Sustained Release C-500 (Ascorbic Acid) Ingredients & Drug Interactions
What is this page for?
First and foremost: checking Sustained Release C-500 (Ascorbic Acid) 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
Sustained Release C-500 (Ascorbic Acid) is a dietary supplement by Windmill Natural Vitamins with 1 active ingredient. Its ingredients are commonly taken for common cold and immune support, antioxidant support, skin health and collagen formation.Based on those ingredients, 207 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Vitamin C. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins
Ask about any prescription or over-the-counter medication and we check it for interactions with Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins — and tell you which ingredient is responsible.
AI summaries are generated from our interaction database for education only — always confirm with your pharmacist. How we use AI
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HelloPharmacist Scorecard of Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins
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.
What’s inside
Full disclosure
This product contains one active ingredient: vitamin C (ascorbic acid) in a sustained-release form, which means it releases slowly over time in your body. The tablet also includes inactive ingredients—microcrystalline cellulose, hydroxypropyl methyl cellulose, stearic acid, silicon dioxide, magnesium stearate, vegetable coating, and polyethylene glycol—which are fillers and binders that hold the tablet together and help it dissolve properly.
Does it work?
Moderate evidence
Vitamin C is effective for preventing and treating vitamin C deficiency. The evidence is possibly effective for anemia of chronic disease, atrial fibrillation, cataracts, and exercise-induced respiratory infections, though the data here is less conclusive.
If you're taking this for one of those other conditions, talk with us about what the research actually shows and whether it's the right fit for you.
How safe is it?
Well-documented data
Vitamin C is generally well tolerated at normal dietary doses and supplement amounts, but very high doses can cause problems. At doses above 2 grams daily, you may experience abdominal cramps, heartburn, nausea, diarrhea, or headache.
People prone to kidney stones should be cautious, since vitamin C increases kidney stone risk at high doses. In pregnancy and lactation, normal amounts from food and prenatal vitamins are fine, but high-dose supplements should only be used under a doctor's guidance.
Meds to double-check
Moderate interaction found
Before taking this product, double-check if you use estrogens (birth control pills or hormone replacement therapy), warfarin or other blood thinners, levothyroxine (thyroid medication), alkylating agent or antitumor antibiotic chemotherapy drugs, aluminum-containing compounds, the antipsychotic fluphenazine, or the HIV drug indinavir. All have Moderate interactions documented with vitamin C.
The bottom line
Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.
Windmill's C-500 is straightforward—one ingredient, vitamin C—but it does interact with birth control, hormone therapy, blood thinners, thyroid medication, and certain chemotherapy drugs. If you take any prescription medications, especially estrogens or warfarin, check them against this product before you start.
Talk to your pharmacist about your specific situation.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Jul 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
General information
Key facts about Sustained Release C-500 (Ascorbic Acid), straight from the product label.
| Brand | Windmill Natural Vitamins |
|---|---|
| Barcode (UPC) | 035046001971 |
| Net contents | 60 Tablet(s) |
| Market status | On market |
| Date entered into DSLD | Jul 23, 2020 |
| DSLD ID | 231406 |
| Product type | Vitamin |
| Supplement form | Tablet Or Pill |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), Gluten Free, Dairy Free |
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 Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Vitamin C | 500 mg | 556% |
Other ingredients: Microcrystalline Cellulose, Hydroxypropyl Methyl Cellulose, Stearic Acid, Silicon Dioxide, Magnesium Stearate, Vegetable Coating, Polyethylene Glycol
Tap any ingredient to jump to its full detail below.
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.
Suggested/Recommended/Usage/Directions
Directions: Take 1 tablet daily as a dietary supplement or as directed by a healthcare professional.
Precautions
Keep out of reach of children.
Do not purchase if seal is broken.
Storage
Protect from heat, light & moisture. Store in a cool, dry place.
Formulation
Made in the U.S.A. from globally sourced ingredients.
Immune system support Antioxidant support
No yeast, wheat, milk, soy, artificial colors, flavors or preservatives Gluten Free
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.
Brand IP Statement(s)
Trusted since 1972 Windmill Natural Vitamins
FDA Statement of Identity
Dietary Supplement
General Statements
Pharmacist Recommended
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
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)The Ingredients in Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Tablet(s) Dosage formTablet Or Pill Amounts shown are per serving.
Vitamin C
Interacts with207 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 im...
Vitamin C monograph & interactionsOther (inactive) ingredients: Microcrystalline Cellulose, Hydroxypropyl Methyl Cellulose, Stearic Acid, Silicon Dioxide, Magnesium Stearate, Vegetable Coating, Polyethylene Glycol. These complete the product’s ingredient list but are not active constituents.
Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins Drug Interactions
HelloPharmacist Interaction Report
Windmill's Sustained Release C-500 contains vitamin C, which interacts with a number of medications.
The most serious documented concern is with estrogens—including birth control pills and hormone replacement therapy—where vitamin C may raise estrogen blood levels by up to 55% in some cases. This is a Moderate severity interaction.
Read the full breakdown — every affected drug type, severity by severity
Vitamin C also has Moderate interactions with several chemotherapy drugs (alkylating agents and antitumor antibiotics), where its antioxidant effects might reduce how well these cancer medications work. It can increase aluminum absorption from aluminum-containing compounds, and high doses may reduce warfarin (a blood thinner) effectiveness or increase the blood-thinning effect of levothyroxine (thyroid medication).
Moderate interactions are also documented with the antipsychotic fluphenazine, the HIV drug indinavir, and levothyroxine absorption.
Although vitamin C was checked against our data, these interactions span 207 individual medications. Use the search tool below to check your exact prescriptions before starting this supplement.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Sustained Release C-500 (Ascorbic Acid)?
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 checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in Sustained Release C-500 (Ascorbic Acid) interact with 207 drugs. Click any drug to see the details.
1 of the 1 ingredient in Sustained Release C-500 (Ascorbic Acid) interact with drugs. Each result below shows which ingredient is responsible. Vitamin C
Segesterone Acetate, Ethinyl EstradiolAnnovera
How Segesterone Acetate, Ethinyl Estradiol interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CEstrogens Moderate
Interaction Summary
Vitamin C might increase blood levels of estrogens.
Read the full Vitamin C + Segesterone Acetate, Ethinyl Estradiol interactionStreptozocinZanosar
How Streptozocin interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAlkylating Agents Moderate
Interaction Summary
Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
Read the full Vitamin C + Streptozocin interactionTemozolomideTemodar
How Temozolomide interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAlkylating Agents Moderate
Interaction Summary
Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
Read the full Vitamin C + Temozolomide interactionThiotepaTepadina, Thioplex
How Thiotepa interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAlkylating Agents Moderate
Interaction Summary
Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
Read the full Vitamin C + Thiotepa interactionTiboloneLivial
How Tibolone interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CEstrogens Moderate
Interaction Summary
Vitamin C might increase blood levels of estrogens.
Read the full Vitamin C + Tibolone interactionTigecyclineTygacil
How Tigecycline interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAntitumor Antibiotics Moderate
Interaction Summary
Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
Read the full Vitamin C + Tigecycline interactionTrabectedinYondelis
How Trabectedin interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAlkylating Agents Moderate
Interaction Summary
Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
Read the full Vitamin C + Trabectedin interactionValrubicinValstar
How Valrubicin interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAntitumor Antibiotics Moderate
Interaction Summary
Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
Read the full Vitamin C + Valrubicin interactionWarfarinWarfarin
How Warfarin interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CWarfarin (coumadin) Moderate
Interaction Summary
High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Read the full Vitamin C + Warfarin interactionWarfarin SodiumCoumadin, Panwarfin, Sofarin
How Warfarin Sodium interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CWarfarin (coumadin) Moderate
Interaction Summary
High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Read the full Vitamin C + Warfarin Sodium interactionDrospirenone, Ethinyl Estradiol, LevomefolateBeyaz
How Drospirenone, Ethinyl Estradiol, Levomefolate interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CEstrogens Moderate
Interaction Summary
Vitamin C might increase blood levels of estrogens.
Read the full Vitamin C + Drospirenone, Ethinyl Estradiol, Levomefolate interactionAcetaminophenChildren's Tylenol, Children's Tylenol Meltaways, Tylenol, Tylenol Ex Strength
How Acetaminophen interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen interactionAcetaminophen, AspirinGemnisyn
How Acetaminophen, Aspirin interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others), Aspirin Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Aspirin interactionAcetaminophen, Aspirin, CaffeineExcedrin, Excedrin Extra Strength, Excedrin Migraine
How Acetaminophen, Aspirin, Caffeine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others), Aspirin Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Aspirin, Caffeine interactionAcetaminophen, Brompheniramine, PhenylpropanolamineDimetapp Cold and Flu
How Acetaminophen, Brompheniramine, Phenylpropanolamine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Brompheniramine, Phenylpropanolamine interactionAcetaminophen, ButalbitalAxocet, Bancap, Bucet, Butex Forte, Esgic CF, Orbivan CF +5 more
How Acetaminophen, Butalbital interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Butalbital interactionAcetaminophen, Butalbital, CaffeineEsgic, Esgic Plus, Fiogesic, Fioricet, Repan, Tecnal +1 more
How Acetaminophen, Butalbital, Caffeine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Butalbital, Caffeine interactionAcetaminophen, Butalbital, Caffeine, CodeineEsgic with Codeine, Fioricet w/ Codeine
How Acetaminophen, Butalbital, Caffeine, Codeine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Butalbital, Caffeine, Codeine interactionAcetaminophen, Butalbital, CodeineBancap w/ Codeine
How Acetaminophen, Butalbital, Codeine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Butalbital, Codeine interactionAcetaminophen, Butalbital, Codeine PhosphatePhrenilin #3
How Acetaminophen, Butalbital, Codeine Phosphate interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Butalbital, Codeine Phosphate interactionAcetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, PhenylephrineHycomine Compound
How Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine interactionAcetaminophen, Caffeine, CodeineGesic C15, Gesic C30, Gesic C8, Lenoltec 1, Lenoltec 2, Lenoltec 3 +1 more
How Acetaminophen, Caffeine, Codeine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Caffeine, Codeine interactionAcetaminophen, Caffeine, Codeine, SalicylamideCodalan No.1, Codalan No.2, Codalan No.3
How Acetaminophen, Caffeine, Codeine, Salicylamide interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Caffeine, Codeine, Salicylamide interactionAcetaminophen, Caffeine, DihydrocodeineDHC Plus, Panlor DC, Panlor SS
How Acetaminophen, Caffeine, Dihydrocodeine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Caffeine, Dihydrocodeine interactionAcetaminophen, Caffeine, IsomethepteneMigralam
How Acetaminophen, Caffeine, Isometheptene interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Caffeine, Isometheptene interactionAcetaminophen, Caffeine, PyrilamineMidol Max Strength Menstrual
How Acetaminophen, Caffeine, Pyrilamine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Caffeine, Pyrilamine interactionAcetaminophen, Chlorpheniramine Maleate, Dextromethorphan HbrVicks Formula 44M Cough, Cold & Flu Relief
How Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan Hbr interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan Hbr interactionAcetaminophen, Chlorpheniramine, Codeine, PhenylephrineColrex
How Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine interactionAcetaminophen, Chlorpheniramine, DextromethorphanCoricidin II Extra Strength Cold and Flu
How Acetaminophen, Chlorpheniramine, Dextromethorphan interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Chlorpheniramine, Dextromethorphan interactionAcetaminophen, Chlorpheniramine, Dextromethorphan HydrobromideCoricidin HBP Maximum Strength Flu
How Acetaminophen, Chlorpheniramine, Dextromethorphan Hydrobromide interacts with Sustained Release C-500 (Ascorbic Acid) — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAcetaminophen (tylenol, Others) Minor
Interaction Summary
High-dose vitamin C might slightly prolong the clearance of acetaminophen.
Read the full Vitamin C + Acetaminophen, Chlorpheniramine, Dextromethorphan Hydrobromide interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Sustained Release C-500 (Ascorbic Acid) 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.
Vitamin C
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Brand information
Manufacturer and brand details for Sustained Release C-500 (Ascorbic Acid), from the product label.
Windmill Natural Vitamins
See all Windmill Natural Vitamins products- Name
- Windmill Health Products
- Street Address
- 10 Henderson Drive
- City
- West Caldwell
- State
- NJ
- ZipCode
- 07006
- Web Address
- www.windmillvitamins.com
Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins: Common Questions
Does Sustained Release C-500 (Ascorbic Acid) by Windmill Natural Vitamins interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Is this safe to take if I'm on birth control?
What side effects might I get from vitamin C?
Is it safe to take during pregnancy?
Can I take this with warfarin?
Does this actually work for vitamin C deficiency?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Sustained Release C-500 (Ascorbic Acid) is safe with your meds?
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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.
The Full Monographs Behind Sustained Release C-500 (Ascorbic Acid)’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Sources & How We Checked
Sustained Release C-500 (Ascorbic Acid)'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.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
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 51 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
- McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
- 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.
- Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
- Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
- 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
- Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
- Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
- Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
- 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/.
- Houston JB, Levy G. Drug biotransformation interactions in man VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218-21. PubMed
- 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
- Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671. DOI
- Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479. DOI
- Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166. DOI
- 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
- Domingo JL, Gomez M, Llobet JM, Richart C. Effect of ascorbic acid on gastrointestinal aluminum absorption (letter). Lancet 1991;338:1467.
- 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
- Partridge NA, Regnier FE, White JL, Hem SL. Influence of dietary constituents on intestinal absorption of aluminum. Kidney Int 1989;35:1413-7. PubMed
- Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413. DOI
- Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31. PubMed
- Dysken MW, Cumming RJ, Channon RA, Davis JM. Drug interaction between ascorbic acid and fluphenazine. JAMA 1979;241:2008. DOI
- Vihtamaki T, Parantainen J, Koivisto AM, et al. Oral ascorbic acid increases plasma oestradiol during postmenopausal hormone replacement therapy. Maturitas 2002;42:129-35. PubMed
- Slain D, Amsden JR, Khakoo RA, et al. Effect of high-dose vitamin C on the steady-state pharmacokinetics of the protease inhibitor indinavir in healthy volunteers. Pharmacotherapy 2005;25:165-70. PubMed
- Cheung MC, Zhao XQ, Chait A, et al. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol 2001;21:1320-6. PubMed
- Feetam CL, Leach RH, Meynell MJ. Lack of a clinically important interaction between warfarin and ascorbic acid. Toxicol Appl Pharmacol 1975;31:544-7. PubMed
- Weintraub M, Griner PF. Warfarin and ascorbic acid: lack of evidence for a drug interaction. Toxicol Appl Pharmacol 1974;28:53-6. PubMed
- Lee DH, Folsom AR, Harnack L, et al. Does supplemental vitamin C increase cardiovascular disease risk in women with diabetes? Am J Clin Nutr 2004;80:1194-200. PubMed
- Taylor EN, Stampfer MJ, Curhan GC. Dietary factors and the risk of incident kidney stones in men: new insights after 14 years of follow-up. J Am Soc Nephrol 2004;15:3225-32. PubMed
- Ward NC, Hodgson JM, Croft KD, et al. The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens 2005;23:427-34.. PubMed
- Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S. PubMed
- Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S. PubMed
- Fairweather-Tait S, Hickson K, McGaw B, et al. Orange juice enhances aluminium absorption from antacid preparation. Eur J Clin Nutr. 1994;48(1):71-3.
- Gruenwald, J., Graubaum, H. J., Busch, R., and Bentley, C. Safety and tolerance of ester-C compared with regular ascorbic acid. Adv.Ther. 2006;23(1):171-178.
- Rahimi, R., Nikfar, S., Rezaie, A., and Abdollahi, M. A meta-analysis on the efficacy and safety of combined vitamin C and E supplementation in preeclamptic women. Hypertens.Pregnancy. 2009;28(4):417-434. PubMed
- Einerson, B., Nathorn, C., Kitiyakara, C., Sirada, M., and Thamlikitkul, V. The efficacy of ascorbic acid in suboptimal responsive anemic hemodialysis patients receiving erythropoietin: a meta-analysis. J Med.Assoc.Thai. 2011;94 Suppl 1:S134-S146.
- Li, G., Li, L., Yu, C., and Chen, L. Effect of vitamins C and E supplementation on Helicobacter pylori eradication: a meta-analysis. Br.J Nutr 2011;106(11):1632-1637.
- Chen X, Shen L, Gu X, et al. High-dose supplementation with vitamin C--induced pediatric urolithiasis: the first case report in a child and literature review. Urology. 2014;84(4):922-4. PubMed
- Sattar A, Willman JE, Kolluri R. Possible warfarin resistance due to interaction with ascorbic acid: case report and literature review. Am J Health Syst Pharm. 2013;70(9):782-6. PubMed
- Yaich S, Chaabouni Y, Charfeddine K, et al. Secondary oxalosis due to excess vitamin C intake: a cause of graft loss in a renal transplant recipient. Saudi J Kidney Dis Transpl. 2014;25(1):113-6. PubMed
- Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. PubMed
- Rumbold A, Ota E, Nagata C, Shahrook S, Crowther CA. Vitamin C supplementation in pregnancy. Cochrane Database Syst Rev. 2015;(9):CD004072. PubMed
- Seo MS, Kim JK, Shim JY. High-dose vitamin C promotes regression of multiple pulmonary metastases originating from hepatocellular carcinoma. Yonsei Med J. 2015;56(5):1449-52. PubMed
- Skelin M, Lucijanic T, Amidzic Klaric D, et al. Factors Affecting Gastrointestinal Absorption of Levothyroxine: A Review. Clin Ther. 2017 Feb;39(2):378-403. PubMed
- Jiang K, Tang K, Liu H, Xu H, Ye Z, Chen Z. Ascorbic acid supplements and kidney stones incidence among men and women: a systematic review and meta-analysis. Urol J. 2019;16(2):115-120.
- Thomas S, Patel D, Bittel B, et al. Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial. JAMA Netw Open. 2 PubMed
- Giffen MA, McLemore JL. Hyperoxalosis Secondary to Intravenous Vitamin C Administration as a Non-Allopathic Treatment for Cancer. Acad Forensic Pathol 2019;9(1-2):118-126. PubMed
- Maike A, Sturgill D, Gallan A. Oxalate Nephropathy in a Renal Transplant Recipient After Receiving High Dose Ascorbic Acid. Am J Med Sci 2021. PubMed
- Shen ZY, Chen YR, Wang MC, Chang SS. High-dose vitamin C-induced acute oxalate nephropathy in a renal transplant recipient: a case report and literature review. Asian J Surg 2022. PubMed
- Yanase F, Spano S, Maeda A, et al. Mega-dose sodium ascorbate: a pilot, single-dose, physiological effect, double-blind, randomized, controlled trial. Crit Care 2023;27(1):371. PubMed
- Sharma Y, Sumanadasa S, Shahi R, et al. Efficacy and safety of vitamin C supplementation in the treatment of community-acquired pneumonia: a systematic review and meta-analysis with trial sequential analysis. Sci Rep 2024;14(1):11846. PubMed
- Pejcic AV, Petrovic NZ, Djordjic MD, Milosavljevic MN. Vitamin C Levels in Pregnant Women and the Efficacy of Vitamin C Supplements in Preventing Premature Rupture of Membranes: A Systematic Review and Meta-Analysis. Balkan Med J 2024;41(4):248-260. PubMed
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