Medically reviewed by Suzanne Fisher, RD
Cat's claw, also known as Uncaria tomentosa, is a plant native to the Amazon. It is most commonly studied for its anti-inflammatory and antitumor effects.
This article describes the potential benefits of supplementation with cat's claw and important safety considerations.
Cat's Claw Supplement Facts
Active Ingredient(s): Quinovic acid glycoside, as well as pentacyclic oxindole alkaloids, polyphenols, and sterols.
Alternate Names(s): Vilacora, Uncaria tomentosa
Legal Status: Available for OTC purchase in the United States.
Suggested Dose: There is currently no suggested dose for cat's claw supplementation.
Safety Considerations: Caution should be taken for those prescribed selective serotonin reuptake inhibitors (SSRIs), blood pressure medicines, anticoagulants, cancer medications, and/or antiretrovirals. Caution should also be taken for overall herb-drug interactions.
What Is Cat's Claw?
Cat's claw is a woody vine that grows in Central and South America. Cat's claw can modulate (change) the body's immune system. It is also believed to reduce free radicals (reactive, unstable molecules made by the body that can cause damage) in the body - a common culprit of inflammation.
Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.
A review of anti-inflammatory drugs and herbs found that medicinal plants, such as cat's claw, can aid in reducing or preventing inflammatory processes in the body.
Although further research is needed, this review also cited limited side effects from medicinal herbs, such as cat's claw, compared to commonly prescribed anti-inflammatory medicines.
Denture stomatitis is an inflammation of the mouth and gums caused by yeast overgrowth. It is a common complaint among denture wearers.
A small randomized study found that a 2% cat's claw gel was as effective in reducing the symptoms of denture stomatitis as the commonly prescribed miconazole gel.
Fatigue and Quality of Life in People With Cancer
A small study found that daily supplementation of 300 milligrams (mg) cat's claw extract reduced measures of fatigue and increased measures of quality of life for individuals with advanced tumors.
However, the supplementation did not show a reduction in tumor size or other measures of inflammation in the blood.
The following include other emerging uses for cat's claw. However, it is essential to note that there is little evidence backing the effectiveness of cat's claw in these conditions.
Pre-clinical, non-human studies have shown evidence that cat's claw extract may reduce cognitive decline in Alzheimer's by inhibiting the formation of plaques in the brain.
A cell study using cat's claw in human breast cancer tissue showed promising antitumor effects when used in conjunction with more traditional breast cancer treatments.
A separate study found that a particular active ingredient in cat's claw - quinovic acid glycoside - inhibited the growth of human bladder cancer cells by causing the death of those cells.
A study involving both glioblastoma (brain tumor) and bladder cancer cells found that a particular active ingredient in cat's claw - pentacyclic oxindole alkaloid - was harmful to the cancerous cells.
Some research has suggested that the active ingredients in cat's claw may be an effective adjunct treatment for COVID-19. However, these theoretical models are yet to be tested in human or animal populations.
Hypertension in Pregnancy
A non-human study found that supplementation with cat's claw reduced measures of hypertension (high blood pressure) in both pregnant and non-pregnant mice.
Additionally, cellular inflammation was decreased in human placental tissue when a cat's claw extract was applied.
There is no consensus on a safe internal dosage for cat's claw.
For external applications, 2% cat's claw extract gels were as effective against yeast overgrowth as 2% anti-fungal prescription gels.
Avoid cat’s claw if you're allergic to it or its components (parts).
Seek immediate medical attention if you have a severe allergic reaction (itching, hives, shortness of breath).
Serotonin syndrome: Cat's claw has been indicated in at least one case of serotonin syndrome (a dangerous build-up of serotonin in the body) in the United States. It is believed that one of the active ingredients in cat's claw may increase serotonin levels in the blood.
This can be dangerous for anyone taking prescribed medicine that is also meant to increase serotonin in the blood (such as SSRIs).
Dosages of cat's claw as low as 1% have been found to interact with various prescribed medications. It may interact with the following:
Antifungals: A 2% extract of cat's claw gel was as effective as a 2% miconazole gel for reducing candida (yeast) overgrowth in humans.
Antiretrovirals: A systematic review found that cat's claw significantly increased blood levels of antiretrovirals (medications that block human immunodeficiency virus, or HIV) for those taking such medicines. Individuals who are prescribed antiretrovirals should be monitored for any adverse side effects if they are also taking cat's claw.
Anticoagulants (blood-thinning medications): In a lab study using human cells, applying cat's claw extract reduced thrombin (which helps form clots). Individuals already taking prescribed medication that reduces clots should practice caution if supplementing with cat's claw.
Blood pressure medications: A non-human study found that supplementation with cat's claw reduced measures of high blood pressure in non-pregnant mice. Individuals already taking prescribed medication to reduce blood pressure should practice caution if supplementing with cat's claw.
Cancer medications: Due to emerging evidence regarding cat's claw and its antitumor effects, it is advised that those receiving cancer treatment should consult their healthcare provider before supplementing with cat's claw.
SSRIs: Cat's claw has been indicated in at least one case of serotonin syndrome in the United States. It is believed that one of the active ingredients in cat's claw may increase serotonin levels in the blood. If you are prescribed an SSRI, it is advised to consult with your healthcare provider before supplementing with cat's claw.
Herb-drug interactions: A 1% cat's claw extract preparation significantly reduced the effectiveness of cytochrome P450 - an essential enzyme that assists the body in metabolizing drugs. Additionally, cat's claw was found to activate the body's PX receptor, which also affects drug metabolism. Cat's claw may, therefore, impact many medications that use these pathways to be metabolized and excreted. Speak with your pharmacist if you need further information about your medications.
The following precautions should be taken with cat's claw:
Allergy: Avoid cat's claw if you're allergic to it or its components (parts).
Autoimmune conditions: There are no studies examining the effect of cat's claw on autoimmune conditions, specifically. However, cat's claw has many medication interactions. Caution should be applied in supplementing cat's claw for individuals who are immunocompromised.
Pregnancy: Studies on cat's claw and its potential effects on pregnancy have been conducted only with mouse models and human tissue samples. No studies have been conducted on pregnant people. Consult your healthcare provider before taking cat's claw.
Breastfeeding: No studies have examined the safety of cat's claw supplementation when breastfeeding. Consult your healthcare provider before incorporating cat's claw into your care.
Children: There are few studies examining cat's claw usage for children. Of those, studies have only been conducted on topical (on the skin) uses rather than internal preparation. Please consult your child's healthcare provider before including cat's claw in their care.
Serotonin syndrome: Cat's claw has been indicated in at least one case of serotonin syndrome in the United States. It is believed that one of the active ingredients in cat's claw may increase serotonin levels in the blood. This can be dangerous for anyone taking prescribed medicine that is also meant to increase serotonin in the blood (such as SSRIs).
Dietary supplements are not regulated like prescription medications in the United States. Therefore, some may be safer than others. When choosing a supplement, consider factors such as third-party testing, potential drug interactions, and other safety concerns. Talk to a healthcare provider or a registered dietitian nutritionist (RD or RDN) about supplement quality and safety.
Cat's claw is a plant native to the Amazon and has been commonly used as a folk medicine to treat many symptoms. There is some evidence that the active ingredients in cat's claw can reduce inflammation both internally and externally.
Care should be taken when supplementing with cat's claw, particularly for those prescribed SSRIs, blood pressure medicines, anticoagulants, cancer medications, and/or antiretrovirals. Caution should also be taken for overall herb-drug interactions.
Frequently Asked Questions
What is cat's claw good for?
Cat's claw is known for its anti-inflammatory effects, as well as its ability to modulate the body's immune system.
Cat's claw is also believed to reduce free radicals in the body - a common culprit of inflammation.
Does cat's claw kill viruses?
There is limited evidence that cat's claw, when used as a complement to other forms of treatment, can inhibit the replication of viruses, such as HIV.
This should not be taken to mean that cat's claw alone kills viruses or is a first-line treatment for viral infections.
Does cat's claw kill covid?
There is some research being done to suggest that the active ingredients in cat's claw may be an effective adjunct treatment for covid-19.
However, these theoretical models are yet to be tested in human or animal populations.
Read the original article on Verywell Health.