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Cat's Claw (Uncaria tomentosa)
Oxindole alkaloids from Amazon vine modulate immune function and reduce inflammation — studied for osteoarthritis and rheumatoid arthritis.
What the evidence says
Studies are split: Cat's Claw helped in 1 of 3 cases, with the rest inconclusive or showing no benefit.
Most evidence is from high-quality meta-analyses and randomised trials published 2000–2025 with a typical study size of 40 participants.
Based on 33 studies · 1 meta-analysis · 4 RCTs · 280 total participants
Confidence
ModerateWhat the studies found
By outcome
Cat's Claw has an evidence score of 8/10 — strong evidence based on 33 indexed studies, including 1 meta-analysis. Oxindole alkaloids from Amazon vine modulate immune function and reduce inflammation — studied for osteoarthritis and rheumatoid arthritis.
The commonly studied dose of Cat's Claw is 250-350mg standardized extract or 1-3g dried bark, 2-3x daily. Research points to an estimated optimal dose around 350mg, with a minimum effective dose near 250mg. Individual response varies — start low and adjust.
The best time to take Cat's Claw is with meals. Taking it with food is preferred. Cat's claw (Uncaria tomentosa) contains oxindole alkaloids, quinovic acid glycosides, and polyphenols with immune-modulating and anti-inflammatory properties.
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Last reviewed May 2026 · evidence from 38 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Cat's Claw is a woody vine from the Amazon rainforest named for its hook-like thorns. Used by indigenous peoples for millennia, it contains oxindole alkaloids and other compounds with immune-modulating, anti-inflammatory, and antioxidant effects. Research supports benefits for osteoarthritis, rheumatoid arthritis, and immune function.
Enhances and regulates immune function
Reduces inflammatory mediators
Protects against oxidative damage
How Cat's Claw works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
250-350mg standardized extract or 1-3g dried bark, 2-3x daily
Take with food
| Form | Type |
|---|---|
| 💊Standardized extract (3% oxindole alkaloids) | Recommended |
| 💊Dried bark capsules | Alternative |
| 🍵Tea | Alternative |
| 💧Tincture | Alternative |
Two species exist — Uncaria tomentosa is most researched. Some products use U. guianensis.
Minimum: 4 weeks
Optimal: 12 weeks
Cycling: 8-12 weeks on, 2-4 weeks off recommended for long-term use.
Note: Taking with food reduces potential GI upset. Split into 2-3 doses for best results.
Based on systematic review evidence showing significant pain reduction in knee osteoarthritis. Limited number of direct RCTs. Most studies used 250-350mg doses. GI upset more common at higher doses.
Reduced arthritis symptoms
Improved immune function
Lower inflammatory markers
Avoid — traditionally contraindicated
Avoid or use under medical supervision
May increase bleeding risk
May counteract immunosuppression
May have additive blood pressure lowering effects
May affect drug metabolism
Tip: Take with food
Tip: Reduce dose
Tip: Usually resolves
Cat's Claw is generally safe at recommended doses, with a few precautions worth noting. The most commonly reported side effects are GI upset, dizziness, headache. Use caution if any of these apply to you: Autoimmune diseases (may stimulate immune system); Before surgery (stop 2 weeks prior); Organ transplant recipients.
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