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Dietary supplement

Cat's Claw Inner Bark Extract Ingredients & Drug Interactions

by Solgar

Cat's Claw Inner Bark Extract 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 Inner Bark Extract 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 Inner Bark Extract is a dietary supplement by Solgar with 2 active ingredients. 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 standardized Cat's Claw 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 Inner Bark Extract by Solgar

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

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HelloPharmacist Scorecard of Cat's Claw Inner Bark Extract by Solgar

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 2 of its 2 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains 2 active ingredients: a standardized Cat's Claw extract and raw Cat's Claw powder. Both come from the inner bark of the cat's claw plant and deliver the same alkaloids (rhynchophylline, isorhynchophylline, corynoxeine, and isocorynoxiene) that give the herb its effects.

The capsule also contains inactive ingredients — microcrystalline cellulose, vegetable cellulose, vegetable magnesium stearate, and a phytosterol antioxidant blend — that help hold the capsule together and preserve freshness.

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 for cat's claw isn't established in our data for any of the conditions it's marketed for — allergic rhinitis (hay fever), Alzheimer disease, asthma, osteoporosis, cancer, and chronic fatigue syndrome all carry an Insufficient Reliable Evidence To Rate rating. That doesn't mean it doesn't work; it means the research we have isn't robust enough to make a confident claim either way.

If you're considering it for a specific health goal, talk with us or your doctor about what the broader research shows and whether a trial makes sense for you.

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 short-term in healthy adults, but long-term safety hasn't been well studied, so we don't have solid data on what happens with months or years of use. In one clinical trial, a small number of participants experienced anemia (12%), blood count drops (2% each), headache (2%), fatigue (4%), insomnia (4%), and nerve damage (8%) — though these patients had advanced cancer with no other treatment options, so it's unclear whether the supplement or their disease caused these effects.

Several case reports have linked cat's claw to kidney injury, including acute kidney failure and inflammation of the kidney tissue, though symptoms improved after stopping the supplement in the cases reported. The safety data advises against use during pregnancy because of its traditional use to trigger miscarriage and lack of safety research.

Don't use it while breastfeeding either — there isn't enough data to know whether 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, check with us if you're on blood pressure medications (antihypertensives or calcium channel blockers like diltiazem or verapamil), blood thinners or antiplatelet drugs (warfarin, aspirin, clopidogrel), Paxlovid, immunosuppressants, or any drug your doctor says is metabolized by the liver enzyme CYP3A4 — that's a big category. These are all Moderate interactions.

Use the medication checker on this page to scan your exact 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 may interest you if you're exploring botanical options for general wellness, but the evidence for specific conditions isn't strong in our data. Be careful if you're on blood pressure drugs, blood thinners, Paxlovid, or medications processed by your liver — this product can interfere with all of them.

Definitely avoid it during pregnancy and breastfeeding, and talk with your pharmacist before starting, especially if you have kidney problems or take any prescription medications.

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

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Apr 23, 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 Cat's Claw Inner Bark Extract, straight from the product label.

Brand Solgar
Barcode (UPC) 033984041134
Net contents 60 Vegetable Capsule(s)
Market status On market
Date entered into DSLD Apr 23, 2020
DSLD ID 219019
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other
Intended target group(s) Vegetarian, Adult (18 - 50 Years), Kosher, Gluten Free, Dairy Free, Sugar 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 Inner Bark Extract by Solgar, 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 Vegetarian Capsule(s)
Maximum serving Sizes:
1 Vegetarian Capsule(s)
UPC/BARCODE
033984041134
IngredientAmount% DV
standardized Cat's Claw extract150 mg--
raw Cat's Claw powder300 mg--

Other ingredients: Microcrystalline Cellulose, Vegetable Cellulose, Vegetable Magnesium Stearate, PhytO2X Antioxidant Blend

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.
Formulation

Solgar's Standardized Full Potency (SFP) Herbs are developed through a unique process that integrates the ideologies of both traditional herbalism and standardized herbal technology.

To ensure consistent and reliable phytonutrient levels, we isolate a controlled amount of these important active plant compounds. Then, we blend these enhanced, “standardized” compounds with all of the compounds that occur naturally in the whole raw herb. The result is a potent, premium-quality standardized herbal extract with all of the synergistic and beneficial qualities found in nature.

Standardized Full potency

Gluten, wheat & dairy free

Suitable for vegetarians

Free of: Gluten, wheat, dairy, soy, yeast, sugar, sodium, artificial flavor, sweetener, preservatives and color.

Brand IP Statement(s)

2012 Solgar, Inc.

PHYTO2X(R) SYSTEM

PhytO2X(R) is a special blend of antioxidants, the purpose of which is to maintain the freshness of the ingredients.

General Statements

Solgar since 1947

Formula

(Uncaria tomentosa)

Solgar’s KOF-K certification #K-1250

FDA Statement of Identity

Herbal Supplement

Seals/Symbols

K Parve (Kosher)

Suggested/Recommended/Usage/Directions

Suggested Use: As an herbal supplement for adults, take one (1) vegetable capsule up to three times daily, preferably with meals, or as directed by a healthcare practitioner.

Precautions

If you are pregnant, nursing, taking any medication or have a medical condition, please consult your healthcare practitioner before taking any dietary supplement.

Discontinue use and consult your healthcare practitioner if any adverse reactions occur.

Not intended for use by persons under the age of 18. Keep out of reach of children.

Do not use if outer bottle seal is missing, torn or damaged in any way.

Storage

Store at room temperature.

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

See for yourself

Cat's Claw Inner Bark Extract by Solgar label

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

Cat's Claw Inner Bark Extract 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 Inner Bark Extract by Solgar

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

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

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Standardized Cat's Claw extract

Interacts with
962 drugs
150 mg per serving Form: Alkaloids, Polyphenols

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...

Standardized Cat's Claw extract monograph & interactions

Raw Cat's Claw powder

Interacts with
962 drugs
300 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...

Raw Cat's Claw powder monograph & interactions

Other (inactive) ingredients: Microcrystalline Cellulose, Vegetable Cellulose, Vegetable Magnesium Stearate, PhytO2X Antioxidant Blend. These complete the product’s ingredient list but are not active constituents.

Interaction report

Cat's Claw Inner Bark Extract by Solgar Drug Interactions

Want to check YOUR meds against Cat's Claw Inner Bark Extract?

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

standardized Cat's Claw extract 962

Individual Drug Interactions

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

1 of the 2 ingredients in Cat's Claw Inner Bark Extract interact with drugs. Each result below shows which ingredient is responsible. standardized Cat's Claw extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Cat's Claw Inner Bark Extract 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.

standardized Cat's Claw 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
standardized Cat's Claw extract full monograph & interactions
The maker

Brand information

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

Solgar

See all Solgar products
Name
Solgar, Inc.
Street Address
500 Willow Tree Road
City
Leonia
State
NJ
ZipCode
07605
Phone Number
1-877-765-4274
Web Address
www.solgar.com
Pharmacist Counseling Corner

Cat's Claw Inner Bark Extract by Solgar: Common Questions

Does Cat's Claw Inner Bark Extract by Solgar interact with any medications?
Yes. Based on its ingredients, Cat's Claw Inner Bark Extract 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 Inner Bark Extract contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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 it during pregnancy because of cat's claw's traditional use to cause miscarriage and lack of safety research. Don't use it while breastfeeding either — there isn't enough data to know it's safe for your baby. Talk to your doctor about alternatives if you're interested in supplements during these times.
What side effects might I experience?
One clinical trial reported anemia, low white blood cells, low platelets, headache, fatigue, insomnia, and nerve damage in small numbers of participants, though those patients had advanced cancer and it's unclear whether cat's claw caused these or their disease did. Several case reports link cat's claw to kidney injury. Most healthy people taking it short-term appear to tolerate it okay, but long-term safety data is limited.
Does cat's claw actually work for the conditions it's sold for?
We don't have solid evidence yet. The claims — for hay fever, Alzheimer disease, asthma, osteoporosis, cancer, and chronic fatigue — all have insufficient reliable evidence to rate. That means the research isn't strong enough to confidently say it works for these. Your pharmacist or doctor can talk you through what larger studies suggest.
What's the difference between the standardized extract and the raw powder in this product?
The standardized extract is processed to contain a consistent amount of the active alkaloids; the raw powder is the whole dried herb. Both deliver the same compounds and carry the same interactions and effects based on our data.
Is this product just cat's claw, or does it have fillers?
It contains the two active ingredients plus inactive ones: microcrystalline cellulose, vegetable cellulose, vegetable magnesium stearate, and a phytosterol antioxidant blend. These help the capsule hold together and keep it fresh. If you need a pure product with minimal extras, check the label details or ask us.
How long is it safe to take cat's claw?
Short-term use in healthy adults is generally well tolerated, but long-term safety hasn't been well studied. We don't have good data on what happens if you take it for months or years. If you're thinking about long-term use, check in with your pharmacist or doctor.

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 Inner Bark Extract label
Go deeper

The Full Monographs Behind Cat's Claw Inner Bark Extract’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 Inner Bark Extract'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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