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Dietary supplement

Avmacol Extra Strength Ingredients & Drug Interactions

by Nutramax Laboratories Consumer Care

Avmacol Extra Strength label
See full label image
Tablet Or Pill Category: Other Combinations
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 Avmacol Extra Strength 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

Avmacol Extra Strength is a dietary supplement by Nutramax Laboratories Consumer Care with 4 active ingredients. Its ingredients are commonly taken for common cold and immune support, antioxidant support, skin health and collagen formation.Based on those ingredients, 603 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Maitake Mushroom extract, Vitamin C, Broccoli seed & sprout 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 Avmacol Extra Strength by Nutramax Laboratories Consumer Care

Ask about any prescription or over-the-counter medication and we check it for interactions with Avmacol Extra Strength by Nutramax Laboratories Consumer Care — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Avmacol Extra Strength by Nutramax Laboratories Consumer Care

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 16, 2026

What’s inside

Partial disclosure
Ingredient Transparency · database check
Partial

Most active ingredients list an amount, but at least one is hidden in a blend or missing.

Why this rating?
  • The label discloses an exact amount for 2 of its 4 active ingredients.
  • “Proprietary Sulforaphane Glucosinolate (Glucoraphanin) & Myrosinase Blend” is a proprietary blend — the label gives one combined amount (490 mg) without saying how much of each component you get.
  • “Broccoli seed & sprout extract” is listed as a grouped ingredient — the label doesn't break down how much of each component you get.

Avmacol Extra Strength contains 4 active ingredients. Vitamin C is a well-known antioxidant and immune supporter.

Glucoraphanin and a proprietary blend of myrosinase are plant compounds from broccoli seed and sprout extract thought to support cellular health. Maitake mushroom extract is a fungal polysaccharide used in traditional wellness approaches.

Wasabi rounds out the formula with pungent plant compounds. The tablet also contains several inactive ingredients — microcrystalline cellulose, maltodextrin, hydroxypropyl cellulose, and starch — that serve as binders and fillers.

Does it work?

Strong evidence
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

This product doesn't appear to be marketed for a specific use, so we graded its ingredients' overall clinical evidence instead.

Strong

Strong clinical evidence supports its ingredients for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredients' overall clinical evidence instead.
  • On file: Vitamin C deficiency — rated "Effective" (Vitamin C) (Natural Medicines).
  • On file: Hypercholesterolemia — rated "Possibly Effective" (Vitamin C) (Natural Medicines).
  • On file: Anemia of chronic disease — rated "Possibly Effective" (Vitamin C) (Natural Medicines).
  • On file: Atrial fibrillation — rated "Possibly Effective" (Vitamin C) (Natural Medicines).
  • On file: Laser skin resurfacing — rated "Possibly Effective" (Vitamin C) (Natural Medicines).

Evidence for this product's active ingredients is mixed. Vitamin C is effective for preventing vitamin C deficiency and is possibly effective for anemia of chronic disease, atrial fibrillation, cataracts, and exercise-induced respiratory infections.

For the other three active ingredients — glucoraphanin, maitake mushroom, and wasabi — the evidence in our data is insufficient to rate their effectiveness for the conditions studied. That doesn't mean they don't work; it means large, well-controlled trials are lacking.

The evidence, ingredient by ingredient Vitamin C Maitake Mushroom Broccoli Wasabi

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 3 of the 3 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 3 of 3.
  • General safety write-ups exist for 3 of 3.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin C is generally well tolerated at normal doses, though very high doses can cause abdominal cramps, heartburn, diarrhea, nausea, and kidney stones in people prone to them — adverse effects become more likely above 2 grams daily. Maitake mushroom is generally well tolerated as a food, but concentrated supplement safety hasn't been fully studied; a small number of trial participants reported diarrhea, gastrointestinal upset, or mild allergic reactions.

Wasabi is generally safe as a food, but concentrated supplement doses haven't been well studied in people. For pregnancy and breastfeeding, vitamin C at normal amounts is fine, but avoid high-dose supplements unless your doctor advises it.

Maitake mushroom and wasabi concentrated supplements should be avoided during pregnancy and breastfeeding due to lack of safety data.

Side effects, ingredient by ingredient Vitamin C Maitake Mushroom Broccoli Wasabi

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?
  • 3 of the 3 matched ingredients can interact with medications — Maitake Mushroom, Vitamin C, Wasabi.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; cancer treatments; diabetes medications.
  • For scale: 542 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 taking Avmacol Extra Strength, check with your doctor or pharmacist if you take any blood thinners or antiplatelet drugs (warfarin or others), estrogen-based medications (birth control or hormone replacement), chemotherapy drugs, antihypertensive drugs (blood pressure medications), diabetes medications, the antipsychotic fluphenazine, the HIV medication indinavir, thyroid medication levothyroxine, or aluminum-containing supplements.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glancePartially disclosed formula with strong clinical evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

Avmacol Extra Strength may appeal to someone looking for antioxidant and plant-based support, particularly for vitamin C deficiency or as a general wellness aid. However, if you take warfarin, estrogen-based birth control or hormone therapy, diabetes medications, blood pressure medications, chemotherapy, or any other prescription drugs, you'll want to check your specific medications with your doctor or pharmacist before starting this product.

The interaction potential is real, and some could affect how your drugs work.

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

Assessment coverage: 3 of 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jul 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 Avmacol Extra Strength, straight from the product label.

Brand Nutramax Laboratories Consumer Care
Barcode (UPC) 755970150148
Net contents 30 Tablet(s)
Market status On market
Date entered into DSLD Jul 23, 2020
DSLD ID 228840
Product type Other Combinations
Supplement form Tablet Or Pill
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
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 Avmacol Extra Strength by Nutramax Laboratories Consumer Care, 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 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
Servings per container
30
UPC/BARCODE
755970150148
IngredientAmount% DV
Total Carbohydrates1 Gram(s)1%
Vitamin C25 mg28%
Glucoraphanin30 mg--
Maitake Mushroom extract0 NP--
Proprietary Sulforaphane Glucosinolate (Glucoraphanin) & Myrosinase Blend490 mg--
Broccoli seed & sprout extract0 NP--
Wasabi0 NP--

Other ingredients: Microcrystalline Cellulose, Maltodextrin, Hydroxypropyl Cellulose, Starch, Contains <2% of

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.
Formula

Unleash the power of Broccoli Sulforaphane Production System with Myrosimax active Myrosinase

FDA Statement of Identity

Dietary Supplement

Brand IP Statement(s)

U.S. Patent No. 9,421,183

Suggested/Recommended/Usage/Directions

Directions for use: Take 1 tablet per day with a meal.

Precautions

If you have any condition that requires medical attention always consult your physician before taking any dietary supplement.

Important: Tamper evident seal under cap. Do not use if seal is broken or missing.

Storage

Keep in a cool, dry place.

General Statements

Learn more: AVMACOL.COM or 1-855-AVMACOL (1-855-286-2265)

I Samuel 12:24

FDA Disclaimer Statement

These statements have 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

Avmacol Extra Strength by Nutramax Laboratories Consumer Care label

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

Avmacol Extra Strength 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 Avmacol Extra Strength by Nutramax Laboratories Consumer Care

These are the 4 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Tablet(s) Dosage formTablet Or Pill Servings per container30 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.

Vitamin C

Interacts with
207 drugs
25 mg per serving Form: Ascorbic Acid

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for im...

Vitamin C monograph & interactions

Proprietary Sulforaphane Glucosinolate (Glucoraphanin) & Myrosinase Blend

490 mg per serving

Other (inactive) ingredients: Microcrystalline Cellulose, Maltodextrin, Hydroxypropyl Cellulose, Starch, Contains <2% of. These complete the product’s ingredient list but are not active constituents.

Interaction report

Avmacol Extra Strength by Nutramax Laboratories Consumer Care Drug Interactions

Want to check YOUR meds against Avmacol Extra Strength?

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
603Drugs
595 Moderate 8 Minor

Ingredients driving the most interactions

Maitake Mushroom extract 260
Vitamin C 207
Broccoli seed & sprout extract 187
Wasabi 122

Individual Drug Interactions

The ingredients in Avmacol Extra Strength interact with 603 drugs. Click any drug to see the details.

4 of the 4 ingredients in Avmacol Extra Strength interact with drugs. Each result below shows which ingredient is responsible. Maitake Mushroom extract Vitamin C Broccoli seed & sprout extract Wasabi

Each ingredient & the kinds of drugs it affects

For each ingredient in Avmacol Extra Strength with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Maitake Mushroom extract3 drug types · 260 drugs

Antidiabetes Drugs

Theoretically, combining maitake mushroom with antidiabetes drugs might increase the risk of hypoglycemia.
Clinical research shows that taking maitake mushroom polysaccharide (MMP) can lower blood glucose levels in patients with types 2 diabetes.

Likelihood Possible Evidence B
Antihypertensive Drugs

Theoretically, combining maitake mushroom with antihypertensive drugs might increase the risk of hypotension.
Animal research shows that maitake mushroom can lower blood pressure.

Likelihood Possible Evidence D
Warfarin (Coumadin)

There is limited evidence that maitake mushroom may increase the anticoagulant effects of warfarin.
In a case report, a patient previously stabilized on warfarin developed an elevated international normalized ratio (INR) of 5.1 after taking maitake mushroom (Grifron-Pro Maitake D-Fraction) 1 drop/kg daily in three divided doses for one week. The elevated INR resolved after holding warfarin for two days, then reducing the dose by 11%. It is thought that the beta-glucan constituent of maitake mushroom might cause warfarin dissociation from proteins, resulting in increased free warfarin levels and increased warfarin effects.

Likelihood Possible Evidence D
Maitake Mushroom extract full monograph & interactions

Vitamin C13 drug types · 207 drugs

Alkylating Agents

Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Aluminum

Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption. In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely. Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.

Likelihood Probable Evidence B
Antitumor Antibiotics

Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Estrogens

Vitamin C might increase blood levels of estrogens.
Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products. It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall. When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements. Monitor these patients for estrogen-related side effects.

Likelihood Probable Evidence B
Fluphenazine (Prolixin)

Theoretically, vitamin C might decrease levels of fluphenazine.
In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started. The mechanism is not known, and there is no further data to confirm this interaction.

Likelihood Possible Evidence D
Indinavir (Crixivan)

Vitamin C can modestly reduce indinavir levels.
One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown.

Likelihood Probable Evidence B
Levothyroxine (Synthroid, Others)

Vitamin C can increase levothyroxine absorption.
Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH.

Likelihood Probable Evidence B
Warfarin (Coumadin)

High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption. There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time. Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant. However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.

Likelihood Possible Evidence D
Acetaminophen (Tylenol, Others)

High-dose vitamin C might slightly prolong the clearance of acetaminophen.
A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases. This effect is not likely to be clinically significant.

Likelihood Probable Evidence B
Aspirin

Acidification of the urine by vitamin C might increase aspirin levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction is not clinically significant.

Likelihood Possible Evidence B
Choline Magnesium Trisalicylate (Trilisate)

Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Niacin

Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.
A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease. It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.

Likelihood Possible Evidence A
Salsalate (Disalcid)

Acidification of the urine by vitamin C might increase salsalate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Vitamin C full monograph & interactions

Broccoli seed & sprout extract2 drug types · 187 drugs

Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, broccoli might reduce the levels and effects of drugs metabolized by CYP1A2.
Pharmacokinetic research in humans shows that eating 500 grams of fresh broccoli daily for 6-12 days can increase CYP1A2 activity by 10% to 200%. Induction of CYP1A2 activity by broccoli is attributed to its glucosinolate constituents.

Likelihood Possible Evidence B
Cytochrome P450 2A6 (Cyp2A6) Substrates

Theoretically, broccoli might reduce the levels and effects of drugs metabolized by CYP2A6.
Pharmacokinetic research in humans shows that eating 500 grams of broccoli daily for 6 days increases CYP2A6 activity by 135% to 550%. Induction of CYP2A6 activity is attributed to its glucosinolate constituents.

Likelihood Possible Evidence B
Broccoli seed & sprout extract full monograph & interactions

Wasabi1 drug type · 122 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, wasabi might increase the risk of bleeding with anticoagulant or antiplatelet drugs.
In vitro research shows that 6-(methylsulfinyl) hexyl isothiocyanate, a constituent of wasabi, inhibits platelet aggregation.

Likelihood Possible Evidence D
Wasabi full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Avmacol Extra Strength, from the product label.

Nutramax Laboratories Consumer Care

See all Nutramax Laboratories Consumer Care products
Name
Nutramax Laboratories Consumer Care, Inc.
City
Edgewood
State
Maryland
ZipCode
21040
Phone Number
1-800-925-5187
Web Address
nutramaxlabs.com
Pharmacist Counseling Corner

Avmacol Extra Strength by Nutramax Laboratories Consumer Care: Common Questions

Does Avmacol Extra Strength by Nutramax Laboratories Consumer Care interact with any medications?
Yes. Based on its ingredients, Avmacol Extra Strength has a known interaction with 603 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Avmacol Extra Strength contains 4 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.
Is vitamin C in this supplement safe at normal doses?
Yes, vitamin C is generally well tolerated at normal dietary and supplement doses. Side effects like diarrhea, heartburn, and nausea are more likely above 2 grams daily, and kidney stones can occur in people prone to them.
Can I take this if I'm pregnant or breastfeeding?
Normal amounts of vitamin C from food and prenatal vitamins are fine, but avoid high-dose supplements unless your doctor advises it. Maitake mushroom and wasabi concentrated supplements should be avoided during pregnancy and breastfeeding due to insufficient safety data — talk with your doctor or pharmacist.
What is glucoraphanin, and does it interact with any medications?
Glucoraphanin is a plant compound from broccoli seed and sprout extract. We don't hold interaction data for it, so we cannot check whether it affects any medications.
Does maitake mushroom in this product lower blood sugar or blood pressure?
Clinical research shows maitake mushroom can lower blood glucose in people with type 2 diabetes and animal research shows it can lower blood pressure. If you take diabetes or blood pressure medications, check with your doctor or pharmacist before adding this product.
What side effects did people experience in studies of these ingredients?
Vitamin C at high doses can cause diarrhea, heartburn, and nausea. In maitake mushroom trials, a small number of participants reported diarrhea, gastrointestinal pain, or mild rash. In wasabi studies, a small number reported protein in urine or mild liver enzyme changes.
Can I take this with warfarin?
Vitamin C at high doses may reduce warfarin's effectiveness, and there's a case report of maitake mushroom increasing warfarin's blood-thinning effect, raising bleeding risk. Do not take this product with warfarin without checking with your doctor or pharmacist first.

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.

Avmacol Extra Strength label
Go deeper

The Full Monographs Behind Avmacol Extra Strength’s Ingredients

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

Herb & supplement monograph

Vitamin C

Interacts with 207 drugs

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for immune function, collagen, and acts as an...

Read the full Vitamin C monograph → Herb & supplement monograph

Maitake Mushroom

Interacts with 260 drugs

Maitake is an edible mushroom long used as food and in traditional Japanese medicine, and it is being studied for possible immune, blood sugar, and blood pressure effects. The human evidence...

Read the full Maitake Mushroom monograph → Herb & supplement monograph

Broccoli

Interacts with 187 drugs

Broccoli is a nutritious cruciferous vegetable rich in fiber, vitamins, and plant compounds like sulforaphane that have drawn scientific interest for health benefits. Eating broccoli as food...

Read the full Broccoli monograph → Herb & supplement monograph

Wasabi

Interacts with 122 drugs

Wasabi is best known as the pungent green condiment served with sushi, made from a Japanese plant in the cabbage family. Its natural compounds (isothiocyanates) show antimicrobial and antiox...

Read the full Wasabi monograph →
Sources

Sources & How We Checked

Avmacol Extra Strength'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 66 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.

Vitamin C 51 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
  3. Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
  4. Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
  5. Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent
  6. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
  7. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  8. Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
  9. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
  10. Houston JB, Levy G. Drug biotransformation interactions in man VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218-21. PubMed
  11. Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93. DOI
  12. Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671. DOI
  13. Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479. DOI
  14. Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166. DOI
  15. Traxer O, Huet B, Poindexter J, et al. Effect of ascorbic acid consumption on urinary stone risk factors. J Urol 2003;170:397-401.. PubMed
  16. Domingo JL, Gomez M, Llobet JM, Richart C. Effect of ascorbic acid on gastrointestinal aluminum absorption (letter). Lancet 1991;338:1467.
  17. Domingo JL, Gomez M, Llobet JM, Corbella J. Influence of some dietary constituents on aluminum absorption and retention in rats. Kidney Int 1991;39:598-601. PubMed
  18. Partridge NA, Regnier FE, White JL, Hem SL. Influence of dietary constituents on intestinal absorption of aluminum. Kidney Int 1989;35:1413-7. PubMed
  19. Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413. DOI
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Maitake Mushroom 8 references
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Broccoli 5 references
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See these in context on the Broccoli monograph →

Wasabi 2 references
  1. Morimitsu, Y., Hayashi, K., Nakagawa, Y., Fujii, H., Horio, F., Uchida, K., and Osawa, T. Antiplatelet and anticancer isothiocyanates in Japanese domestic horseradish, Wasabi. Mech Ageing Dev 2000;116(2-3):125-134. PubMed
  2. Nakajima R, Kanou M, Tokushima M, Iwama Y, Yamana K. Oral administration of 6-methylsulfinylhexyl isothiocyanate extracted from wasabi is safe and improves the fatigue and sleep of healthy volunteers. Biopsychosoc Med 2023;17(1):30. PubMed

See these in context on the Wasabi monograph →

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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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