Cat's claw (Uncaria tomentosa, Uncaria guianensis)
Natural Standard Bottom Line Monograph, Copyright © 2013 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.
While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.
Ammonia treated quinic acid, ancajsillo (Peru), ancayacu, aublet, auri huasca, bejuco de agua (Spanish), cat's claw inner bark extract, cell line green Uth-3, C-Med-100®, deixa paraguayo, gambir, garabato, garabato amarillo, garabato blanco, garbato casha, garbato colorado, garbato gavilán, garra gavilán, geissoschizine methyl ether, Gou-Teng, griffe du chat, hawk's claw, jijyuwamyúho, jipotatsa, Krallendorn®, kugkuukjagki, life-giving vine of Peru, misho-mentis, mitraphylline, nature's aspirin, Nauclea aculeate, Nauclea oculeata, Nauclea tomentosa, Ourouparia guianensis, Ourouparia tomentosa, paotati-mösha, paraguaya, Peruvian cat's claw, pole catechu, popokainangra, QA, QAA, quinic acid, radix Uncariae tomentosae (Willd.), rangayo, Rubiaceae (family), samento, tambor hausca, tomcat's claw, torõn, tsachik, tua juncara, Uncaria guianensis, Uncaria tomentosa, uña de gato, uña de gato de altura, uña de gato del bajo, uña de gavilán, uña a huasca, Uncaria guianensis, Uncaria tomentosa, unganangi, unganangui, un huasca, UT extract, UTE, vegicaps.
Note: There are 34 Unicaria species other than Uncaria tomentosa.
Originally found in Peru, the use of cat's claw (Uncaria tomentosa) has been said to date back to the Inca civilization, possibly as far back as 2,000 years. It has been used for birth control, as an anti-inflammatory, as an immunostimulant, for cancer, and as an antiviral. The Peruvian Ashaninka priests considered cat's claw (Uncaria tomentosa) to have great powers and life-giving properties and therefore used it to ward off disease.
Multiple plant species are marketed under the name cat's claw, the most common being Uncaria tomentosa and Uncaria guianensis. Both are used to treat the same indications, although supposedly the former may be a more efficacious immunostimulant.
Cat's claw (Uncaria tomentosa) may be contaminated with other Uncaria species, including Uncaria rhynchophylla (used in Chinese herbal preparations under the name Gou-Teng), which purportedly may lower blood pressure, lower heart rate, or act as a neuroinhibitor. Reports exist of the potentially toxic Texan grown plant, Acacia gregii, being substituted for cat's claw in commercial preparations.
In Germany and Austria, cat's claw is a registered pharmaceutical and can only be dispensed with a prescription. Currently, cat's claw is widely used and is one of the top herbal remedies sold in the United States despite a lack of high quality human evidence.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Early studies have been conducted in Europe assessing the effects of cat's claw in patients with allergic respiratory diseases; a 10-year follow-up revealed that some patients experienced improvements. More research is needed before a conclusion can be made.
Cat's claw may reduce inflammation. Large, high quality human studies are needed comparing the effects of cat's claw alone vs. placebo before a conclusion can be drawn.
Arthritis (osteoarthritis, rheumatoid arthritis)
Cat's claw may reduce inflammation and this has led to research of cat's claw for conditions such as rheumatoid arthritis. Early research suggests that cat's claw may reduce pain from knee osteoarthritis. Further research is needed to confirm these results.
Early research suggests that cat's claw may slow tumor growth. However, this research has not identified specific types of cancer that may benefit; the results are not clear. More studies are needed before a conclusion can be made.
A few early studies suggest that cat's claw may boost the immune system, including in patients with HIV. However, results from different studies have not agreed with each other. Therefore, there is not enough information to make a conclusion for this use.
*Key to grades:A: Strong scientific evidence for this use; B: Good scientific evidence for this use; C: Unclear scientific evidence for this use; D: Fair scientific evidence against this use (it may not work); F: Strong scientific evidence against this use (it likely does not work).
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.
Abscesses, acne, aging, Alzheimer's disease, amnesia, antibacterial, anticonvulsive, antifungal, antihistamine, antimicrobial, antioxidant, antiparasitic, antiviral, appetite stimulant, arrhythmia, asthma, atopic dermatitis, birth control, bowel disease, bursitis, candidal infection, cervical dysplasia, chemical sensitivities, childbirth (recovery), chronic fatigue syndrome, cirrhosis, colds, colitis, Crohn's disease, cysts, dementia, depression, diabetes, diarrhea, digestive problems, diverticulitis, dysentery, edema, endometriosis, fever, fibromyalgia, fistulas, gastritis, gastrointestinal disorders, genetic damage (enhances DNA repair), gingivitis, gonorrhea, gout, heart disease, hemorrhage, hemorrhoids, hepatoprotection, herpes, high blood pressure, high cholesterol, HIV, inflammatory bowel disease (IBD), influenza, kidney cleanser, kidney disease, leaky gut syndrome, leukopenia (chemotherapy-induced), liver disease, long-term debility, lung inflammation, lupus, menstrual irregularity, multidrug resistance of tumor cells, multiple sclerosis (MS), nerve pain, neuroprotection, pain, premenstrual syndrome, prostate problems, radiation side effects, rosacea, sexually transmitted diseases, shingles, sinusitis, skin disorders, sore throats, stimulant, stomach pain, stomach ulcers, stroke, sunscreen, tonic, tumors, ulcers, urinary tract infections, vasorelaxant, weakness, wound healing.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
There is no proven effective dose for cat's claw. Capsules, extracts, tinctures, decoctions, and teas are commercially available. As a capsule, 250-1,000 milligrams has been taken by mouth in divided doses, one to three times daily or 500-600 milligrams once daily. Up to 25 grams of the raw bark has been used in decoctions, although this is based on traditional dosing practices.
Cat's claw is also available in preparations for the skin, but no specific doses have been shown to be safe or effective.
Children (younger than 18 years)
The dosing and safety of cat's claw have not been studied thoroughly in children, and it is recommended that doses are discussed with the child's healthcare provider before starting therapy.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
People with allergies to plants in the Rubiaceae family or any species of Uncaria may be more likely to have allergic reactions to cat's claw. A typical allergic reaction may be itching or severe rash. Allergic inflammation of the kidneys has been reported.
Side Effects and Warnings
Few side effects have been reported from using cat's claw at recommended doses. Most side effects are believed to be rare, and some side effects are theoretical and have not been reported in humans. Examples of possible side effects include stomach discomfort, nausea, diarrhea, slow heartbeats or altered rhythm of heartbeats, kidney disease, acute kidney failure, neuropathy, decreases in estrogen or progesterone levels, and an increased risk of bleeding. Because cat's claw theoretically may increase the risk of bleeding, patients may need to stop taking cat's claw before some surgeries and this needs to be discussed with a qualified healthcare provider. Caution is advised in patients with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.
Some natural medicine experts discourage the use of cat's claw in people with conditions affecting the immune system, such as HIV or AIDS, some types of cancer, multiple sclerosis, tuberculosis, and rheumatologic diseases (rheumatoid arthritis, lupus, etc.). However, there is a lack of specific studies or reports in this area and the risks of cat's claw use in people with these conditions are not clear.
Many tinctures contain high levels of alcohol and should be avoided when driving or operating heavy machinery.
Pregnancy and Breastfeeding
Cat's claw cannot be recommended during pregnancy or breastfeeding. Historically, cat's claw has been used to prevent pregnancy and to induce abortion. Women who are pregnant or wish to become pregnant should not take cat's claw. Many tinctures contain high levels of alcohol and should be avoided during pregnancy.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
In theory, cat's claw may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).
In theory cat's claw may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood and may cause increased effects or potentially serious adverse reactions.
Cat's claw may alter the rhythm of the heart (for example, it may slow heartbeats) or lower blood pressure. Thus, people who take drugs to treat irregular heart rhythms, such as amiodarone (Cordarone®) or digoxin (Lanoxin®) or drugs to lower blood pressure, such as verapamil (Calan®) should use cautiously.
Because cat's claw is believed to affect the immune system, people taking immunosuppressants such as corticosteroids, drugs for rheumatologic diseases (rheumatoid arthritis, lupus, etc.), or drugs to prevent rejection of transplanted organs should consult a healthcare provider and pharmacist before using cat's claw. Examples of such drugs are azathioprine, cyclosporine, and prednisone.
Cat's claw may interact with hormonal agents, cholesterol-lowering agents, diuretics, and agents that affect the kidneys.
Although not well studied in humans, cat's claw may interact with drugs that increase sensitivity to light, analgesics, anesthetics, antibiotics, antihistamines, anti-inflammatory agents, and antiviral agents. Cat's claw may also interact with drugs used to treat cancer.
Many tinctures contain high levels of alcohol and may cause nausea or vomiting when taken with metronidazole (Flagyl®) or disulfiram (Antabuse®).
Interactions with Herbs and Supplements
Very few interactions between cat's claw and herbs or supplements have been reported. In theory, cat's claw may interfere with the way the body processes certain herbs or supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.
It is possible that cat's claw may lower blood pressure. Additive effects may be seen with black cohosh, curcumin, or ginger for example.
Cat's claw may alter the rhythm of heartbeats. As a result, cat's claw should be used carefully if taken with other herbs that affect the heart, such as foxglove/digitalis.
In theory, cat's claw may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.
Cat's claw may decrease estrogen levels and therefore the effects of other agents believed to have estrogen-like properties may be altered.
Cat's claw may decrease the effectiveness of iron supplements and interact with cholesterol-lowering herbs and supplements, diuretics, mushrooms, or herbs that affect the kidneys.
Although not well studied in humans, cat's claw may interact with herbs or supplements that increase sensitivity to light. Other potential interactions are with pain-relievers, anesthetics, antibiotics, antihistamines, anti-inflammatory agents, antioxidants, and antiviral agents. Cat's claw may also interact with herbs used to treat cancer.
This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.
Aguilar JL, Rojas P, Marcelo A, et al. Anti-inflammatory activity of two different extracts of Uncaria tomentosa (Rubiaceae). J Ethnopharmacol 2002;81(2):271-276. View Abstract
Akesson C, Lindgren H, Pero RW, et al. An extract of Uncaria tomentosa inhibiting cell division and NF-kappa B activity without inducing cell death. Int Immunopharmacol 2003;3(13-14):1889-1900. View Abstract
Allen-Hall L, Cano P, Arnason JT, et al. Treatment of THP-1 cells with Uncaria tomentosa extracts differentially regulates the expression if IL-1beta and TNF-alpha. J Ethnopharmacol 1-19-2007;109(2):312-317. View Abstract
Ccahuana-Vasquez RA, Santos SS, Koga-Ito CY, et al. Antimicrobial activity of Uncaria tomentosa against oral human pathogens. Braz Oral Res 2007;21(1):46-50. View Abstract
Cheng AC, Jian CB, Huang YT, et al. Induction of apoptosis by Uncaria tomentosa through reactive oxygen species production, cytochrome c release, and caspases activation in human leukemia cells. Food Chem Toxicol 2007;45(11):2206-2218. View Abstract
Garcia Prado E, Garcia Gimenez MD, De la Puerta V, et al. Antiproliferative effects of mitraphylline, a pentacyclic oxindole alkaloid of Uncaria tomentosa on human glioma and neuroblastoma cell lines. Phytomedicine 2007;14(4):280-284. View Abstract
Hardin SR. Cat's claw: an Amazonian vine decreases inflammation in osteoarthritis. Complement Ther Clin Pract 2007 Feb;13(1):25-8. View Abstract
Kitajima M, Hashimoto K, Yokoya M, et al. Two new nor-triterpene glycosides from peruvian "Una de Gato" (Uncaria tomentosa). J Nat Prod 2003;66(2):320-323. View Abstract
Lee J, Son D, Lee P, et al. Alkaloid fraction of Uncaria rhynchophylla protects against N-methyl-D-aspartate-induced apoptosis in rat hippocampal slices. Neurosci Lett 9-4-2003;348(1):51-55. View Abstract
Lee J, Son D, Lee P, et al. Protective effect of methanol extract of Uncaria rhynchophylla against excitotoxicity induced by N-methyl-D-aspartate in rat hippocampus. J Pharmacol Sci 2003;92(1):70-73. View Abstract
Moreno SR, Silva AL, Dire G, et al. Effect of oral ingestion of an extract of the herb Uncaria tomentosa on the biodistribution of sodium pertechnetate in rats. Braz J Med Biol Res 2007;40(1):77-80. View Abstract
Mur E, Hartig F, Eibl G, et al. 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(4):678-681. View Abstract
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(9):442-448. View Abstract
Setty AR, Sigal LH. Herbal medications commonly used in the practice of rheumatology: mechanisms of action, efficacy, and side effects. Semin Arthritis Rheum 2005;34(6):773-784. View Abstract
Valerio LG Jr, Gonzales GF. Toxicological aspects of the South American herbs cat's claw (Uncaria tomentosa) and Maca (Lepidium meyenii): a critical synopsis. Toxicol Rev 2005;24(1):11-35. View Abstract
Copyright © 2013 Natural Standard (www.naturalstandard.com)
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.
March 22, 2017