NutriDex

The Supplement Research Compendium
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Cat's Claw

Uncaria tomentosa

Amazonian anti-inflammatory vine with thin but real arthritis data.

Preliminary evidence ✨Joint & Skin🛡️Gut & Immune

✚ Updated · How we grade evidence

Evidence tier
Preliminary
Research weight
Citations
6 verified / 6
Classification
Joint & Skin
❝
What the evidence says. Graded preliminary: only a handful of small, mostly single-site human RCTs (n=40-45) show modest pain reductions in arthritis, with no replication, no large trials, and most mechanistic evidence coming from cell and animal studies rather than people. (Preliminary evidence: Early or small human trials; promising but not yet conclusive.)

What is Cat's Claw?

Cat's Claw (Uncaria tomentosa) is a joint and skin supplement used for ease joint pain. NutriDex grades the human evidence as Preliminary. Cat's claw is a woody South American vine (two species, Uncaria tomentosa and U. guianensis) traditionally used for inflammation and infection. The strongest human data are two small trials: a 4-week osteoarthritis study (n=45) where ~100 mg/day freeze-dried U. guianensis cut activity-related knee pain within a week (but not rest or night pain), and a 24-week rheumatoid-arthritis RCT (n=40, added to standard DMARDs) where a pentacyclic-alkaloid U. tomentosa extract reduced painful joints by 53% vs 24% on placebo. A small human study also suggested enhanced DNA repair. Animal meta-analyses show lower IL-6 and NF-kB but no consistent TNF-alpha effect. Trials are tiny, short, unreplicated, and species/extract-specific, so benefits are plausible but unproven. It is not a substitute for arthritis medication.

Purported Benefits

✓Ease joint pain
✓Rheumatoid arthritis support
✓Knee osteoarthritis pain
✓Anti-inflammatory
✓Immune modulation

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Rheumatoid arthritis joint pain (adjunct)Single 24-wk RCT (n=40) added to DMARDs cut painful joints 53% vs 24%; tiny and unreplicated. Preliminary ↑ benefit · moderate 1
Knee osteoarthritis painOne 4-wk RCT (n=45) reduced activity-related pain within a week but not rest/night pain; very small and short. Preliminary ↑ benefit · small 1
Anti-inflammatory (cytokine modulation)Animal meta-analysis lowered IL-6 and NF-kB but not TNF-a; preclinical only, no human inflammatory endpoints. Preliminary ↑ benefit 1
Enhanced DNA repair / immune modulationA single 8-wk study (n=12) suggested improved DNA repair; exploratory, clinical relevance unknown. Preliminary ↑ benefit 1

Dosing & Compounds

Typical Dose
Roughly 100 mg/day freeze-dried Uncaria guianensis for osteoarthritis, or ~60 mg/day of a pentacyclic-alkaloid Uncaria tomentosa extract for rheumatoid arthritis, as studied.
Active Compounds
Pentacyclic oxindole alkaloidsQuinovic acid glycosidesPolyphenols / proanthocyanidins

Safety & Cautions

Generally well tolerated short-term; the most common effects are nausea, diarrhea and stomach upset, and it has not been linked to liver injury. Because it inhibits CYP3A4, it can raise blood levels of drugs cleared by that pathway, including some HIV protease inhibitors, cyclosporine and certain benzodiazepines; it may also add to bleeding risk with anticoagulants/antiplatelets and to blood-pressure lowering. Avoid in pregnancy and breastfeeding, and use caution with autoimmune disease, organ transplants (immunosuppressants) and before surgery; rare reports include acute kidney injury in a lupus patient and worsened Parkinson's symptoms. Educational only — always check with your doctor or pharmacist before combining Cat's Claw with any medicine.

Cat's Claw drug interactions

Known or theoretical interactions between Cat's Claw and common medications — educational, not exhaustive. Always check with your doctor or pharmacist before combining Cat's Claw with any medicine.

Caution
Immunosuppressants (cyclosporine, tacrolimus, transplant)
May stimulate the immune system, potentially opposing immunosuppressant drugs and worsening autoimmune disease.
Cat's claw can make the immune system more active, which may counteract drugs intended to suppress immunity. NCCIH — Cat's Claw

Key Studies

Meta-analysis Arado 2024 ✓ Full text
Meta-analysis of 24 animal studies: extracts lowered IL-6 (SMD -0.72) and NF-kB (SMD -1.19) but not TNF-alpha; low toxicity. Preclinical only.
RCT Mur 2002 ✓ PubMed
24-wk RCT (n=40) added to DMARDs: U. tomentosa extract cut painful joints 53.2% vs 24.1% placebo (p=0.044); minor side effects only.
RCT Piscoya 2001 ✓ PubMed
4-wk RCT (n=45) of ~100 mg/day freeze-dried U. guianensis in knee OA: activity pain fell within 1 week; no change in rest/night pain; no liver or blood toxicity.
RCT Sheng 2001 ✓ PubMed
8-wk human study (n=12) of 250-350 mg/day aqueous extract enhanced DNA repair after induced damage; no serious adverse effects.
Safety LiverTox 2019 ✓ Full text
Cat's claw not linked to clinically apparent liver injury (likelihood score E); minor GI effects; inhibits CYP3A4 raising interaction potential.
Review Hardin 2007 ✓ PubMed
Review: cat's claw decreases osteoarthritis inflammation mainly via TNF-alpha inhibition and antioxidant action; human evidence limited.
6 sources cited · 6 verified Search all studies on PubMed ↗

Common questions about Cat's Claw

What is Cat's Claw used for?

Cat's Claw is most often taken for Ease joint pain, Rheumatoid arthritis support, Knee osteoarthritis pain, Anti-inflammatory. Amazonian anti-inflammatory vine with thin but real arthritis data.

Does Cat's Claw work — what does the evidence say?

Preliminary evidence. Early or small human trials; promising but not yet conclusive. Cat's claw is a woody South American vine (two species, Uncaria tomentosa and U. guianensis) traditionally used for inflammation and infection. The strongest human data are two small trials: a 4-week osteoarthritis study (n=45) where ~100 mg/day freeze-dried U. guianensis cut activity-related knee pain within a week (but not rest or night pain), and a 24-week rheumatoid-arthritis RCT (n=40, added to standard DMARDs) where a pentacyclic-alkaloid U. tomentosa extract reduced painful joints by 53% vs 24% on placebo. A small human study also suggested enhanced DNA repair. Animal meta-analyses show lower IL-6 and NF-kB but no consistent TNF-alpha effect. Trials are tiny, short, unreplicated, and species/extract-specific, so benefits are plausible but unproven. It is not a substitute for arthritis medication.

What is the typical dose of Cat's Claw?

Roughly 100 mg/day freeze-dried Uncaria guianensis for osteoarthritis, or ~60 mg/day of a pentacyclic-alkaloid Uncaria tomentosa extract for rheumatoid arthritis, as studied.

Is Cat's Claw safe? Any cautions or side effects?

Generally well tolerated short-term; the most common effects are nausea, diarrhea and stomach upset, and it has not been linked to liver injury. Because it inhibits CYP3A4, it can raise blood levels of drugs cleared by that pathway, including some HIV protease inhibitors, cyclosporine and certain benzodiazepines; it may also add to bleeding risk with anticoagulants/antiplatelets and to blood-pressure lowering. Avoid in pregnancy and breastfeeding, and use caution with autoimmune disease, organ transplants (immunosuppressants) and before surgery; rare reports include acute kidney injury in a lupus patient and worsened Parkinson's symptoms.

How many studies support Cat's Claw?

NutriDex cites 6 sources for Cat's Claw, graded "Preliminary".

Does Cat's Claw interact with any medications?

Yes — known or theoretical interactions include: Immunosuppressants (transplant / autoimmune) (caution). This is educational and not exhaustive; always check with your doctor or pharmacist before combining Cat's Claw with any medicine.

Cite this page
APA

Peh, D. (2026). Cat's Claw (Uncaria tomentosa): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/cats-claw

BibTeX
@misc{nutridex_cats_claw,
  author       = {Peh, Daryl},
  title        = {Cat's Claw (Uncaria tomentosa): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/cats-claw},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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