Amazonian vine with solid evidence for arthritis and inflammation. Well-studied safety profile (52-week trials), but narrow therapeutic focus and important drug interactions.
Traditions: Amazonian indigenous medicine, Western herbalism (modern adoption)
Multiple traditions agree on use.
Traditional name 'savéntaro' (powerful plant). Used for arthritis, rheumatism, gastric ulcers, infections, wounds, asthma, and fevers. Bark decocted as tea.
WHO Monographs document indigenous Amazonian uses for musculoskeletal conditions, gastrointestinal issues, infections, respiratory conditions, and women's health.
Adopted based on Amazonian ethnobotany. Focus on immune modulation, arthritis, inflammation, and cancer supportive care.
Cat's claw has consistent evidence for arthritis and inflammation, with the longest safety trial (52 weeks) of any anti-inflammatory herb. Effects are modest but reliable. The evidence is narrow - it does a few things well rather than being a broad-spectrum remedy. Notably, therapeutic activity appears independent of alkaloid content, suggesting whole-extract benefits.
40 patients, 52 weeks. Painful joints reduced 53.2% vs 24.1% placebo (p=0.044) at 24 weeks. Phase 2 showed reduction in painful joints (p=0.003), swollen joints (p=0.007), Ritchie Index (p=0.004). Only minor side effects.
45 patients, 4 weeks. Pain associated with activity significantly reduced. Benefits observed within first week. No deleterious effects on blood or liver function vs placebo.
24 studies. Statistically significant reductions in IL-6 (SMD -0.72, p=0.001) and NF-κB (SMD -1.19, p=0.001). Extracts showed low toxicity.
51 patients with advanced solid tumors. Quality of life improved (p=0.0411), social functioning improved (p=0.0341), fatigue reduced (p=0.0496). No tumor response.
Most studied preparation. POA (pentacyclic oxindole alkaloid) chemotype preferred, TOA <0.02%. Standardized to 8-10% carboxy alkyl esters. Hydroalcoholic extracts superior to aqueous for anti-inflammatory effects.
Taste: Woody, slightly bitter, earthy. Not particularly unpleasant compared to many medicinal barks.
Traditional Amazonian preparation. Simmer 10-15 minutes. Aqueous extracts less potent than hydroalcoholic for anti-inflammatory effects but still traditional.
40-60% alcohol for optimal alkaloid extraction. Traditional herbalist preparation, but standardized extracts have more clinical validation.
Cat’s claw represents a focused success story in herbal medicine - it does a few things well with solid evidence, rather than claiming broad-spectrum benefits.
Strong evidence (RCTs and meta-analyses):
Moderate evidence:
Notable finding: Therapeutic activity appears independent of alkaloid content [6]. The alkaloid-depleted and alkaloid-rich fractions showed comparable anti-inflammatory effects, suggesting polyphenols, carboxy alkyl esters, or other constituents drive the benefits.
What it doesn’t do: No tumor response in cancer trials (improves quality of life but doesn’t affect tumor size) [4]. Colorectal cancer chemotherapy adjuvant trial was negative [7].
Ashaninka Indians (Peru, Amazon basin):
WHO-documented indigenous uses:
Not part of classical systems: Cat’s claw is NOT documented in Ayurveda, Traditional Chinese Medicine, or classical European herbalism. This is purely an Amazonian traditional medicine adopted by Western herbalism in the late 20th century based on ethnobotanical research.
Modern Western adoption (post-1980s):
Convergence: The traditional Amazonian use for arthritis and rheumatism is strongly validated by modern RCTs. The 52-week RA trial and 4-week OA trial confirm what indigenous healers observed for centuries.
Standardized extracts (most convenient, most studied):
The clinical trials used POA-rich (pentacyclic oxindole alkaloid) extracts with strict specifications:
| Condition | Extract Type | Dose | Frequency |
|---|---|---|---|
| Rheumatoid arthritis | POA chemotype, TOA <0.02% | 30-60mg | Once daily |
| Osteoarthritis | Freeze-dried extract | Varies | Daily |
| Cancer supportive care | Dry extract | 100mg | 3x daily (300mg total) |
Quality markers to look for:
Traditional tea (full-spectrum, less potent):
Tincture (traditional herbalist approach):
Week 1-2: 30-60mg extract OR 1/2 tsp bark tea once daily
Week 3-4: Continue at initial dose OR increase to 100mg once daily
Week 5-8: If needed, split dose to 100mg 2-3x daily (similar to cancer trial dosing)
Don’t expect immediate dramatic results. This is a modest but reliable effect that builds over time.
Baseline (1 week before starting):
During trial (weeks 1-8): Track the same markers daily or weekly. Compare:
For cancer supportive care (if applicable):
STOP if you notice:
What they report: Reduced joint pain (especially with activity), less morning stiffness, improved range of motion, reduced swelling. In cancer patients: less fatigue, better social functioning, improved quality of life.
Cat’s claw tea tastes woody, slightly bitter, and earthy. It’s not particularly unpleasant compared to many medicinal barks - think mild tree bark flavor. Not as aggressively bitter as goldenseal or as challenging as ashwagandha.
If you can’t tolerate the tea, standardized extracts in capsules are clinically validated and work well (actually better for anti-inflammatory effects).
The species problem: Two species are used - Uncaria tomentosa and Uncaria guianensis. Both show activity. U. guianensis demonstrated superior potency in all antioxidant assays (p<0.01) and stronger TNF-alpha inhibition (IC50 9.5 ng/mL vs 14.1 ng/mL, p<0.01) despite having 35-fold less alkaloid content than U. tomentosa [6]. This confirms that alkaloids aren’t the primary active constituents.
What to look for:
Extraction method matters: Hydroalcoholic extracts showed significantly superior anti-inflammatory activity vs aqueous extracts (p<0.05) [8]. The mechanism doesn’t involve COX-1 or COX-2 inhibition - it works through alternative pathways.
Critical finding: Cytotoxic effects vary considerably depending on extraction method and chemical composition [9]. Standardization isn’t just for consistency - it’s for safety and efficacy.
This is a reliable, narrow-spectrum tool for inflammatory arthritis with unusually strong safety data (52-week trial, no hepatotoxicity, LiverTox Score E).
When it works: Modest but consistent reduction in joint pain and swelling, especially pain associated with activity. Benefits may appear within first week for OA, or build over 8-24 weeks for RA. In cancer care, improves quality of life and reduces fatigue without affecting tumors.
What makes it special: The 52-week safety trial is exceptional among anti-inflammatory herbs. Most herbal trials run 4-12 weeks. Having a full year of safety data, combined with no hepatotoxicity across 200+ patients, makes this one of the safest well-studied anti-inflammatory herbs.
The drug interaction problem: CYP 3A4 inhibition is a real concern. If you’re on medications metabolized via this pathway (very common - statins, blood pressure meds, many others), talk to your prescriber first. For immunosuppressants, this is an absolute contraindication.
Who should try it: RA or OA patients looking for an adjunct to conventional therapy, or those who can’t tolerate NSAIDs. Cancer patients seeking quality of life improvement (with oncologist approval). Those with chronic inflammatory conditions who want something with strong safety data.
Start low (30-60mg extract or 1/2 tsp tea once daily), give it 4 weeks minimum (8-24 weeks for RA), track joint pain and function honestly, respect the CYP 3A4 interaction. This isn’t going to revolutionize your arthritis, but you may notice 30-50% reduction in painful joints based on the RCT data - and that’s meaningful.
Duration: Minimum 4 weeks for osteoarthritis (benefits may appear within first week). 8-24 weeks for rheumatoid arthritis. Up to 52 weeks studied safely.
What to notice:
Start with lower dose: 30-60mg extract OR 1/2 tsp bark tea once daily. Increase gradually over 2 weeks to standard dose if tolerated. For osteoarthritis, benefits may appear within first week. For RA, give it 4-8 weeks minimum. Half-life is short (0.6-4.4 hours), so divided dosing (2-3x daily) may be more effective than once daily, though once-daily dosing worked in RA trials. Can take with or without food; if GI upset occurs, take with food.
Generally considered: safe
Contraindications:
Pregnancy/Nursing: Contraindicated in pregnancy and breastfeeding due to insufficient safety data. WHO guidelines recommend avoiding use.
Excellent safety profile overall. LiverTox Score E (unlikely cause of liver injury) - no hepatotoxicity documented in clinical trials [LiverTox]. No serious adverse events across 200+ patients in trials [1][2][4]. Minor GI side effects (nausea, upset, diarrhea) uncommon. CRITICAL DRUG INTERACTION: Inhibits CYP 3A4 [LiverTox] - may increase levels of medications metabolized via this pathway (statins, calcium channel blockers, benzodiazepines, immunosuppressants, chemotherapy agents). Particularly concerning for narrow therapeutic index drugs. Safe duration: up to 52 weeks studied in RA trial [1]. Generally considered possibly safe for up to 6 months for most people. Long-term use (>6 months) has limited data. Can be used safely with conventional DMARDs (sulfasalazine, hydroxychloroquine) based on 52-week combination trial [1].