation containing same. US Patent no. 5,302,611, April 12, 1994.
8. Aquino R, De Feo V, De Simone F, et al. Plant metabolites, new compounds and anti-inflammatory activity of Uncaria tomentosa.J Nat Prod 1991;54:453–9.
9. Rizzi R, Re F, Bianchi A, et al. Mutagenic and antimutagenic activities of Uncaria tomentosa and its extracts. J Ethnopharmacol 1993;38:63–77.
10. Rizzi R, Re F, Bianchi A, et al. Mutagenic and antimutagenic activities of Uncaria tomentosa and its extracts. J Ethnopharmacol 1993;38:63–77.
11. Piscoya J, Rodriguez Z, Bustamante SA, et al. Efficacy and safety of freeze-dried cat's claw in osteoarthritis of the knee: mechanisms of action of the species Uncaria guianensis. Inflamm Res 2001;50:442–8.
12. Mur E, Hartig F, Eibl G, Schirmer M. Randomized double blind trial of an extract from the pentacyclic alkaloid-chemotype of Uncaria tomentosa for the treatment of rheumatoid arthritis. J Rheumatol 2002;29:678–81.
13. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 18–9.
14. Cosentino C, Torres L. Reversible worsening of Parkinson's disease motor symptoms after oral intake of Uncaria tomentosa (cat's claw). Clin Neuropharmacol 2008;31:293–4.
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
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