What is Cat's Claw?
Cat's claw is a woody, high-climbing tropical vine native to the Amazon rainforest and other tropical areas of Central and South America. The vine can grow up to 100 feet tall, using hook-like thorns that resemble a cat's claws to climb trees.
Two Main Species:
Uncaria tomentosa: Most commonly used in the United States
Uncaria guianensis: More popular in Europe
Both the inner bark and root have been used for centuries in South American traditional medicine.
Important: Do not confuse cat's claw with "cat's foot" or "devil's claw" - these are entirely different plants.
Active Compounds & Mechanism of Action
Primary Active Ingredients:
Oxindole Alkaloids (most studied):
Pentacyclic oxindole alkaloids (POAs): Pteropodine, isopteropodine, mitraphylline, uncarine F
Tetracyclic oxindole alkaloids (TOAs): Different chemical structure
Other Important Compounds:
Quinovic acid glycosides
Triterpenes
Polyphenols and proanthocyanidins
Flavonoids
Tannins
Catechins
Rhynchophylline
Beta-sitosterol
How It Works:
Anti-Inflammatory Action:
Inhibits NF-kappa B signaling pathway
Reduces TNF-alpha (tumor necrosis factor) production
Decreases production of inflammatory cytokines (IL-1α, IL-1β, IL-4, IL-17)
Immune Modulation:
Stimulates white blood cell production
Enhances phagocytic activity (immune cells that engulf pathogens)
Increases T-helper cell function
Can both boost and calm the immune system as needed
Antioxidant Effects:
Scavenges free radicals
Protects against oxidative stress
May enhance DNA repair mechanisms
Cardiovascular Effects:
Inhibits platelet aggregation
May lower blood pressure
Reduces blood clotting tendency
Primary Functions & Benefits
Evidence-Supported Benefits:
Osteoarthritis:
Reduces pain during physical activity
May decrease stiffness and improve joint function
Effects typically seen within 1-4 weeks
Rheumatoid Arthritis:
Reduces number of painful and swollen joints when used with conventional medications
Shows modest but statistically significant improvement
Immune System Support:
Increases white blood cell count
May help fight infections more effectively
Shown to enhance immune response before vaccination
DNA Repair & Protection:
Enhances cellular DNA repair mechanisms
Protects skin cells from UV damage
May reduce DNA damage from chemotherapy
Chemotherapy Side Effects:
May reduce chemotherapy-induced white blood cell depletion
Could improve quality of life in cancer patients
Helps protect against cellular damage
Traditional & Preliminary Uses:
Digestive Health:
Traditionally used for gastric ulcers
May reduce inflammation in digestive tract
Used for diverticulitis, colitis, and gastritis
Other Claimed Benefits (limited evidence):
Viral infections (herpes, HPV)
Lyme disease symptoms
High blood pressure
Chronic fatigue
Wound healing
Skin conditions
Note: Many popular claims lack sufficient scientific evidence from well-designed human studies.
Recommended Daily Amounts
Standard Dosages:
Dried Bark Extract:
20-350 mg daily (WHO recommendation)
Usually divided into 2-3 doses throughout the day
Capsules:
300-500 mg daily
Typically in divided doses
Standardized Extract:
100-300 mg daily of extract containing 8-10% carboxy alkyl esters
Less than 0.5% oxindole alkaloids
Clinical Study Doses:
Osteoarthritis: 100 mg daily for 4 weeks
Rheumatoid arthritis: 60 mg daily for 24 weeks
Immune support: 700 mg daily for 2 months
DNA repair: 250-350 mg daily for 8 weeks
Traditional Tea: 1 gram of root bark, 2-3 times daily, boiled into decoction
Duration:
Most studies: 8-24 weeks
Generally considered safe for up to 6 months
Long-term safety beyond 6 months is unknown
How to Take Cat's Claw
Available Forms:
Capsules/tablets (most common)
Liquid extracts/tinctures
Powdered bark
Traditional tea (decoction from bark or root)
Topical creams/gels
Timing & Administration:
With or Without Food:
Can be taken with or without food
If stomach upset occurs, take with meals
No specific requirement for fat absorption (unlike fat-soluble vitamins)
Time of Day:
No specific time is best
For multiple daily doses, spread evenly throughout the day (morning, afternoon, evening)
Consistency matters more than timing
Duration of Use:
Minimum 4-8 weeks to see benefits for arthritis
Effects may take several weeks to manifest
Not intended as acute/immediate relief medication
Synergistic Supplements
May Work Well With:
For Joint Health:
Glucosamine sulfate
Chondroitin
MSM (methylsulfonylmethane)
Turmeric/curcumin
Omega-3 fatty acids
For Immune Support:
Vitamin C
Vitamin D
Zinc
Echinacea (though also immune-stimulating)
For Anti-Inflammatory Effects:
Ginger
Boswellia
Quercetin
Note: Some studies tested cat's claw combined with maca root or mineral supplements, showing synergistic benefits.
Critical Interactions & What NOT to Take
AVOID Combining With:
Blood Thinners/Anticoagulants - MAJOR INTERACTION:
Warfarin (Coumadin)
Heparin
Aspirin (acetylsalicylic acid)
Clopidogrel (Plavix)
Other antiplatelet drugs
Risk: Increased bleeding and bruising
Blood Pressure Medications - MODERATE INTERACTION:
Any antihypertensive drugs
Risk: Blood pressure may drop too low
Monitor blood pressure closely if combining
Immunosuppressants - MAJOR INTERACTION:
Drugs used after organ transplants (cyclosporine, tacrolimus)
Azathioprine
Corticosteroids
Chemotherapy drugs
Risk: Cat's claw may counteract immunosuppressive effects
Medications Metabolized by CYP3A4:
May alter drug levels by affecting liver metabolism
Examples: Some statins (lovastatin), antifungals (ketoconazole), some antihistamines (fexofenadine)
HIV/AIDS Medications:
May increase blood levels of antiretroviral drugs
Examples: Ritonavir, atazanavir, saquinavir, nelfinavir
Can also potentially decrease effectiveness of nirmatrelvir (Paxlovid component)
Birth Control Pills:
May interfere with hormonal contraceptives
Traditional use included contraceptive effects
Supplements to Use Cautiously With:
Other Blood Pressure-Lowering Supplements:
Coenzyme Q10 (CoQ10)
L-arginine
Fish oil
Casein protein
Stinging nettle
Risk: Additive blood pressure-lowering effects
Who Should Take Cat's Claw
Ideal Candidates:
Arthritis Sufferers:
People with osteoarthritis experiencing joint pain
Rheumatoid arthritis patients (as adjunct to conventional treatment)
Those seeking natural anti-inflammatory support
Immune System Support:
Individuals with frequent infections
Those looking to enhance general immune function
People recovering from illness (with medical supervision)
Digestive Issues:
People with inflammatory bowel conditions
Those with gastritis or ulcers (traditionally used)
Individuals with gut inflammation
Chemotherapy Patients:
May benefit from DNA protection (only under oncologist supervision)
Could help maintain white blood cell counts
General Wellness Seekers:
Those interested in traditional Amazonian medicine
People looking for antioxidant support
Individuals seeking natural anti-inflammatory options
Who Should AVOID or Use Extreme Caution
Absolute Contraindications:
Pregnant Women:
Possibly unsafe - may cause miscarriage or birth defects
Traditionally used as contraceptive and abortifacient
DO NOT USE during pregnancy
Breastfeeding Women:
Insufficient safety data
Unknown if active compounds pass into breast milk
AVOID use while breastfeeding
Children:
No safety data available for pediatric use
One study suggested it may stimulate pediatric leukemia cells
DO NOT give to children
Scheduled for Surgery:
STOP at least 2 weeks before surgery
Increases bleeding risk
May interfere with blood pressure control during surgery
Use Only Under Medical Supervision:
Autoimmune Diseases:
Multiple sclerosis (MS)
Lupus (SLE)
Rheumatoid arthritis (if using alone without conventional treatment)
Psoriasis
Risk: May overstimulate immune system, worsening symptoms
Kidney Disease or Problems:
Case reports of acute kidney injury
Risk of kidney stone formation (silicate nephrolithiasis)
Consult nephrologist before use
Liver Disease:
May affect liver enzyme function
Potential for herb-drug interactions via liver metabolism
Bleeding Disorders:
Hemophilia
Von Willebrand disease
Any clotting disorder
Risk: Increased bleeding tendency
Low Blood Pressure (Hypotension):
May lower blood pressure further
Can cause dizziness or fainting
Parkinson's Disease:
One case report of worsened symptoms
May worsen tremors or movement problems
Leukemia or Blood Cancers:
Preliminary data suggests may stimulate certain cancer cells
Requires oncologist approval
Taking Multiple Medications:
High potential for drug interactions
Always consult healthcare provider
Deficiency Symptoms
Not Applicable: Cat's claw is not an essential nutrient, so there is no deficiency state. It's a botanical supplement used therapeutically, not a vitamin or mineral the body requires for normal function.
Toxicity Symptoms
Mild Side Effects (Most Common):
Gastrointestinal Issues:
Nausea
Diarrhea
Stomach upset or discomfort
Abdominal cramping
These are most common with high doses or high-tannin preparations
Other Mild Effects:
Dizziness
Headache
Mild allergic reactions (itching, rash)
Serious/Rare Adverse Effects:
Renal Effects:
Acute kidney injury (case reports)
Silicate kidney stones
Symptoms: Flank pain, blood in urine, decreased urination
Neurological:
Neuropathy (nerve damage)
Worsening of Parkinson's symptoms
Symptoms: Tingling, numbness, increased tremors
Cardiovascular:
Significant blood pressure drops
Slow heart rate
Symptoms: Severe dizziness, fainting, weakness
Hormonal Effects:
May decrease progesterone or estrogen levels
Anti-estrogenic effects in some cases
Increased Bleeding Risk:
Especially when combined with anticoagulants
Symptoms: Easy bruising, prolonged bleeding, blood in stool/urine
Liver Toxicity (very rare):
While generally not hepatotoxic, some cases reported in multi-ingredient supplements
Symptoms: Jaundice, dark urine, abdominal pain, fatigue
What to Do If Toxicity Suspected:
Stop taking cat's claw immediately
Contact healthcare provider or poison control (1-800-222-1222)
Seek emergency care for severe symptoms
Special Considerations
Quality & Safety Concerns:
Supplement Contamination:
Herbal supplements not tightly regulated by FDA
Risk of contamination with heavy metals, pesticides, or other drugs
Some products may contain wrong species or adulterants
Solution: Purchase only from reputable manufacturers with third-party testing (USP, NSF, or GMP certification)
Species Differences:
Uncaria tomentosa vs. Uncaria guianensis:
U. guianensis may be more potent for antioxidant effects
U. tomentosa has 35-fold higher alkaloid content
Both used interchangeably in South America, but effects may differ
Check product label for species used
Extract Types:
Standard Extracts:
Variable alkaloid content
May contain both pentacyclic and tetracyclic alkaloids
AC-11 Extract (specialized):
Water-extracted from inner bark
Free of harmful alkaloid levels
Contains 6-8% carboxy alkyl esters (CAEs)
Standardized and clinically studied
Considered superior for anti-aging and DNA repair
Typical dose: 350 mg daily
TOA-Free Extracts:
Contain only pentacyclic oxindole alkaloids (POAs)
Free of tetracyclic oxindole alkaloids (TOAs)
May be preferred for rheumatoid arthritis
Some evidence POAs and TOAs have different/opposing effects
Traditional Preparation:
Indigenous peoples traditionally used cat's claw as:
Boiled decoction (tea) from bark or root
Consumed regularly (every 1-2 weeks) as disease prevention
General health tonic and immune support
Treatment taken over extended periods, not acute use
Drug Testing Considerations:
No known false positives on standard drug tests
Not a controlled substance
However, quality issues mean products could theoretically be contaminated
Summary & Key Takeaways
Cat's claw is a traditional Amazonian botanical with promising anti-inflammatory and immune-modulating properties. The strongest evidence supports its use for osteoarthritis and rheumatoid arthritis, with emerging research on immune support and DNA protection.
The Bottom Line:
Potential Benefits: May help reduce arthritis pain, support immune function, and provide antioxidant protection. Some evidence for helping cancer patients manage chemotherapy side effects.
Safety Profile: Generally well-tolerated for short-term use (up to 6 months), but serious interactions exist with blood thinners, immunosuppressants, and blood pressure medications.
Who Should Consider: Adults with arthritis seeking natural anti-inflammatory support, those wanting immune system enhancement, or individuals interested in traditional botanical medicine.
Who Should Avoid: Pregnant/breastfeeding women, children, people with autoimmune diseases, those on blood thinners or immunosuppressants, anyone scheduled for surgery, and individuals with kidney problems.
Quality Matters: Purchase from reputable manufacturers with third-party testing. Look for standardized extracts (AC-11 or POA-only extracts may be superior).
Realistic Expectations: Effects take several weeks to manifest. Not a quick fix. Best used as part of comprehensive health approach, not replacement for conventional treatment.
Always Consult Your Healthcare Provider: Especially critical if taking any medications, have chronic health conditions, or are considering it for serious health issues like cancer or autoimmune disease.
Final Note:
While cat's claw has centuries of traditional use and promising preliminary research, many of its claimed benefits lack robust scientific evidence from large, well-designed human clinical trials. More research is needed to fully understand its efficacy, optimal dosing, long-term safety, and exact mechanisms of action.