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Dietary supplement

Cat's Claw 1,000 mg Ingredients & Drug Interactions

by Nature's Answer

Cat's Claw 1,000 mg label
See full label image
Liquid 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 1,000 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

Cat's Claw 1,000 mg is a dietary supplement by Nature's Answer 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 (Uncaria tomentosa) inner 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 1,000 mg by Nature's Answer

Ask about any prescription or over-the-counter medication and we check it for interactions with Cat's Claw 1,000 mg by Nature's Answer — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Cat's Claw 1,000 mg by Nature's Answer

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 bark extract (from Uncaria tomentosa) at 1,000 mg per serving. It's a liquid delivered in purified water with organic alcohol as a preservative.

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.

We don't have enough reliable evidence to rate cat's claw for any of the conditions listed on the label — allergic rhinitis (hay fever), Alzheimer disease, asthma, osteoporosis, cancer, or chronic fatigue syndrome. That doesn't mean it doesn't work; it means the data we have isn't strong enough yet to say one way or the other.

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 long-term safety hasn't been well studied. The safety data advises against using it during pregnancy because of traditional use as an abortifacient and lack of safety research.

You should also avoid it while breastfeeding due to insufficient information. In one clinical trial, a small number of participants experienced blood-related side effects like anemia, low white blood cells (leukopenia), and low platelets (thrombocytopenia), though the patients had advanced cancers and it's unclear whether cat's claw caused these or the disease itself did.

Several case reports have linked cat's claw to kidney injury; if you have lupus or any history of kidney problems, talk with your pharmacist before starting.

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.

Check your medications against cat's claw before you start, especially if you take blood thinners (anticoagulants or antiplatelet drugs), blood pressure medications (antihypertensives or calcium channel blockers), Paxlovid (nirmatrelvir/ritonavir), or immunosuppressants. Also flag any drug that your liver processes via the CYP3A4 pathway.

The search tool on this page can help you verify your specific prescriptions.

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 is an herbal extract that may help with several conditions, but the evidence isn't strong enough to confirm it yet. If you take blood pressure medications, blood thinners, liver-metabolized drugs, Paxlovid, or immunosuppressants, check with your pharmacist first — the interaction data is significant.

Avoid it in pregnancy and while breastfeeding.

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 Jun 24, 2016.

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 1,000 mg, straight from the product label.

Brand Nature's Answer
Barcode (UPC) 083000001918
Net contents 2 fl. Oz.; 60 mL
Market status On market
Date entered into DSLD Jun 24, 2016
DSLD ID 60502
Product type Botanical
Supplement form Liquid
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Kosher, 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 1,000 mg by Nature's Answer, 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 mL
Maximum serving Sizes:
1 mL
Servings per container
60
UPC/BARCODE
083000001918
IngredientAmount% DV
Cat’s Claw (Uncaria tomentosa) inner bark extract1000 mg--

Other ingredients: purified Water, 24-32% certified organic Alcohol

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.
General Statements

Super concentrated 1,000 mg

Since 1972

Our facility is cGMP certified, organic and kosher certified.

General

9297E Rev. 515 1150A

Seals/Symbols

Bio-Chelated Cold Extraction Process

Gluten Free

K Parve

Brand IP Statement(s)

Advanced Botanical Fingerprint

Discover Nature's Answer

Our organic alcohol extracts are produced using our cold Bio-Chelated proprietary extraction process, yielding a Holistically Balanced Advanced Botanical Fingerprint extract in the same synergistic ratios as in the plant.

2015 Nature's Answer

Formula

Uncaria tomentosa

K Parve

FDA Statement of Identity

Herbal Supplement

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement, take 1 mL (28 drops) three (3) times a day in a small amount of water. Shake well.

Precautions

Keep out of reach of children.

Warning: Do not use if pregnant or nursing.

Do not use if safety seal is damaged or missing.

Formulation

Gluten-Free

Organic Alcohol

FDA Disclaimer Statement

These statements have not been evaluated by the FDA. 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 1,000 mg by Nature's Answer label

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

Cat's Claw 1,000 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 Cat's Claw 1,000 mg by Nature's Answer

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

Serving size1 mL Dosage formLiquid Servings per container60 Amounts shown are per serving.

Cat’s Claw (Uncaria tomentosa) inner bark extract

Interacts with
962 drugs
1000 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 (Uncaria tomentosa) inner bark extract monograph & interactions

Other (inactive) ingredients: Purified Water, 24-32% certified organic Alcohol. These complete the product’s ingredient list but are not active constituents.

Interaction report

Cat's Claw 1,000 mg by Nature's Answer Drug Interactions

Want to check YOUR meds against Cat's Claw 1,000 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 (Uncaria tomentosa) inner bark extract 962

Individual Drug Interactions

The ingredients in Cat's Claw 1,000 mg interact with 962 drugs. Click any drug to see the details.

1 of the 1 ingredient in Cat's Claw 1,000 mg interact with drugs. Each result below shows which ingredient is responsible. Cat’s Claw (Uncaria tomentosa) inner bark extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Cat's Claw 1,000 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 Claw (Uncaria tomentosa) inner 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 (Uncaria tomentosa) inner bark extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Cat's Claw 1,000 mg, from the product label.

Nature's Answer

See all Nature's Answer products
Name
Nature's Answer
City
Hauppauge
State
NY
ZipCode
11788-3943
Phone Number
(800) 439-2324
Web Address
www.naturesanswer.com
Pharmacist Counseling Corner

Cat's Claw 1,000 mg by Nature's Answer: Common Questions

Does Cat's Claw 1,000 mg by Nature's Answer interact with any medications?
Yes. Based on its ingredients, Cat's Claw 1,000 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?
Cat's Claw 1,000 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.
Can I take cat's claw if I'm pregnant or breastfeeding?
No. The safety data advises against cat's claw in pregnancy because of its traditional use as an abortifacient and lack of safety research. You should also avoid it while breastfeeding due to insufficient information. Talk with your obstetrician or pharmacist if you're considering it.
What side effects might I notice?
In one trial, headache, fatigue, and insomnia each occurred in a small number of participants, and neuropathy (nerve pain) in 8%. Blood-related effects like low red cells, white cells, or platelets were also reported, though those patients had advanced cancer. Long-term safety data is limited, so we don't know all the risks.
Is cat's claw proven to work for allergies, asthma, or other conditions on the label?
Not yet. We don't have enough reliable evidence to confirm cat's claw works for allergic rhinitis, asthma, Alzheimer disease, osteoporosis, cancer, or chronic fatigue syndrome. That means research is either limited or mixed, not that it doesn't help — just that we can't say for sure.
Why does this supplement interact with so many medications?
Cat's claw affects how your body processes certain drugs and may lower blood pressure and affect immune function. It contains alkaloids that interact with liver enzymes (CYP3A4), blood clotting, and blood vessel function — all systems that many medications rely on. That's why the interaction count is high.
Is it safe to take long-term?
Short-term safety in healthy adults looks reasonable, but long-term safety hasn't been well studied. If you're thinking of using it regularly, talk with your pharmacist first, especially if you have kidney or blood pressure concerns.

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 1,000 mg label
Go deeper

The Full Monographs Behind Cat's Claw 1,000 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

Cat's Claw 1,000 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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