Home Ingredients Cat's Claw (Uncaria tomentosa)
Immune SupportJoint HealthAnti-Inflammatory

Cat's Claw (Uncaria tomentosa)

Uncaria tomentosa / guianensis
Evidence Level
Limited
1 Clinical Trial
4 Documented Benefits
2/5 Evidence Score

Cat's claw (Uña de Gato) is a large woody vine from the Amazon rainforest whose bark and root have been used by indigenous Peruvian peoples for centuries for immune support, inflammation, and infection. Its two main bioactive groups — pentacyclic oxindole alkaloids (POAs) and tetracyclic oxindole alkaloids (TOAs) — have opposing immune effects, requiring standardized POA-only extracts for consistent immune-enhancing results. Clinical evidence is limited but encouraging for rheumatoid arthritis and immune support applications.

Studied Dose 250–500 mg/day standardized POA extract; rheumatoid arthritis trials: 60 mg freeze-dried extract daily; traditional: 1–3 g/day bark decoction
Active Compound Pentacyclic oxindole alkaloids (POAs: uncarine F, mitraphylline, isomitraphylline) and glycosides — AC-11® (Natural Health Science) POA-standardized extract; avoid extracts with high TOA content

Benefits

Immune system modulation

Cat's claw POAs demonstrate immunomodulatory effects — stimulating phagocytosis, NK cell activity, and lymphocyte proliferation in laboratory and preliminary human studies. Traditional use for recurrent infections and immune deficiency has some mechanistic support, though large clinical trials are lacking.

Supported by Trial 1

Rheumatoid arthritis symptom reduction

A small but well-designed RCT (Phase II) showed freeze-dried cat's claw extract significantly reduced swollen joint count and patient-assessed pain vs. placebo in RA patients on standard therapy — with 53% reduction in swollen joints vs. 24% placebo. Larger confirmatory trials needed.

Supported by Trial 1

Anti-inflammatory and antioxidant activity

Cat's claw inhibits TNF-α production, NF-κB activation, and COX-2 expression in laboratory studies, and demonstrates antioxidant activity through direct free radical scavenging. These mechanisms support the traditional anti-inflammatory applications in arthritis and infection.

Supported by Trial 1

DNA repair support

AC-11® (a water-soluble cat's claw extract) has demonstrated DNA repair-enhancing activity in human cell studies — increasing nucleotide excision repair of UV-induced DNA damage. This novel mechanism has attracted interest for anti-aging and cancer prevention applications.

Supported by Trial 1

Mechanism of action

1

POA immunostimulation vs. TOA immunosuppression

Pentacyclic oxindole alkaloids (POAs) stimulate immune function via macrophage activation and lymphocyte proliferation. Tetracyclic oxindole alkaloids (TOAs) competitively antagonize POA immune-stimulating activity. High-quality POA-standardized extracts (with minimal TOAs) are required for consistent immune benefits — explains the inconsistent results seen with non-standardized products.

2

NF-κB and TNF-α inhibition

Cat's claw alkaloids and quinovic acid glycosides inhibit NF-κB nuclear translocation and reduce TNF-α production in macrophages and synovial cells — providing the anti-inflammatory mechanism relevant to rheumatoid arthritis and inflammatory conditions.

3

Nucleotide excision repair pathway enhancement

AC-11® extract enhances the cellular nucleotide excision repair (NER) pathway that removes UV-induced and chemically-damaged DNA bases. This DNA repair mechanism is being studied for applications in cancer chemoprevention and UV skin protection.

Clinical trials

1
Cat's Claw for Rheumatoid Arthritis — Phase II RCT
PubMed

Randomized, double-blind, placebo-controlled phase II trial of freeze-dried Uncaria tomentosa extract (60 mg/day, pentacyclic-oxindole-alkaloid chemotype) vs placebo in 40 patients with active rheumatoid arthritis on sulfasalazine or hydroxychloroquine. 24 weeks. (Mur et al. 2002, J Rheumatol)

40 RA patients on standard DMARDs. 24-week intervention.

Cat's claw group showed significantly reduced number of painful and swollen joints vs placebo (53% vs 24% reduction in painful joints). Patient-assessed pain improved. Mechanism via NF-κB inhibition by pentacyclic oxindole alkaloids (POAs). Note: small phase II trial — has not been followed by larger phase III confirmation. Important: tetracyclic oxindole alkaloid (TOA) chemotype of cat's claw is functionally different (potentially antagonistic to POA effects) — TOA-free POA-standardized extracts should be specified.

Side effects and drug interactions

Common Potential side effects

Generally well tolerated at standardized extract doses
GI effects (nausea, diarrhea) possible at high doses
Avoid during pregnancy — has been used traditionally to induce abortion at high doses

Important Drug interactions

Anticoagulants — cat's claw inhibits platelet aggregation; monitor with warfarin
Antihypertensive medications — mild blood pressure-lowering activity; monitor
Immunosuppressants — cat's claw stimulates immune function; may reduce cyclosporine/tacrolimus efficacy; avoid in transplant patients
CYP3A4 substrates — may inhibit CYP3A4; monitor medications with narrow therapeutic windows

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Frequently asked questions about Cat's Claw (Uncaria tomentosa)

What is cat's claw used for?

Cat's claw (Uncaria tomentosa) is a Peruvian vine used for immune support, joint comfort, and as an antioxidant and anti-inflammatory herb. It is popular for joint health and immune resilience.

What is cat's claw good for?

It is studied and traditionally used for easing joint discomfort (including in osteoarthritis and rheumatoid arthritis), supporting immune function, and antioxidant support. Its alkaloids are credited with these effects.

How much cat's claw should I take?

Studies use standardized extracts, often around 250 to 350 mg per day for joint support; follow product labeling. It is also used as a tea or tincture.

Is cat's claw safe?

It is generally well tolerated. Because it can stimulate the immune system, those with autoimmune conditions or on immunosuppressants should be cautious, and it may interact with blood thinners and blood-pressure drugs. Pregnant women should avoid it.

What is Cat's Claw?

Cat's claw (Uña de Gato) is a large woody vine from the Amazon rainforest whose bark and root have been used by indigenous Peruvian peoples for centuries for immune support, inflammation, and infection.

What is the recommended dosage of Cat's Claw?

The clinically studied dose is 250–500 mg/day standardized POA extract; rheumatoid arthritis trials: 60 mg freeze-dried extract daily; traditional: 1–3 g/day bark decoction Always follow the product label and check with a healthcare provider for personal advice.

Is Cat's Claw safe, and does it have side effects?

For most healthy adults, Cat's Claw is well tolerated at studied doses. Reported effects can include: Generally well tolerated at standardized extract doses GI effects (nausea, diarrhea) possible at high doses It may also interact with some medications. Cat's Claw is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Cat's Claw interact with any medications?

Possible interactions include: Anticoagulants — cat's claw inhibits platelet aggregation; monitor with warfarin Antihypertensive medications — mild blood pressure-lowering activity; monitor If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Cat's Claw?

NutraSmarts rates the evidence for Cat's Claw as Limited (2 out of 5). It is backed by 1 clinical trial and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Mur E, Hartig F, Eibl G, Schirmer M Randomized double blind trial of an extract from the pentacyclic alkaloid-chemotype of uncaria tomentosa for the treatment of rheumatoid arthritis. The Journal of Rheumatology. 2002;29(4):678-81..PubMedUsed to support: Human double-blind RCT of pentacyclic oxindole alkaloid (POA) extract of Uncaria tomentosa in rheumatoid arthritis patients showing significant reduction in painful joints vs placebo. Directly backs 'rheumatoid arthritis symptom reduction' claim.
  2. Sheng Y, Bryngelsson C, Pero RW Enhanced DNA repair, immune function and reduced toxicity of C-MED-100, a novel aqueous extract from Uncaria tomentosa. Journal of Ethnopharmacology. 2000;69(2):115-26. doi: 10.1016/s0378-8741(99)00070-7.PubMedUsed to support: In-vitro and rodent study (stated as such) showing Uncaria tomentosa aqueous extract (C-MED-100) enhanced DNA repair, improved immune function markers, and reduced toxicity. Mechanistic basis for 'DNA repair support' and 'immune system modulation' claims.
  3. Montserrat-de la Paz S, Garcia-Gimenez MD, Angeles Fernandez-Arche M, Bermudez B Mitraphylline inhibits lipopolysaccharide-mediated activation of primary human neutrophils. Phytomedicine. 2016;23(2):141-8. doi: 10.1016/j.phymed.2015.12.015.PubMedUsed to support: In-vitro study (stated as such) with primary human neutrophils demonstrating that mitraphylline, a key oxindole alkaloid from Uncaria tomentosa, inhibits LPS-induced neutrophil activation. Mechanistic support for 'anti-inflammatory activity' and 'immune system modulation' claims.