It is certainly commonplace now in society to check with various internet sites (WebMD etc.) when dealing with health issues, unfamiliar ingredients, diet and how they all intersect. Often they can be helpful, but at times they are a collage of misinformation, misperceptions , errors and speculation. As I am the scientist who spent a lot of time in the Amazon Rainforest and whose discoveries as to how Cat’s claw works led to an Innovation Award at the NIH, let me help guide you through this.

Who Writes These Articles

The authors are not noted, as they may be several individuals as the public contributes. Rarely is it the scientists who did the research. Often the authors are pharmacists or related healthcare providers but again, not the scientists that did the research.  Certainly, MDs and clinics contribute but even these can be peripherally associated.

Blood Pressure

Like a bad rumor that refuses to stop, there are reports that Cat’s claw could causes LOW blood pressure (hypotension) and should not be used in those with low blood pressure or taking anti-hypertensive pharmaceuticals.

In clinical trials with cat’s claw there is ZERO evidence of it causing hypotension. Further, there is no evidence that there are any studies that show this action. In a word it is purely “conjecture”. 

If one uses PubMed to search for the two terms “cat’s claw” and “hypertension” one gets three citations. One shows benefits in pregnancy induced hypertension. The other two are preclinical (lab and rat based) and both are supporting beneficial actions.

AMLODIPINE is a drug used for managing cardiovascular health and there is speculation that cat’s claw may affect the blood levels of the drug because they may share pathways of liver metabolism. As such warnings are issued.

This is all theoretical, there are no studies that show and altered pharmacokinetics of drugs metabolized by CYP 3A4. If there were studies to prove this, they would be cited, and the language would not be “might interfere” but rather “will interfere”.

Pharmacists are often guilty of taking such evidence out of context. Their training is draw attention to theoretical complications, but they do not take these speculations all the way through to clinical trials where implications are tested.

Similarly, the FTC rejects pre-clinical research as a means of substantiation for a supplement. They demand clinical trials to support a marketing claim, otherwise it is dismissed as speculation and not verifiable. The same standards must apply when issuing warnings and concerns over dietary components, natural products or supplements.

Blood Clotting

Aspirin works by “killing” (via irreversible acetylation) the enzyme COX1 in platelets, limiting their ability to form clots. Platelets can form clots by COX independent means, but aspirin certainly prolongs bleeding. None of that is true for cat’s claw, as it has no impact on COX nor other mechanisms affecting blood coagulation. 

Usually the pre-clinical (lab) studies that drive this misinterpretation involve doses that would never be achieved with a supplement or normal ingestion. While they may be demonstrable in the lab the results have no relevance to the clinical state i.e., intact human. A prime example is a study look at fibrin formation in test tubes, where incredibly high doses of cat’s claw have marginal effects on fibrin formation. However, none of this has any relevance to the intact human at normal dosing, nor is there any evidence to say it does. More conjecture I am afraid.

Indeed, my own research has shown that cat’s claw is an effective therapeutic to limit the damage to the intestinal tract caused by NSAIDs (NSAID-enteropathy).