Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Resveragen Ingredients & Drug Interactions

by Klaire Labs

Resveragen 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 Resveragen 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

Resveragen is a dietary supplement by Klaire Labs with 1 active ingredient. Its ingredients are commonly taken for source of resveratrol, heart and circulation support, inflammation.Based on those ingredients, 826 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Japanese Knotweed Root Extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Resveragen by Klaire Labs

Ask about any prescription or over-the-counter medication and we check it for interactions with Resveragen by Klaire Labs — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of Resveragen by Klaire Labs

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.

Resveragen contains one active ingredient: Japanese Knotweed Root Extract, a plant-derived ingredient from traditional medicine. The product also includes inactive ingredients — a capsule made from cellulose, plus microcrystalline cellulose, water, ascorbyl palmitate, and silicon dioxide — that help form 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 Hu Zhang product and its label doesn't state a use — see Hu Zhang'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 Japanese Knotweed Root Extract isn't established in our data. We hold insufficient reliable evidence to rate it for hepatitis, rheumatoid arthritis, wound healing, gout, osteoarthritis, or unstable angina.

That doesn't mean it doesn't work — it means the studies we have aren't robust enough yet to draw firm conclusions.

The evidence, ingredient by ingredient Hu Zhang

How safe is it?

Some data gaps
Safety Information · database check
Some gaps

Safety data exists for these ingredients, but with some important gaps.

Why this rating?
  • We hold adverse-effect (side-effect) data for 0 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.

Safety data on this extract in humans is limited. The ingredient's emodin content may cause digestive upset in some people.

The safety data advises against use during pregnancy because some compounds in the extract may affect the uterus. There isn't enough safety information to use it while breastfeeding, so it's best avoided during that time.

Side effects, ingredient by ingredient Hu Zhang

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 — Hu Zhang.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 827 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 product if you take blood thinners or antiplatelet drugs (Moderate risk). Also verify any medications metabolized by your liver's CYP1A2, CYP2C19, CYP3A4, or CYP2E1 enzymes, estrogen replacement therapy, or carbamazepine (Tegretol).

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 some safety-information gaps remain.

If you're taking blood thinners, older seizure medications, or drugs processed through your liver's CYP enzymes, talk to your pharmacist before starting Resveragen. The evidence for its effectiveness isn't clear yet, and pregnancy and breastfeeding are times to skip it.

A quick medication check on this page is your first step.

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 16, 2022.

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 Resveragen, straight from the product label.

Brand Klaire Labs
Barcode (UPC) 828054001565
Net contents 60 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Jun 16, 2022
DSLD ID 264961
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years), Gluten Free, Dairy 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 Resveragen by Klaire Labs, 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
60
UPC/BARCODE
828054001565
IngredientAmount% DV
Japanese Knotweed Root Extract500 mg--

Other ingredients: Hydroxypropyl Methylcellulose, Water, Microcrystalline Cellulose, Ascorbyl Palmitate, Silicon Dioxide

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.
FDA Statement of Identity

Herbal Supplement

Precautions

Caution: If you are pregnant, nursing, have a medical condition, or taking prescription drugs, consult your physician before using this product.

Keep out of reach of children.

Do not use if shrinkwrap is broken or missing.

Formulation

Free of the following common allergens: Milk/casein, eggs, fish, shellfish, tree nuts, peanuts, wheat, gluten, soybeans, corn, and yeast. Contains no artificial colors, flavors, or preservatives.

Produced under a strict quality management system in compliance with Good Manufacturing Practices (GMPs) and third-party quality certifications.

Suggested/Recommended/Usage/Directions

Suggested Use: 1 capsule, 1 to 2 times daily with food or as directed by a healthcare professional.

Formula

This botanical extract supplies a concentrated amount of resveratrol in its biologically active trans form. Each 500 mg capsule supplies 250 mg of trans-resveratrol.

Storage

Store in a cool, dry place (59 degrees F - 85 degrees F) away from direct light.

Brand IP Statement(s)

SFI

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

See for yourself

Resveragen by Klaire Labs label

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

Resveragen 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 Resveragen by Klaire Labs

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 container60 Amounts shown are per serving.

Japanese Knotweed Root Extract

Interacts with
826 drugs
500 mg per serving Form: Trans-Resveratrol

Hu Zhang (Japanese knotweed root) is a traditional Chinese herb that is one of the richest natural sources of resveratrol and emodin. Some lab and ear...

Japanese Knotweed Root Extract monograph & interactions

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

Interaction report

Resveragen by Klaire Labs Drug Interactions

Want to check YOUR meds against Resveragen?

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
826Drugs
826 Moderate

Ingredients driving the most interactions

Japanese Knotweed Root Extract 826

Individual Drug Interactions

The ingredients in Resveragen interact with 826 drugs. Click any drug to see the details.

1 of the 1 ingredient in Resveragen interact with drugs. Each result below shows which ingredient is responsible. Japanese Knotweed Root Extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Resveragen 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.

Japanese Knotweed Root Extract7 drug types · 826 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, hu zhang might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.
Hu zhang contains the constituent resveratrol. Resveratrol seems to have antiplatelet effects.

Likelihood Possible Evidence D
Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, hu zhang might increase levels of drugs metabolized by CYP1A2.
Hu zhang contains the constituent resveratrol. In vitro research shows that resveratrol might inhibit the CYP1A2 enzyme. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2C19 (Cyp2C19) Substrates

Theoretically, hu zhang might increase levels of drugs metabolized by CYP2C19.
Hu zhang contains the constituent resveratrol. In vitro research shows that resveratrol might inhibit the CYP2C19 enzyme. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2E1 (Cyp2E1) Substrates

Theoretically, hu zhang might increase levels of drugs metabolized by CYP2E1.
Hu zhang contains the constituent resveratrol. In vitro research shows that resveratrol might inhibit the CYP2E1 enzyme. Also, a pharmacokinetic study shows that taking resveratrol 500 mg daily for 10 days prior to taking a single dose of chlorzoxazone 250 mg increases the maximum concentration of chlorzoxazone by about 54%, the area under the curve of chlorzoxazone by about 72%, and the half-life of chlorzoxazone by about 35%. Chlorzoxazone is used as a probe drug for CYP2E1.

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

Theoretically, hu zhang might increase levels of drugs metabolized by CYP3A4.
Hu zhang contains the constituent resveratrol. In vitro research shows that resveratrol might inhibit the CYP3A4 enzyme. However, a clinical study in adults with NAFLD found that adding resveratrol 3000 mg daily for 8 weeks did not necessitate dose adjustments to any established medications metabolized by CYP3A4.

Likelihood Possible Evidence D
Estrogens

Theoretically, hu zhang might competitively inhibit the effects of estrogen replacement therapy.
In vitro research shows that hu zhang might have estrogenic activity.

Likelihood Possible Evidence D
Carbamazepine (Tegretol)

Theoretically, hu zhang might increase the effects and adverse effects of carbamazepine.
In animals, blood and tissue levels of carbamazepine were increased when given in combination with hu zhang. It is thought that increased levels of carbamazepine are due to cytochrome P450 3A4 (CYP3A4) inhibition. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Japanese Knotweed Root Extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Resveragen, from the product label.

Klaire Labs

See all Klaire Labs products
Name
SFI USA
City
Reno
State
NV
ZipCode
89521
Web Address
Klaire.com
Pharmacist Counseling Corner

Resveragen by Klaire Labs: Common Questions

Does Resveragen by Klaire Labs interact with any medications?
Yes. Based on its ingredients, Resveragen has a known interaction with 826 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Resveragen 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.
Will this help my arthritis or gout?
The evidence for Japanese Knotweed Root Extract isn't clear enough to rate yet for either condition. You may want to talk with your doctor about whether it's worth trying while we wait for stronger studies.
Can I take this while pregnant?
The safety data advises against it. Some compounds in the extract may affect the uterus, and there isn't enough information to know it's safe during pregnancy. Talk with your doctor or pharmacist before using it.
Is it safe to breastfeed while taking Resveragen?
No, there isn't enough safety information, so it's best avoided while breastfeeding. Speak with your pharmacist or doctor if you have questions about timing.
What's the emodin I hear about in this plant?
Emodin is a compound naturally found in Japanese Knotweed. It's one reason the extract may cause digestive upset in some people — something to watch for when you start.
Does this extract have other side effects listed?
We don't have specific trial data on side effects for this product. The main caution is digestive upset from the emodin content. If you notice anything unusual, let your pharmacist know.

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

Not sure if Resveragen is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.

Resveragen label
Go deeper

The Full Monographs Behind Resveragen’s Ingredients

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

Herb & supplement monograph

Hu Zhang

Interacts with 826 drugs

Hu Zhang (Japanese knotweed root) is a traditional Chinese herb that is one of the richest natural sources of resveratrol and emodin. Some lab and early human research looks interesting for...

Read the full Hu Zhang monograph →
Sources

Sources & How We Checked

Resveragen'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 19 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.

Hu Zhang 19 references
  1. Pace-Asciak CR, Rounova O, Hahn SE, et al. Wines and grape juices as modulators of platelet aggregation in healthy human subjects. Clin Chim Acta 1996;246:163-82. PubMed
  2. Bertelli AA, Giovannini L, Bernini W, et al. Antiplatelet activity of cis-resveratrol. Drugs Exp Clin Res 1996;22:61-3.
  3. Pace-Asciak CR, Hahn S, Diamandis EP, et al. The red wine phenolics trans-resveratrol and quercetin block human platelet aggregation and eicosanoid synthesis: implications for protection against coronary heart disease. Clin Chim Acta 1995;235:207-19.
  4. Bertelli A, Bertelli AA, Gozzini A, Giovannini L. Plasma and tissue resveratrol concentrations and pharmacological activity. Drugs Exp Clin Res 1998;24:133-8.
  5. Bertelli AA, Giovannini L, Giannessi D, et al. Antiplatelet activity of synthetic and natural resveratrol in red wine. Int J Tissue React 1995;17:1-3.
  6. Piver B, Berthou F, Dreano Y, Lucas D. Inhibition of CYP3A, CYP1A and CYP2E1 activities by resveratrol and other non volatile red wine components. Toxicol Lett 2001;125:83-91. PubMed
  7. Matsuda H, Shimoda H, Morikawa T, Yoshikawa M. Phytoestrogens from the roots of Polygonum cuspidatum (Polygonaceae): structure-requirement of hydroxyanthraquinones for estrogenic activity. Bioorg Med Chem Lett 2001;11:1839-42. PubMed
  8. Zhang CZ, Wang SX, Zhang Y, et al. In vitro estrogenic activities of Chinese medicinal plants traditionally used for the management of menopausal symptoms. J Ethnopharmacol 2005;98:295-300. PubMed
  9. Chang, T. K., Chen, J., and Lee, W. B. Differential inhibition and inactivation of human CYP1 enzymes by trans-resveratrol: evidence for mechanism-based inactivation of CYP1A2. J.Pharmacol.Exp.Ther. 2001;299(3):874-882.
  10. Dobrydneva, Y., Williams, R. L., and Blackmore, P. F. trans-Resveratrol inhibits calcium influx in thrombin-stimulated human platelets. Br.J.Pharmacol. 1999;128(1):149-157.
  11. Kirk, R. I., Deitch, J. A., Wu, J. M., and Lerea, K. M. Resveratrol decreases early signaling events in washed platelets but has little effect on platalet in whole food. Blood Cells Mol.Dis. 2000;26(2):144-150.
  12. Zbikowska, H. M. and Olas, B. Antioxidants with carcinostatic activity (resveratrol, vitamin E and selenium) in modulation of blood platelet adhesion. J Physiol Pharmacol. 2000;51(3):513-520.
  13. Olas, B., Wachowicz, B., Saluk-Juszczak, J., and Zielinski, T. Effect of resveratrol, a natural polyphenolic compound, on platelet activation induced by endotoxin or thrombin. Thromb.Res 8-15-2002;107(3-4):141-145. PubMed
  14. Yu, C., Shin, Y. G., Kosmeder, J. W., Pezzuto, J. M., and van Breemen, R. B. Liquid chromatography/tandem mass spectrometric determination of inhibition of human cytochrome P450 isozymes by resveratrol and resveratrol-3-sulfate. Rapid Commun.Mass Spectro PubMed
  15. Ma, Z. H. and Ma, Q. Y. Resveratrol: a medical drug for acute pancreatitis. World J Gastroenterol. 6-7-2005;11(21):3171-3174. PubMed
  16. Pendurthi, U. R., Williams, J. T., and Rao, L. V. Resveratrol, a polyphenolic compound found in wine, inhibits tissue factor expression in vascular cells : A possible mechanism for the cardiovascular benefits associated with moderate consumption of wine. PubMed
  17. Chachay VS, Macdonald GA, Martin JH, Whitehead JP, O'Moore-Sullivan TM, Lee P, Franklin M, Klein K, Taylor PJ, Ferguson M, Coombes JS, Thomas GP, Cowin GJ, Kirkpatrick CM, Prins JB, Hickman IJ. Resveratrol does not benefit patients with nonalcoholic fatty
  18. Bedada SK, Neerati P. Resveratrol Pretreatment Affects CYP2E1 Activity of Chlorzoxazone in Healthy Human Volunteers. Phytother Res. 2016;30(3):463-8. PubMed
  19. Chi YC, Lin SP, Hou YC. A new herb-drug interaction of Polygonum cuspidatum, a resveratrol-rich nutraceutical, with carbamazepine in rats. Toxicol Appl Pharmacol 2012;263(3):315-22. PubMed

See these in context on the Hu Zhang 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

Keep exploring
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team