Cat’s claw is a wood-like vine that has been used for hundreds of years by healers in Central and South America.
Cat’s claw extract supplements are derived from the bark of the Uncaria tomentosa plant. The herb is a source of oxindole alkaloids and polyphenols.
This plant extract is most commonly used for boosting immunity, supporting joint health and as an antioxidant. It is also purported to have benefits for brain health and DNA repair.
Research shows that it works by relaxing smooth muscle tissue, opening blood vessels (vasodilation), and helping to rid the body of excess fluid accumulations by stimulating dieresis (increased urine production). [1, 2]
This article will discuss the active phytochemicals found in cat’s claw supplements, common uses, health benefits, dosage guidelines, how to take this product as well as safety and side effect information.



- May improve joint pain and swelling
- Protects against free radical agents
- Support lymphocyte (white blood cell) activity
What is Cat’s Claw?
The cat’s claw herb comes from the Uncaria tomentosa or Uncaria guianensis plants. These two varieties of the plant are most studied for their medicinal effects.
Uncaria tomentosa is used most frequently in the United States, while Uncaria guianensis is more common in Europe.
Most commercial products are formulated using Uncaria tomentosa, and it has been studied more extensively.
The bark and root of this plant have been used in traditional medicines for inflammation, fever, stomach ulcers and severe intestinal infection (dysentery). Traditionally cat’s claw has also been used as a contraceptive.
Commonly called Una de Gato, this herb has been used in various medicine systems in Central and South America, especially in tropical jungle regions of the Amazon Rainforest.
Peruvian healers used this healing plant for a diverse range of disorders including cancer, stomach disorders, and to enhance wound healing. [3]
Uncaria tomentosa is classified as a liana, or a long vine with grounded roots that climbs trees and other vertical supports to reach sunlight in the canopy.
Cat’s claw is so-named because it develops small yellow flowers and hooked thorns that look like the claw of a cat.
These sharp-pointed thorns are used to latch onto vertical supports and climb. The vines of the Uncaria tomentosa can grow up to one hundred feet in length.
Cat’s claw root and bark contains a variety of alkaloid chemicals. Alkaloids are organic compounds that contain nitrogen and oxygen and can induce physiological effects in humans.
Some common alkaloids include quinine, caffeine, morphine, nicotine, and cocaine. The primary alkaloid in cat’s claw is called rhynchophylline.
Some evidence suggests that this alkaloid might help to improve cardiovascular conditions by opening blood vessels (vasodilation), decreasing heart rate, and possibly decreasing levels of serum cholesterol.
It is thought that rhynchophylline might also slow down activities of the sympathetic nervous system. [4]
Additional effects that have been observed in in vitro, animal, and preliminary human research include the following mechanisms of action:
- Antibacterial
- Antiviral
- Antiparasitic
- Anti-inflammatory
- Antimutagenic (Prevent Mutations)
- Antitumor
- Cytostatic (Inhibit Cell Growth)
- Detoxifying
- Hypotensive (Blood Pressure Lowering)
- Immunostimulant [1, 2, 3]
Research in humans is limited and more studies are needed to determine the efficacy of this herb for various conditions.
How Does Cat’s Claw Work?
Cat’s claw extract supplements exhibit several different properties that may support health and well-being.
This herb is a potent antioxidant that can help to reduce cell and tissue damage from radical agents like free radicals, food and water toxins, pollutants and more.
By inhibiting oxidative damage from free radicals, this compound might help to reduce the risk of developing health conditions associated with chronic exposure to pro-oxidant compounds.
The anti-inflammatory effects of cat’s claw herb have been observed in clinical research to improve osteoporosis – a condition marked by brittle, fragile bones. [4]
This herb might help patients with osteoporosis by inhibiting the production of two proinflammatory cytokines called tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E2.
Researchers believe cat’s claw might also benefit rheumatoid arthritis (RA). [4]
Certain pentacyclic alkaloids in cat’s claw are purported to be immunomodulatory, which means they may help to regulate the activities of the immune system.
These alkaloids support immune function by upregulating lymphocyte (white blood cell) activity and enhancing a process called phagocytosis wherein immune cells called phagocytes ingest bacteria. [4]
In animal research, cat’s claw affects several different types of white blood cells including B lymphocytes, T lymphocytes, natural killer (NK) cells, and granulocytes.
This herb does not appear to alter the natural proportions of these white blood cells types. [4]
Because it does not appear to increase the biological precursors of these cell types, researchers believe that it must extend the life of the lymphocytes already present. [4]
Animal studies also suggest that cat’s claw may improve recovery from increased leukocyte counts (leukopenia) that results from treatment with a common chemotherapy agent called doxorubicin. [4]
Quinovic acid alkaloids as well as alkaloid pteropods and isopteropodine, seem to possess immunostimulant, antiviral, and antioxidant properties which are of interest for combating cancer and various viral infections. [4]
According to the Natural Medicines Comprehensive Database (NMCD) some studies suggest that this compound can induce normal genetically-mandated death in cancer cells in a process called apoptosis.
Other evidence suggests that cat’s claw has antimutagenic activities that prevent healthy cells from mutating into cancerous cells. [4]
In one animal study, this plant extract was found to inhibit the rapid replication (proliferation) of both lymphoma and leukemia cells. [4]
Other animal research suggests that the alkaloids in this herb might be helpful for improving memory loss due to cholinergic dysfunction. This effect may occur due to increased production of a neurotransmitter called acetylcholine.
In one mice study, another plant chemical in cat’s claw called uncarine E was observed to alter activity in the glutamatergic system which may affect cognition and/or memory. [4]
Most of the mechanisms of action of cat’s claw are not well understood or have not been validated in human trials yet. Research continues to better understand how this supplement works in humans.
Common Uses of Cat’s Claw
The NMCD reports that people use cat’s claw in alternative medicine practices for the following conditions:
- Alzheimer’s disease
- Chronic fatigue syndrome (CFS)
- Herpes zoster and herpes simplex
- Human immunodeficiency virus (HIV)
- Human papillomavirus (HPV)
- Leaky bowel syndrome [4]
The NMCD reports that cat’s claw is also used for various gastrointestinal disorders, including peptic ulcers, diverticulitis, colitis, dysentery, and gastritis.
Some people also use it for hemorrhoids, parasites, wound healing, asthma, and hay fever (allergic rhinitis). This supplement has also been used for bone and joint pain, urinary tract cancer, and detoxifying the kidneys. [4]
The University of Maryland Medical Center states other uses for cat’s claw supplements including balancing intestinal flora, irritable bowel syndrome (IBS), immune system deficiencies, and improving DNA repair. [1]
If you are interested in taking a cat’s claw supplement to address a specific health concern, it is best to speak with your doctor before beginning use. Your doctor will be able to determine if this supplement is right for your needs.
Cat’s Claw Health Benefits
The NMCD has rated cat’s claw as Possibly Effective for osteoarthritis and rheumatoid arthritis. [4]
The UMM states that this supplement is also being investigated for systemic lupus erythematosus (SLE), endometriosis, bladder cancer, kidney problems, Crohn’s disease and multiple sclerosis (MS). [1]
Promising results have been seen preliminary clinical research using this herb for cancer, HPV, and immune cell production. These studies are limited, and more research is needed to determine the therapeutic efficacy of this supplement for these and other conditions.
Cat’s claw extract is regulated as a dietary supplement and the FDA has not approved it as a drug to prevent or treat any medical conditions.
Osteoarthritis
Cat’s claw has been used traditionally for osteoarthritis for many years. Recently, some clinical studies have been conducted to evaluate this use.
The UMM notes that one clinical study showed cat’s claw reduced knee pain due to osteoarthritis without causing any adverse effects. [1]
According to the NMCD, some people use a combination supplement called Reparagen for osteoporosis symptoms. This supplement contains 300 mg cat’s claw and 1500 mg maca per serving. [4]
In a study, twice daily 1800 mg Reparagen doses for 8 weeks was found to decrease stiffness and pain, improve locomotion and performance, and decrease the need for rescue medicines in people with osteoarthritis. [4]
In another clinical study, patients were administered either a freeze-dried preparation of Uncaria guianensis or a placebo. Pain, patient assessment scores, and side effects were measured at 1, 2, and 4 weeks.
It was observed that pain associated with activity was decreased in the Uncaria guianensis group, although knee pain at rest was not significantly affected by the treatment. [4]
More research is still needed to fully understand how cat’s claw can affect osteoarthritis. If you are interested in taking this supplement it is recommended that you speak with your doctor or osteopath to determine if it is right for your needs.
Rheumatoid Arthritis
Rheumatoid arthritis (RA) is an autoimmune disorder in which the immune system attacks the joints. This causes pain and swelling (inflammation), due to thickening of synovium that lines points of contact on the insides of joints.
Normally, synovium acts to produce a fluid that lubricates and facilitates smooth movement in joints. [4]
In clinical research, it has been observed that cat’s claw can reduce the swelling and pain that result from RA.
In a small study, patients who were already taking the prescription medications hydroxychloroquine or sulfasalazine were given either a placebo or a Uncaria tomentosa supplement for 24 weeks.
At the end of that trial period, the placebo patients were also given Uncaria tomentosa and both groups continued treatment for a further 28 weeks.
It was observed that the patients who received the herbal treatment in the first trial period had a reduction in the number of painful joints compared to the placebo patients. [4]
The patients who started on the placebo and were then given the active treatment in the second period were observed to have a reduction in their number of painful and swollen joints in the second period compared to their time on placebo. [4]
Even though cat’s claw does reduce pain and swelling in RA patients, it does not inhibit the progression of existing joint damage. Some doctors use this plant extract as an adjunct therapy along with pharmaceuticals that are able to inhibit joint damage progression. [4]
The NMCD states that cat’s claw seems most effective for RA when used in conjunction with sulfasalazine or hydroxychloroquine, as in the study described above. [4]
If you are interested in learning more about the use of this supplement for RA, consult with your doctor or immunologist to ensure that it is right for your needs.
Anti-Cancer Research
According to NMCD, preliminary clinical research shows that using a specific cat’s claw extract, standardized to contain 5% mitraphylline can improve life quality in terminal patients with advanced cancer.
Taking three daily 100 mg doses improved social functioning skills, fatigue and overall quality of life. [4]
A trial in women who were undergoing chemotherapy for breast cancer found that the normal reductions in leukocytes, lymphocytes, and neutrophils (types of white blood cells) seen with chemotherapy was reduced when 300 mg of Uncaria tomentosa extract was given along with the chemotherapy treatment. [6]
The researchers suggested that this may be due to increasing the length of survival of immune cells and reducing apoptosis (programmed cell death). [6]
More research is needed to determine the therapeutic efficacy of cat’s claw for cancer, and its use as an adjunct treatment.
If you are interested in taking this supplement it is recommended that you talk with your doctor or oncologist about the safety of using cat’s claw for cancer or as an adjunct therapy with conventional cancer medications.
Cat’s Claw Supplements
The UMM states that the root and bark of cat’s claw are sometimes crushed and used to make teas and tinctures.
Liquid extracts and capsules are also available; often standardized to contain 15% phenols and 3% alkaloids.
A large percentage of the cat’s claw sold in the US is grown in Peru. [1]
The NMCD states that there are over 500 different dietary supplements that contain cat’s claw. When possible you should try to find supplements that have been organically sourced, are free of contaminants, and sold by reputable manufacturers who produce their supplements in cGMP compliant facilities. [4]
Most cat’s claw supplements contain 1000 mg extract per dosage with a recommended serving size of 1-3 capsules per day.
Cat’s Claw Dosage
The optimal dose of cat’s claw extract will depend on individual factors including age, weight, sex, the reason for taking a supplement, state of health, and other factors.
The following dosages have been used in research studies:
- Cancer: 100 mg three times per day for at least 8 weeks
- Osteoarthritis: 100 mg per day
- Osteoarthritis: 300 mg, twice per day
- Rheumatoid Arthritis: 20 mg, three times per day [4]
Discuss the best dosage of cat’s claw extract for your needs with a doctor who is familiar with your health history and any other supplements or drugs you may be taking.
Safety and Side Effects
NMCD rates cat’s claw as Possibly Safe when used orally for short-term periods by adults. It is rated as Possibly Unsafe for use during pregnancy. [4]
The UMM advises that children under 12 years of age should not take this supplement, unless recommended and monitored by a doctor.
According to the National Center for Complementary and Integrative Health (NCCIH), few people experience adverse side effects when taking cat’s claw orally in small amounts. [5]
The NCCIH recommends that pregnant women and those trying to become pregnant should not take this supplement. This is because cat’s claw has been used traditionally to prevent and abort pregnancies. [4]
According to NMCD, this plant extract is generally well tolerated and there have been no serious side effects reported in research studies. [4]
The NMCD states that it may cause diarrhea when taken in high doses. Other possible minor side effects include headache, nausea, vomiting, and/or dizziness. [4]
The UMM states that the following groups should not use cat’s claw supplements without medical advice and supervision:
- People receiving skin grafts or organ transplants
- People with autoimmune diseases like RA, lupus and psoriasis
- People with hypotension (low blood pressure)
- People with leukemia
- People with liver and/or kidney disease [1]
If you have any chronic health condition it is best to talk with a doctor before beginning to use a cat’s claw herbal supplement.
Drug and Supplement Interactions
According to the NMCD, people using any of the following types of medications should avoid taking this supplement unless supervised by their doctor:
- Blood pressure medications
- Diuretics used to eliminate excess fluids
- Drugs that thin the blood, including Plavix (clopidogrel), warfarin and aspirin
- Medications that suppress immune system activities, like cyclosporine [4]
The NMCD states that cat’s claw should not be used with medications that are metabolized in the liver. If you take any prescription medications, it is best to discuss this supplement with your doctor before purchasing it to determine whether it is appropriate for you.
- University of Maryland Medical Center. Cat's Claw. Accessed Feb.8, 2017
- Cat's Claw. Accessed Feb.8, 2017
- Cats Claw (Uncaria Tomentosa). Accessed Feb. 8, 2017
- Natural Medicines Comprehensive Database. Cat's Claw Monograph. Accessed Feb. 8, 2017
- Cat's Claw. Accessed Feb. 8, 2017
- Kamal, Examine Staff. Unicaria tomentosa. Examine.com.
Article last updated on: June 26th, 2018 by Nootriment