Cat's Claw
Uncaria tomentosa
A South American vine bark from the Amazon with immune-modulating, anti-inflammatory, and DNA repair properties studied in arthritis and viral conditions.
What is Cat's Claw?
Cat's claw (Uncaria tomentosa) is a woody vine native to the Amazon rainforest and Central American tropics, named for the hook-like thorns on its stems. Indigenous Asháninka people have used the inner bark for centuries for infections, inflammation, and general health. Two chemotypes exist: pentacyclic oxindole alkaloid (POA) and tetracyclic oxindole alkaloid (TOA), with POA being the preferred therapeutic form as TOA may antagonize POA's immune-modulating effects.
Known Health Benefits
How It Works
Pentacyclic oxindole alkaloids (isopteropodine, pteropodine, isomitraphylline) modulate immune function by enhancing phagocytosis, increasing T-helper cell and macrophage activity, and modulating NF-κB signaling. Quinovic acid glycosides provide direct anti-inflammatory and antiviral activity. The alkaloids also inhibit TNF-α production and may enhance DNA repair mechanisms. AC-11, a water-extracted form, has shown specific DNA repair enhancement in human studies. The anti-inflammatory effect is COX-1 and COX-2 selective.
What Research Says
A 2002 RCT showed cat's claw reduced joint pain and swelling in rheumatoid arthritis patients taking conventional treatment. The AC-11 extract demonstrated enhanced DNA repair in a randomized trial measuring single-strand DNA breaks. Antiviral studies show activity against dengue virus, herpes simplex, and HIV (in vitro). A pilot study in osteoarthritis showed significant reduction in knee pain with 8 weeks of treatment. The herb is increasingly used in Lyme disease protocols in integrative medicine, though clinical trial evidence for this use is limited.
Active Compounds
Oxindole alkaloids (isopteropodine, pteropodine), quinovic acid glycosides
Forms & Bioavailability
Oxindole alkaloids are moderately well-absorbed orally. The POA chemotype should be selected over TOA for immune benefits. AC-11 is a water-soluble carboxy alkyl ester extract with different pharmacology (primarily DNA repair) than whole bark. Traditional preparation involves decoction (boiling bark for 30+ minutes). Standardized extracts provide consistent alkaloid dosing.
Dosage Guidance
| Use Case | Dosage |
|---|---|
| Immune support | 250–500 mg standardized extract daily |
| Arthritis / joint health | 500–1000 mg daily |
| DNA repair (AC-11) | 350 mg AC-11 daily |
| Bark decoction | 1–2 g inner bark simmered 15 min |
| Lyme disease protocol | 500–1000 mg 2–3x daily |
Always consult a healthcare provider for personalized dosing.
Potential Side Effects
GI upset; headache with initial use; not recommended in pregnancy or autoimmune conditions
Who Should Avoid It
- Autoimmune conditions (immune stimulation may worsen lupus, MS, RA flares)
- Pre- and post-organ transplant (interaction with immunosuppressants)
- Pregnancy and lactation (traditional contraceptive use suggests hormonal/uterine effects)
- Scheduled surgery (discontinue 2 weeks prior — anticoagulant effects)
- Concurrent anticoagulant therapy
- Leukemia (theoretical concern with immune stimulation)
Pregnancy & Lactation
Contraindicated in pregnancy. Indigenous use as a contraceptive suggests hormonal activity and potential to affect pregnancy. May have abortifacient properties at high doses. Insufficient safety data during lactation — avoid.
Known Drug Interactions
May interact with blood thinners, blood pressure medications, and immunosuppressants
Evidence Classification
Based on in vitro studies, animal models, pilot trials, or traditional use documentation. Clinical evidence is limited.
Frequently Asked Questions
What's the difference between POA and TOA chemotypes?
Cat's claw exists as two chemotypes based on alkaloid content. POA (pentacyclic oxindole alkaloid) is the preferred medicinal form with immune-modulating properties. TOA (tetracyclic oxindole alkaloid) may actually antagonize POA's immune benefits. Quality products specify 'POA chemotype' or 'TOA-free' on the label. Wild-harvested bark can be either chemotype, so standardization matters.
Can cat's claw help with Lyme disease?
Cat's claw is widely used in integrative Lyme disease protocols (notably by Drs. Lee Cowden and Stephen Buhner) for its immune-modulating and anti-inflammatory properties. While practitioner reports are positive, clinical trial evidence specifically for Lyme disease is lacking. It is typically used as part of a multi-herb protocol, not as a sole treatment.
Is cat's claw safe for people with autoimmune conditions?
Generally, cat's claw is avoided in autoimmune conditions because its immune-stimulating properties could worsen autoimmune flares. However, some practitioners note that its immunomodulatory (rather than purely immunostimulatory) effects might be beneficial in certain cases. If you have an autoimmune condition, use only under experienced practitioner guidance.
What is AC-11 and how does it differ from regular cat's claw?
AC-11 is a patented water-soluble carboxy alkyl ester extract from Uncaria tomentosa. Unlike whole bark extract, it has been specifically studied for DNA repair enhancement — reducing single-strand DNA breaks and improving cellular repair mechanisms. It does not contain the oxindole alkaloids found in regular cat's claw and has a different application profile (anti-aging, sun damage repair vs. immune modulation).
How does cat's claw compare to boswellia for joint inflammation?
Both are effective anti-inflammatories but work through different mechanisms. Boswellia primarily inhibits 5-lipoxygenase (5-LOX), while cat's claw targets NF-κB and COX pathways. Boswellia has more clinical trial evidence for osteoarthritis specifically. Cat's claw offers additional immune-modulating benefits. Some practitioners combine both for comprehensive joint support.
References
- Efficacy and safety of freeze-dried cat's claw in osteoarthritis of the knee: mechanisms of action of the species Uncaria guianensis. Piscoya J, Rodriguez Z, Bustamante SA, et al.. Inflamm Res (2001)View study
- Cat's claw (Uncaria tomentosa) inhibits TNFα production and enhances DNA repair in irradiated lymphocytes. Sheng Y, Bryngelsson C, Pero RW. J Ethnopharmacol (2000)View study
- Treatment of rheumatoid arthritis with a pentacyclic oxindole alkaloid-enriched cat's claw extract: a randomized controlled trial. Mur E, Hartig F, Eibl G, Schirmer M. J Rheumatol (2002)View study
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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.