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Dietary supplement

Cat's Claw Ingredients & Drug Interactions

by Pure Encapsulations

Cat's Claw 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 Cat's Claw 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

Cat's Claw is a dietary supplement by Pure Encapsulations 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 Inner Vine Bark Extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Cat's Claw by Pure Encapsulations

Ask about any prescription or over-the-counter medication and we check it for interactions with Cat's Claw by Pure Encapsulations — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Cat's Claw by Pure Encapsulations

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 12, 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 Inner Vine Bark Extract. The remaining ingredients—cellulose, water, and ascorbyl palmitate—are inactive excipients that form the capsule and preserve the supplement.

Does it work?

Couldn't assess
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 assessable

This is a single-ingredient Cat's Claw product and its label doesn't state a use — see Cat's Claw's own graded uses on its monograph.

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.

The evidence we hold doesn't establish that cat's claw works for the conditions listed on the label—allergic rhinitis, Alzheimer disease, asthma, osteoporosis, cancer, and chronic fatigue syndrome. For all of these, the data shows insufficient reliable evidence to rate its effectiveness.

That doesn't mean it doesn't help; it means the research isn't yet solid enough for us to say.

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 short-term use by healthy adults, but long-term safety hasn't been well studied. One clinical trial in patients with advanced solid tumors reported anemia in 12% of participants and leukopenia (low white blood cells) and thrombocytopenia (low platelets) each in 2%—though because there was no placebo group and these patients had serious disease, we can't be sure cat's claw caused it.

Several case reports link cat's claw to kidney injury, including one case of acute kidney failure that improved when the supplement was stopped. Headache, fatigue, insomnia, and neuropathy (nerve damage) were also reported in that trial at low rates.

During pregnancy, safety data advises against cat's claw because of its traditional use as an abortifacient and lack of modern safety research. Similarly, there isn't enough data to know if it's safe while breastfeeding, so it's best to avoid it then too.

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.

Double-check this supplement before you start if you take blood pressure medications, calcium channel blockers, blood thinners (anticoagulants or antiplatelet drugs), immunosuppressants, or Paxlovid. All are Moderate-severity interactions.

Additionally, if you take any medication broken down by the liver enzyme CYP3A4, cat's claw may change how your body clears it—your pharmacist can help you identify those.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Cat's Claw may appeal to people looking for immune or anti-inflammatory support, but the evidence for its marketed uses isn't solid. If you take blood pressure drugs, blood thinners, immune suppressants, or antivirals, check your medications with the tool on this page before starting.

Pregnant or breastfeeding? Skip it.

Talk to your pharmacist if you're considering it, especially if you have a history of kidney disease.

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 Jul 18, 2023.

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 Cat's Claw, straight from the product label.

Brand Pure Encapsulations
Barcode (UPC) 766298005621
Net contents 180 Capsule(s)
Market status On market
Date entered into DSLD Jul 18, 2023
DSLD ID 295503
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Women (not pregnant or lactating), 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 Cat's Claw by Pure Encapsulations, 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)
Servings per container
180
UPC/BARCODE
766298005621
IngredientAmount% DV
Cat's Claw Inner Vine Bark Extract450 mg--

Other ingredients: Cellulose, Water, Ascorbyl Palmitate

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.
Storage

Store in a cool, dry place.

Suggested/Recommended/Usage/Directions

Recommendations: As with any dietary supplement, take 1 capsule, 1-3 times daily, with meals, or as directed by a health professional.

Precautions

Warning: Not to be taken by pregnant or lactating women. If you have any health condition or are taking any medication, consult your health professional before use.

Keep out of the reach of children.

Use only if safety seal is intact.

General Statements

Contents may not fill package in order to accommodate required labeling. Please rely on stated quantity. Scan to learn about our hypoallergenic supplements

Formulation

Certified gluten-free by the Gluten-Free Certification Organization, www.gluten.org

Supports joint, immune, cardiovascular and gastrointestinal function Gluten-free, non-GMO & hypoallergenic

Gluten-free, non-GMO & hypoallergenic

Seals/Symbols

GFCO.org (Gluten-Free Certification Organization)

FDA Statement of Identity

Dietary Supplement

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.

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

See for yourself

Cat's Claw by Pure Encapsulations label

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

Cat's Claw 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 Cat's Claw by Pure Encapsulations

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

Serving size1 Capsule(s) Dosage formCapsule Servings per container180 Amounts shown are per serving.

Cat's Claw Inner Vine Bark Extract

Interacts with
962 drugs
450 mg per serving Form: Uncaria tomentosa Inner Vine Bark Extract, Oxindole Alkaloids

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 Inner Vine Bark Extract monograph & interactions

Other (inactive) ingredients: Cellulose, Water, Ascorbyl Palmitate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Cat's Claw by Pure Encapsulations Drug Interactions

Want to check YOUR meds against Cat's Claw?

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 Inner Vine Bark Extract 962

Individual Drug Interactions

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

1 of the 1 ingredient in Cat's Claw interact with drugs. Each result below shows which ingredient is responsible. Cat's Claw Inner Vine Bark Extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Cat's Claw 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 Claw Inner Vine Bark Extract6 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 Inner Vine Bark Extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Cat's Claw, from the product label.

Pure Encapsulations

See all Pure Encapsulations products
Name
Pure Encapsulations
Street Address
490 Boston Post Road
City
Sudbury
State
MA
Phone Number
1-800-753-2277
Web Address
www.PureEncapsulations.com
Pharmacist Counseling Corner

Cat's Claw by Pure Encapsulations: Common Questions

Does Cat's Claw by Pure Encapsulations interact with any medications?
Yes. Based on its ingredients, Cat's Claw 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?
Cat's Claw 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 during pregnancy or breastfeeding?
No. During pregnancy, the safety data advises against it because of its traditional use as an abortifacient and lack of modern safety research. While breastfeeding, there isn't enough information to know if it's safe, so you should avoid it then too. Talk to your OB or midwife if you're thinking about it.
Does cat's claw really work for allergies, asthma, or the other conditions on the label?
The evidence we hold shows insufficient reliable data to say whether it works for allergic rhinitis, asthma, Alzheimer disease, osteoporosis, cancer, or chronic fatigue syndrome. That means research hasn't yet been solid enough to establish it, not that it doesn't help—but we can't claim it does based on what we know.
What side effects might I notice?
Cat's claw is generally well tolerated short-term, but long-term safety isn't well studied. One trial reported anemia, low white blood cells, low platelets, headache, fatigue, insomnia, and nerve damage at low rates—though the patients in that study had advanced cancer, so it's unclear what was due to the supplement. Case reports have linked cat's claw to kidney injury, so if you have kidney disease, be especially cautious.
How many active ingredients are in this product?
One: Cat's Claw Inner Vine Bark Extract. The other three ingredients—cellulose, water, and ascorbyl palmitate—are inactive fillers and preservatives.
Can I take this with my blood pressure medication?
Probably not without checking first. Cat's claw may lower blood pressure on its own, so combining it with blood pressure drugs or calcium channel blockers could theoretically drop your pressure too far. Use the medication checker on this page with your exact drug name, and talk to your pharmacist.
Will cat's claw interfere with my blood thinner?
It might. Animal research suggests cat's claw can slow blood clotting, so taking it alongside blood thinners or antiplatelet drugs like aspirin could theoretically increase bleeding risk. Check your medication with our tool and ask your pharmacist before starting.

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

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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.

Cat's Claw label
Go deeper

The Full Monographs Behind Cat's Claw’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

Cat's Claw'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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