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Dietary supplement

Whole Herb Cat's Claw 500 mg Ingredients & Drug Interactions

by Mason Natural

Whole Herb Cat's Claw 500 mg label
See full label image
Capsule Category: Botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Whole Herb Cat's Claw 500 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Whole Herb Cat's Claw 500 mg is a dietary supplement by Mason Natural with 1 active ingredient. Its ingredients are commonly taken for osteoarthritis and rheumatoid arthritis, inflammation, immune support.Based on those ingredients, 962 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Cat's Claw. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Whole Herb Cat's Claw 500 mg by Mason Natural

Ask about any prescription or over-the-counter medication and we check it for interactions with Whole Herb Cat's Claw 500 mg by Mason Natural — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Whole Herb Cat's Claw 500 mg by Mason Natural

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: Cat's Claw 500 mg per capsule. Cat's claw is a woody vine from the Amazon rainforest that contains alkaloids — compounds that make up its active chemistry.

The capsule itself is made from gelatin, with magnesium stearate and silica added as inactive ingredients to help with manufacturing.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Cat's Claw's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: Support immune health.
  • We looked for evidence on: Inflammatory bowel disease (IBD), Osteoarthritis, Rheumatoid arthritis (RA), Immune function, Inflammation, General wellness.
  • The closest evidence on file: Cat's Claw is rated "Insufficient Reliable Evidence To Rate" for Inflammatory bowel disease (IBD) (Natural Medicines).
  • Also on file: Cat's Claw is rated "Insufficient Reliable Evidence To Rate" for Osteoarthritis, Rheumatoid arthritis (RA).

The evidence for cat's claw isn't well established in our data. We hold insufficient reliable evidence to rate it for allergic rhinitis (hay fever), Alzheimer disease, asthma, osteoporosis, cancer, and chronic fatigue syndrome — the conditions it's most commonly used for.

That doesn't mean it doesn't work; it means the clinical trials we have aren't strong enough yet to say either way. Talk with your pharmacist or doctor about whether cat's claw makes sense for what you're targeting.

The evidence, ingredient by ingredient Cat's Claw

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Cat's claw is generally well tolerated in the short term for healthy adults, but we don't have good data on long-term safety. In one clinical study of patients with advanced cancer, a small number experienced anemia, low white blood cell counts (leukopenia), and low platelet counts (thrombocytopenia), though it's unclear whether the supplement or their disease caused these.

A few case reports link cat's claw to kidney injury, including acute kidney failure in one patient with lupus and acute interstitial nephritis in another. Headache, fatigue, insomnia, and nerve pain (neuropathy) were also reported in that same cancer study at low rates.

Don't take cat's claw during pregnancy — it has a traditional history as an abortifacient (something used to end pregnancy), and safety data is lacking. Avoid it while breastfeeding as well, because there isn't enough information to know if it's safe for your baby.

Side effects, ingredient by ingredient Cat's Claw

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Cat's Claw.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs.
  • For scale: 963 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before you take this, double-check with your pharmacist if you're on blood thinners or antiplatelet drugs like warfarin, aspirin, or clopidogrel (Moderate risk of increased bleeding). Blood pressure medications and calcium channel blockers also need review (Moderate risk of low blood pressure).

Let us know about any drugs your liver metabolizes, immunosuppressants, and especially if you're taking Paxlovid for COVID-19. No interactions are documented for the ingredients we could check beyond those listed here, but that's not a guarantee none exist.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

Cat's claw may appeal if you're looking for an herbal option for immune support or general wellness, but the evidence for specific health claims is weak. Because it interacts with blood thinners, blood pressure drugs, liver-metabolized medications, and immunosuppressants, you should check your exact prescriptions with us before starting.

Skip it if you're pregnant, breastfeeding, or planning surgery. Talk with your pharmacist about whether it's right for you.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Feb 26, 2020.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Whole Herb Cat's Claw 500 mg, straight from the product label.

Brand Mason Natural
Barcode (UPC) 311845113351
Net contents 60 Capsule(s)
Market status On market
Date entered into DSLD Feb 26, 2020
DSLD ID 214043
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Whole Herb Cat's Claw 500 mg by Mason Natural, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
UPC/BARCODE
311845113351
IngredientAmount% DV
Cat's Claw500 mg--

Other ingredients: Gelatin, Magnesium Stearate, Silica

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Seals/Symbols

Mason Guarantee Laboratory Tested cGMP Certified Good Manufacturing Practice Certified

General Statements

Mason Natural Est. 1967

Formulation

May support immune health

Color variation is possible.

Guaranteed no added: Sugar, starch, soy, sodium, yeast, corn, wheat, dairy, fish, tree nuts, peanuts, egg, fragrances, artificial colors, flavors, preservatives, crustacean/shellfish.

Gluten-free Soy free

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Directions: Adults - Take one capsule, one to two times daily, preferably with food, as a dietary supplement.

Formula

Contains naturally harvested herbal products.

FDA Disclaimer Statement

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Precautions

Warning: If you are pregnant, nursing, taking any medications or planning any medical procedure, consult your physician before use.

Discontinue use and consult your physician if any adverse reactions occur.

Keep out of reach of children.

Tamper-evident seal: Do not use product if seal appears tampered.

Storage

Store in a dry place under controlled room temperature: 20 degrees - 25 degrees C (68 degrees - 77 degrees F).

Brand IP Statement(s)

Mason Natural is a registered trademark and does not refer to any product or ingredient claim.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Whole Herb Cat's Claw 500 mg by Mason Natural label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Whole Herb Cat's Claw 500 mg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Whole Herb Cat's Claw 500 mg by Mason Natural

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule Amounts shown are per serving.

Cat's Claw

Interacts with
962 drugs
500 mg per serving

Cat's claw is a South American vine traditionally used for inflammation, joint pain, and immune support. Some small studies hint it may help with arth...

Cat's Claw monograph & interactions

Other (inactive) ingredients: Gelatin, Magnesium Stearate, Silica. These complete the product’s ingredient list but are not active constituents.

Interaction report

Whole Herb Cat's Claw 500 mg by Mason Natural Drug Interactions

Want to check YOUR meds against Whole Herb Cat's Claw 500 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
962Drugs
962 Moderate

Ingredients driving the most interactions

Cat's Claw 962

Individual Drug Interactions

The ingredients in Whole Herb Cat's Claw 500 mg interact with 962 drugs. Click any drug to see the details.

1 of the 1 ingredient in Whole Herb Cat's Claw 500 mg interact with drugs. Each result below shows which ingredient is responsible. Cat's Claw

Each ingredient & the kinds of drugs it affects

For each ingredient in Whole Herb Cat's Claw 500 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Cat's Claw6 drug types · 962 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, cat's claw may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Cat's claw contains rhynchophylline and isorhynchophylline. Animal research suggests that these alkaloids can inhibit platelet aggregation. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Antihypertensive Drugs

Theoretically, taking cat's claw with antihypertensive drugs might increase the risk of hypotension.
Cat's claw contains rhynchophylline. In vitro and animal research suggests that rhynchophylline can lower blood pressure. This interaction has not been reported in humans.

Likelihood Probable Evidence D
Calcium Channel Blockers

Theoretically, taking cat's claw with calcium channel blockers might increase the risk of hypotension.
Cat's claw contains various alkaloids, including rhynchophylline, isorhynchophylline, corynoxeine, and isocorynoxiene. Animal research suggests that these alkaloids can lower blood pressure by acting as calcium channel blockers. This interaction has not been reported in humans.

Likelihood Probable Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.
Cat's claw may affect the clearance of drugs metabolized by CYP3A4. In vitro research shows that cat's claw can inhibit CYP3A4 enzymes. In one case report, a patient taking cat's claw (at an unspecified dose) experienced increased serum levels of atazanavir, ritonavir, and saquinavir, all of which are CYP3A4 substrates. Levels returned to normal 15 days after discontinuation of the cat's claw supplement, suggesting inhibition of CYP3A4 by cat's claw. In contrast, animal research suggests that rhynchophylline, an alkaloid contained in cat's claw, induces CYP3A expression and accelerates the metabolism of nirmatrelvir, the active component in the nirmatrelvir/ritonavir combination product.

Likelihood Possible Evidence D
Immunosuppressants

Theoretically, cat's claw might interfere with immunosuppressive therapy.
In human and laboratory research, cat's claw has been shown to have immunostimulating activity. It stimulates phagocytosis and increases respiratory cellular activity and the mobility of leukocytes. Theoretically, this could interfere with the activity of immunosuppressant medications.

Likelihood Possible Evidence D
Nirmatrelvir/Ritonavir (Paxlovid)

Theoretically, cat's claw may decrease the levels of nirmatrelvir.
Cat's claw contains rhynchophylline. Animal research suggests that this alkaloid induces CYP3A expression, thereby accelerating the metabolism of nirmatrelvir, the active component in the nirmatrelvir/ritonavir combination product. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Cat's Claw full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Whole Herb Cat's Claw 500 mg, from the product label.

Mason Natural

See all Mason Natural products
Name
Mason Vitamins, Inc.
City
Miami Lakes
State
FL
ZipCode
33014
Phone Number
1-888-860-5376
Web Address
www.MasonVitamins.com
Pharmacist Counseling Corner

Whole Herb Cat's Claw 500 mg by Mason Natural: Common Questions

Does Whole Herb Cat's Claw 500 mg by Mason Natural interact with any medications?
Yes. Based on its ingredients, Whole Herb Cat's Claw 500 mg has a known interaction with 962 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Whole Herb Cat's Claw 500 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is cat's claw safe to take while I'm pregnant?
No, you should avoid it during pregnancy. Cat's claw has a traditional history of being used to end pregnancy, and we don't have safety data to say it's okay. Talk with your doctor before using any supplement while pregnant.
Can I breastfeed while taking cat's claw?
No, we don't have enough safety information to know whether it passes into breast milk or could affect your baby. Avoid it while breastfeeding and talk with your doctor or pharmacist about safer options.
What's rhynchophylline and why does it matter?
It's an alkaloid — a natural compound — in cat's claw that animal research suggests can lower blood pressure and affect blood clotting. That's why we flag interactions with blood pressure drugs and blood thinners.
How long is it safe to take cat's claw?
Short-term use in healthy adults is generally well tolerated, but we don't have good data on what happens with long-term daily use. If you're thinking about taking it regularly, ask your pharmacist about a safe timeline for you.
Does cat's claw actually work for what it claims?
The evidence isn't strong enough yet to say. We hold insufficient reliable evidence for the main uses people buy it for — allergies, Alzheimer disease, asthma, osteoporosis, cancer, and chronic fatigue. That doesn't mean it won't help, just that we need better studies.
What side effects have been reported?
In one study of cancer patients, a small number had low blood counts, headache, fatigue, insomnia, and nerve pain. A few rare case reports link cat's claw to kidney injury. These are uncommon, but important to know if you have kidney disease or a weakened immune system.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if Whole Herb Cat's Claw 500 mg is safe with your meds?

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Whole Herb Cat's Claw 500 mg label
Go deeper

The Full Monographs Behind Whole Herb Cat's Claw 500 mg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Cat's Claw

Interacts with 962 drugs

Cat's claw is a South American vine traditionally used for inflammation, joint pain, and immune support. Some small studies hint it may help with arthritis symptoms, but the overall evidence...

Read the full Cat's Claw monograph →
Sources

Sources & How We Checked

Whole Herb Cat's Claw 500 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 16 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Cat's Claw 16 references
  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  3. Sandoval M, Charbonnet RM, Okuhama NN, et al. Cat's claw inhibits TNFalpha production and scavenges free radicals: role in cytoprotection. Free Radic Biol Med 2000;29:71-78.
  4. Müller AC, Kanfer I. Potential pharmacokinetic interactions between antiretrovirals and medicinal plants used as complementary and African traditional medicines. Biopharm Drug Dispos. 2011;32(8):458-70. PubMed
  5. Sheng, Y., Bryngelsson, C., and Pero, R. W. 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. PubMed
  6. Lamm, S., Sheng, Y., and Pero, R. W. Persistent response to pneumococcal vaccine in individuals supplemented with a novel water soluble extract of Uncaria tomentosa, C-Med-100. Phytomedicine 2001;8(4):267-274.
  7. Sheng, Y., Li, L., Holmgren, K., and Pero, R. W. DNA repair enhancement of aqueous extracts of Uncaria tomentosa in a human volunteer study. Phytomedicine 2001;8(4):275-282.
  8. Chen, C. X., Jin, R. M., Li, Y. K., Zhong, J., Yue, L., Chen, S. C., and Zhou, J. Y. Inhibitory effect of rhynchophylline on platelet aggregation and thrombosis. Zhongguo Yao Li Xue.Bao. 1992;13(2):126-130.
  9. Flythe, J. E., Rueda, J. F., Riscoe, M. K., and Watnick, S. Silicate nephrolithiasis after ingestion of supplements containing silica dioxide. Am.J.Kidney Dis. 2009;54(1):127-130. PubMed
  10. Zhou, J. and Zhou, S. Antihypertensive and neuroprotective activities of rhynchophylline: the role of rhynchophylline in neurotransmission and ion channel activity. J.Ethnopharmacol. 10-28-2010;132(1):15-27. PubMed
  11. Zhou, J. Y. and Zhou, S. W. Isorhynchophylline: A plant alkaloid with therapeutic potential for cardiovascular and central nervous system diseases. Fitoterapia 2012;83(4):617-626. PubMed
  12. Hemingway, S. R. and Phillipson, J. D. Proceedings: Alkaloids from S. American species of Uncaria (Rubiaceae). J.Pharm.Pharmacol. 1974;26 Suppl:113P.
  13. Hilepo, J. N., Bellucci, A. G., and Mossey, R. T. Acute renal failure caused by 'cat's claw' herbal remedy in a patient with systemic lupus erythematosus. Nephron 1997;77(3):361. PubMed
  14. De Paula LCL, Fonseca F, Perazzo F, 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.
  15. Portalatin G, Shettigar S, Carrion-Rodriguez A, et al. Ketogenic-Diet Shake Containing Uncaria tomentosa-Associated Acute Interstitial Nephritis. Case Rep Nephrol Dial 2022;12(3):219-225.
  16. Lei S, Guo A, Lu J, et al. Activation of PXR causes drug interactions with Paxlovid in transgenic mice. Acta Pharm Sin B 2023;13(11):4502-4510. PubMed

See these in context on the Cat's Claw monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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