Cat's Claw

NutraPedia - Evidence-Based Supplement Research

Back to Table of Contents
Health Goals: immunity inflammation joints

Research Overview

Research on Cat’s Claw (Uncaria tomentosa) has most extensively examined immunomodulatory effects and basic safety/toxicology, largely using standardized extracts such as the water-soluble preparation C‑MED‑100. In the cited work, repeated oral dosing in rats for 8 weeks (10–80 mg/kg/day) or 4 weeks (160 mg/kg/day) focused on immune endpoints (e.g., phytohemagglutinin-stimulated lymphocyte proliferation and circulating white blood cell counts), alongside general toxicology measures (clinical signs, body/organ weights, and histopathology). A smaller translational component has also been explored, including limited human supplementation data and mechanistic endpoints related to DNA damage and repair following irradiation.

The strongest evidence from these abstracts supports that C‑MED‑100 can increase certain immune-related measures (notably elevated WBC counts and increased mitogen-stimulated lymphocyte proliferation) in rats at higher doses (40–80 mg/kg/day) and in a very small human volunteer sample at 5 mg/kg/day over 6 weeks. The same animal study also reports improved repair of radiation-induced DNA single- and double-strand breaks at an early post-irradiation time point, suggesting potential effects on cellular stress responses or DNA repair pathways under experimental conditions. Safety findings in rats are comparatively robust within the constraints of the study design: no symptomatic toxicity or organ pathology was observed with repeated dosing, and the reported acute oral LD50/maximum tolerated dose exceeded 8 g/kg.

Key gaps remain. Human evidence is preliminary due to extremely small sample sizes, short follow-up, and reliance on surrogate biomarkers (e.g., WBC counts) rather than clinically meaningful outcomes (infection rates, inflammatory disease activity, or patient-reported endpoints). More research is needed to confirm efficacy and safety in larger, randomized controlled trials; to clarify dose–response relationships and optimal formulations; and to determine whether immune changes reflect beneficial immunostimulation, nonspecific leukocytosis, or context-dependent effects (including potential risks in autoimmune disease, transplant recipients, or those on immunomodulatory therapies). Additional mechanistic work is also warranted to validate and contextualize the reported DNA repair findings, including replication across models, assessment of longer-term outcomes, and evaluation of potential interactions with radiation or chemotherapy.

1. What conditions has Cat's Claw been studied for?

  • Immune function / immunomodulation: Studied in rats for effects on lymphocyte proliferation (PHA-stimulated splenocyte proliferation) and white blood cell (WBC) counts after daily oral dosing for weeks.

  • Radiation-related DNA damage / DNA repair: Studied in rats for repair of DNA single-strand breaks (SSB) and double-strand breaks (DSB) after high-dose whole-body irradiation (12 Gy).

  • General safety/tolerability: Studied in rats for acute and subchronic toxicity (including LD50/MTD estimation and organ pathology) and in a very small human volunteer study for short-term tolerability and WBC changes.

2. Does it work in treating those conditions? Summarize the evidence.

  • Immune markers (animal evidence): In female W/Fu rats given a water-soluble extract of Uncaria tomentosa (C-MED-100) daily for 8 weeks, PHA-stimulated lymphocyte proliferation was significantly increased at 40 and 80 mg/kg. WBC counts were also significantly elevated at 40 and 80 mg/kg for 8 weeks, and at 160 mg/kg for 4 weeks (P < 0.05 vs controls).

  • Immune markers (human evidence, very limited): In four healthy adult males given C-MED-100 at 5 mg/kg daily for 6 weeks, WBC were significantly elevated (P < 0.05) and no toxicity was observed. This is not evidence of treatment for a disease, but suggests an effect on an immune marker in a tiny sample.

  • DNA repair after radiation (animal evidence): Rats treated with C-MED-100 showed significantly improved repair of DNA SSB and DSB measured 3 hours after 12 Gy whole-body irradiation (P < 0.05). This supports a potential radioprotective/repair-supporting effect in an animal model, but does not establish clinical benefit in humans.

  • Clinical treatment outcomes: The abstract provided does not report clinical endpoints (e.g., symptom improvement, disease remission) for any medical condition. The evidence here is limited to biomarkers (WBC, lymphocyte proliferation) and a mechanistic endpoint (DNA break repair) plus safety observations.

3. What health benefits does it have?

  • Immune system modulation (biomarker-level): Increased PHA-stimulated lymphocyte proliferation in rat splenocytes at higher doses (40–80 mg/kg for 8 weeks), suggesting enhanced responsiveness of immune cells under stimulation conditions.

  • Increased WBC counts: Significant WBC elevation in rats at 40–80 mg/kg for 8 weeks (and 160 mg/kg for 4 weeks) and in a small human study at 5 mg/kg for 6 weeks (P < 0.05). Whether this translates into fewer infections or better clinical outcomes is not addressed in the abstract.

  • Support of DNA damage repair after radiation (animal model): Improved repair of radiation-induced DNA SSB and DSB in rats, measured shortly after irradiation. This suggests a potential protective or recovery-supporting effect under extreme experimental conditions.

Important limitation: The abstract supports changes in laboratory measures, not proven prevention or treatment of specific diseases in humans.

4. Does it have any downsides or side effects?

  • Rats (subchronic dosing): No acute or chronic toxicity signs were observed symptomatically in rats treated daily with 10–80 mg/kg for 8 weeks or 160 mg/kg for 4 weeks. No changes were found in body weight, food consumption, organ weight, or pathology of kidney, liver, spleen, and heart attributed to treatment.

  • Rats (acute toxicity): The LD50 and maximum tolerated dose (MTD) for a single oral dose were reported as greater than 8 g/kg, suggesting low acute toxicity in this animal model.

  • Humans (very small sample): In four healthy adult males taking 5 mg/kg daily for 6 weeks, no toxicity was observed. However, the sample size is too small to reliably detect uncommon adverse effects.

  • Potential concern based on observed effects: WBC elevation occurred in both rats and humans. The abstract does not describe whether this was within normal ranges or associated with any symptoms, so the clinical significance (benefit vs risk) is unclear.

Overall, within the dosing and durations studied in this abstract, tolerability appeared good, but human safety conclusions are limited by the extremely small human study and lack of detailed adverse event reporting.

5. Is it beneficial or harmful for any genetic variations (pharmacogenomics)?

The provided abstract does not evaluate genetic variants, genotype-stratified responses, or pharmacogenomic interactions. No conclusions can be drawn from this evidence about whether Cat's Claw (C-MED-100) is beneficial or harmful for specific genetic variations.

References

  1. Enhanced DNA repair, immune function and reduced toxicity of C-MED-100, a novel aqueous extract from Uncaria tomentosa
    Y Sheng, C Bryngelsson, R W Pero (2000)


Want personalized supplement recommendations based on your genetics?
Upload Whole Genome Sequencing (WGS) raw DNA data today!
Or upload raw DNA data to get started with your free analysis!