tuneTypical Dose
250-350 mg/day standardized extract
Natural Compound
Cat's Claw
Uncaria tomentosa
Evidence TierCWADA NOT PROHIBITED
watchEffect Window
Weeks (most available human signal around 6 weeks).
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Cat's Claw has limited, extract-specific human evidence for immune-cell support, with moderate uncertainty and strong dependence on product standardization.
The human data for Cat's Claw are narrow and depend heavily on using the same standardized extract that was tested. Small C-MED-100 volunteer studies suggest modest white-blood-cell and DNA-repair effects, and one chemotherapy-adjunct trial in breast cancer reported less neutropenia while a similar colorectal-cancer trial was negative. That leaves Cat's Claw as an extract-specific supportive-care candidate, not a dependable immune booster or arthritis supplement for the general public.
Botanical extract with pentacyclic oxindole alkaloid and polyphenolic constituents linked to immune-modulating and anti-inflammatory activity. Clinical translation is limited and formulation-specific.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Small increase in white blood cell count in limited short-term human extract studies.
- Possible adjunct neutropenia-support signal in one chemotherapy context. Replication is mixed.
Secondary Outcomes
- Preclinical anti-inflammatory and leukocyte-survival pathway support.
- Clinical effects appear product- and context-dependent.
Safety
Contraindications and Interactions
Contraindications
- Pregnancy
- Lactation
- Known extract allergy
Side effects
- GI upset
- Headache
- Dizziness
Interactions
- Immunosuppressants
- Anticoagulants/antiplatelets
- Complex oncology regimens
Avoid if
- Autoimmune disease without clinician guidance
- Hormone-sensitive condition without clinician guidance
- High-risk polypharmacy
Evidence
Study-level References
cats-claw-SRC-001Small human volunteer substudy within a broader preclinical toxicity and immune-function paper
Sourceopen_in_newSheng Y, Bryngelsson C, Pero RW. Enhanced DNA repair, immune function and reduced toxicity of C-MED-100, a novel aqueous extract from Uncaria tomentosa. J Ethnopharmacol. 2000;69(2):115-126. doi:10.1016/S0378-8741(99)00070-7. PMID:10687868.
Population: Four healthy adult male volunteers.
Dose protocol: 350 mg/day C-MED-100 for 6 weeks.
Key findings: WBC increased ~8.7% (6.60 to 7.18 x10^9/L).
Notes: Very small sample and limited generalizability.
Paper content
This paper mostly reported rat immune, toxicity, and DNA-repair data, but it also included a tiny 6-week human volunteer substudy in 4 healthy adult men given the aqueous Cat's Claw extract C-MED-100. No toxicity was observed and white blood cell counts increased significantly after supplementation, roughly from 6.60 to 7.18 x10^9/L. The human signal is best treated as hypothesis-generating because the sample was extremely small, uncontrolled, and tied to a proprietary extract rather than to generic Cat's Claw products.
cats-claw-SRC-002Small randomized volunteer study
Sourceopen_in_newSheng Y, Li L, Holmgren K, Pero RW. DNA repair enhancement of aqueous extracts of Uncaria tomentosa in a human volunteer study. Phytomedicine. 2001;8(4):275-282. doi:10.1078/0944-7113-00045. PMID:11515717.
Population: Apparently healthy adults working in the same environment.
Dose protocol: 250-350 mg/day for 6 weeks.
Key findings: Reported leukocyte count increase over study period.
Notes: Limited external validity and extract-specific design.
Paper content
This 8-week volunteer study randomized 12 healthy adults to 250 mg/day or 350 mg/day of the proprietary aqueous Cat's Claw extract C-MED-100 or to a non-supplemented control group. The supplemented groups showed statistically significant decreases in hydrogen-peroxide-induced DNA damage together with increased DNA repair compared with controls, and there was also a directional increase in mitogen-induced lymphocyte proliferation. No drug-related toxicity was observed on symptoms, clinical chemistry, whole-blood analysis, or leukocyte differential counts. The study is richer than the earlier 4-person report, but it remains a very small proprietary-extract trial rather than a broadly generalizable efficacy study.
cats-claw-SRC-003Randomized clinical adjunct trial
Sourceopen_in_newSantos Araujo MC, Farias IL, Gutierres J, Dalmora SL, Flores N, Farias J, de Cruz I, Chiesa J, Morsch VM, Chitolina Schetinger MR. Uncaria tomentosa-Adjuvant Treatment for Breast Cancer: Clinical Trial. Evid Based Complement Alternat Med. 2012;2012:676984. doi:10.1155/2012/676984. PMID:22811748.
Population: Women with invasive ductal carcinoma stage II undergoing FAC chemotherapy.
Dose protocol: 300 mg/day (70% ethanolic extract, 2.57% pentacyclic oxindole alkaloids).
Key findings: Reduced degree of neutropenia and favorable immune-cell trajectory versus placebo.
Notes: Adjunct oncology setting with regimen-specific context.
Paper content
This randomized adjunct trial evaluated 300 mg/day of standardized oral Uncaria tomentosa alongside FAC chemotherapy in women with stage II invasive ductal breast cancer. Across the six chemotherapy cycles, the Cat's Claw group showed less neutropenia and lower cellular DNA damage than the chemotherapy-only control group. The result is clinically more relevant than the tiny healthy-volunteer studies because it tested a real supportive-care setting, but it remains regimen-specific and tied to a particular standardized extract rather than to generic Cat's Claw products.
cats-claw-SRC-004Randomized clinical adjunct trial
Sourceopen_in_newFarias IL, Araujo MC, Farias JG, Rossato LV, Elsenbach LI, Dalmora SL, Flores NM, Durigon M, Cruz IB, Morsch VM, Schetinger MR. Uncaria tomentosa for Reducing Side Effects Caused by Chemotherapy in CRC Patients: Clinical Trial. Evid Based Complement Alternat Med. 2012;2012:892182. doi:10.1155/2012/892182. PMID:21869902.
Population: Colorectal-cancer patients receiving FOLFOX4 chemotherapy.
Dose protocol: 300 mg/day.
Key findings: Non-significant neutrophil trend. No robust signal across earlier cycles.
Notes: Limited sample and null main signal.
Paper content
This randomized colorectal-cancer supportive-care trial tested 300 mg/day of Uncaria tomentosa alongside FOLFOX4 chemotherapy in 43 patients. Unlike the positive breast-cancer adjunct study, this trial found no meaningful changes in hemograms, oxidative-stress markers, immunologic parameters, or adverse effects across the six treatment cycles. That negative result is important because it shows the chemotherapy-support signal is inconsistent and may depend on cancer setting, regimen, or extract specifics rather than representing a dependable class effect.
cats-claw-SRC-005Human clinical trial.
Sourceopen_in_newPiscoya J, et al. Efficacy and safety of freeze-dried cat's claw in osteoarthritis of the knee: mechanisms of action of the species Uncaria guianensis. Inflamm Res. 2001. PMID:11603848.
Population: Knee OA participants.
Dose protocol: Freeze-dried Uncaria guianensis preparation.
Key findings: Contextual symptom and safety data, species-specific.
Notes: Species and formulation differ from many tomentosa products.
Paper content
Contextual symptom and safety data, species-specific.
cats-claw-SRC-006In vitro.
Sourceopen_in_newSalazar EL, Jayme V. Depletion of specific binding sites for estrogen receptor by Uncaria tomentosa. Proc West Pharmacol Soc. 1998. PMID:9836266.
Population: Estrogen-receptor binding model.
Dose protocol: 10-20 ug exposure range.
Key findings: Noncompetitive inhibition signal in vitro.
Notes: In vitro mechanism only. Not direct clinical efficacy evidence.
Paper content
Noncompetitive inhibition signal in vitro.
cats-claw-SRC-007Preclinical animal study.
Sourceopen_in_newNogueira Neto J, et al. Contraceptive effect of Uncaria tomentosa in rats with experimental endometriosis. Acta Cir Bras. 2011. PMID:22030809.
Population: Rat endometriosis model.
Dose protocol: 2.8-4.0 mg/kg.
Key findings: Hormonal/reproductive effects in animal model.
Notes: Supports pregnancy caution. Does not establish human contraceptive efficacy.
Paper content
Hormonal/reproductive effects in animal model.
cats-claw-SRC-008Preclinical.
Sourceopen_in_newRojas-Duran R, et al. Anti-inflammatory activity of Mitraphylline isolated from Uncaria tomentosa bark. J Ethnopharmacol. 2012. PMID:22846434.
Population: LPS-challenged murine model.
Dose protocol: Mitraphylline 30 mg/kg for 3 days.
Key findings: Reduced inflammatory cytokines in model system.
Notes: Mechanistic support. Indirect for clinical outcomes.
Paper content
Reduced inflammatory cytokines in model system.
cats-claw-SRC-009Randomized, double-blind, placebo-controlled trial with open-label extension.
Sourceopen_in_newMur 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. J Rheumatol. 2002;29(4):678-681. PMID:11950006.
Population: Patients with active rheumatoid arthritis receiving sulfasalazine or hydroxychloroquine.
Dose protocol: Pentacyclic alkaloid-chemotype extract vs placebo for 24 weeks (n=40).
Key findings: Painful joint count reduced 53.2% vs 24.1% (P=0.044). Improvements in swollen joints in open-label phase.
Notes: Only double-blind RA trial with cat's claw. Small sample but controlled design.
Paper content
This double-blind RCT tested a pentacyclic alkaloid-chemotype extract of Uncaria tomentosa in 40 patients with active rheumatoid arthritis already on sulfasalazine or hydroxychloroquine. After 24 weeks, the extract group showed a significantly greater reduction in painful joints (53.2% vs 24.1%, P=0.044) compared to placebo. Improvements in swollen joints and Ritchie Index were observed during the subsequent 28-week open-label phase. The study provides modest evidence of analgesic benefit in RA when used as an adjunct to conventional therapy, though the small sample size and open-label extension limit confidence.
cats-claw-SRC-010Phase II prospective clinical trial.
Sourceopen_in_newde Paula LC, Fonseca F, Perazzo F, Cruz FM, Cubero D, et al. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30. doi:10.1089/acm.2014.0127. PMID:25495394.
Population: Patients with advanced solid tumors without further therapeutic options.
Dose protocol: 100 mg U. tomentosa extract three times daily (n=51).
Key findings: Improved quality of life and social functioning, reduced fatigue in advanced cancer patients.
Notes: Phase II open-label trial. Relevant for adjunctive quality-of-life support in oncology.
Paper content
This Phase II trial evaluated 100 mg of Uncaria tomentosa dry extract taken three times daily in 51 patients with advanced solid tumors who had no remaining standard treatment options. The study found improvements in overall quality of life and social functioning, along with reduced fatigue. Four participants achieved disease stabilization lasting over 8 months. No significant changes in inflammatory markers were observed. The trial is limited by its open-label, single-arm design, but it provides a signal that cat's claw may improve subjective wellbeing in palliative oncology settings.