Nuthroid Ingredients & Drug Interactions
What is this page for?
First and foremost: checking Nuthroid 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
Nuthroid is a dietary supplement by Cardiovascular Research with 5 active ingredients. Its ingredients are commonly taken for mental focus and alertness, coping with stress, fatigue and sleep loss.Based on those ingredients, 225 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Vitamin C, L-Tyrosine, ABgland Liver. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Nuthroid by Cardiovascular Research
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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 Nuthroid by Cardiovascular Research
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
Low disclosure
Nuthroid contains 5 active ingredients: L-Tyrosine (an amino acid precursor to thyroid hormone), Vitamin C (an antioxidant vitamin), Abgland Spleen, Bovine Glandular Complex, ABgland Liver (liver extract), and ABgland Thyroid. The product also includes inactive ingredients such as microcrystalline cellulose, gelatin, beef tissue, dicalcium phosphate, silicon dioxide, and magnesium stearate.
Does it work?
Strong evidence
L-Tyrosine is effective for phenylketonuria (PKU) and possibly effective for cognitive function and memory; evidence is insufficient for alcohol use disorder and dementia, and it appears possibly ineffective for athletic performance. Vitamin C is effective for vitamin C deficiency and possibly effective for anemia of chronic disease, atrial fibrillation, cataracts, and exercise-induced respiratory infections.
Liver Extract appears possibly ineffective for chronic fatigue syndrome; evidence is insufficient for hepatitis C. We do not hold effectiveness data for Abgland Spleen or ABgland Thyroid.
How safe is it?
Well-documented data
L-Tyrosine is generally well tolerated in healthy adults but isn't recommended for regular use without medical advice due to limited safety data. The most common side effects are fatigue, headache, heartburn, and nausea; larger doses can increase these risks.
Vitamin C is generally safe at normal dietary and supplement doses; very high doses (above 2 grams daily) can cause abdominal cramps, heartburn, diarrhea, nausea, and kidney stones in those prone to them. Liver Extract carries a general low risk for healthy adults in food amounts but can deliver high levels of vitamin A and iron and raises source-quality concerns — there's theoretical risk of contamination from raw animal liver, though no human BSE transfer from liver extract has been reported.
For L-Tyrosine, there isn't enough safety data during pregnancy and breastfeeding; for Vitamin C, normal amounts from food and prenatal vitamins are fine, but avoid high-dose supplements in pregnancy unless your doctor advises it, and avoid high-dose supplements while breastfeeding. Liver Extract should be avoided in pregnancy unless advised by your doctor due to high vitamin A content.
We do not hold pregnancy and breastfeeding data for Abgland Spleen or ABgland Thyroid.
Meds to double-check
Moderate interaction found
Before taking Nuthroid, check with your doctor or pharmacist if you take oral contraceptives or hormone replacement therapy (Vitamin C may increase estrogen levels), levodopa for Parkinson's disease (L-Tyrosine may reduce its effectiveness), thyroid hormone medication (L-Tyrosine may have additive effects; Vitamin C may increase absorption), warfarin or other blood thinners (high-dose Vitamin C and Liver Extract may reduce effectiveness), chemotherapy drugs, antipsychotics like fluphenazine, or iron supplements or medications.
The bottom line
Scorecard at a glanceFormula with limited ingredient disclosure with strong clinical evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.
Nuthroid may appeal to those interested in glandular and amino acid support, but you should not start it if you take levodopa, thyroid medications, warfarin, certain chemotherapy drugs, or hormonal birth control without checking first. If you take any prescription medication — especially blood thinners, thyroid medications, or HIV antivirals — talk it over with your doctor or pharmacist before adding this product.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 3 of 5 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Mar 22, 2023.
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 Nuthroid, straight from the product label.
| Brand | Cardiovascular Research |
|---|---|
| Barcode (UPC) | 696859131356 |
| Net contents | 60 Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Mar 22, 2023 |
| DSLD ID | 283443 |
| Product type | Non-nutrient/non-botanical |
| Supplement form | Capsule |
| Dietary claims / uses | Nutrient, All Other |
| Intended target group(s) | Adult (18 - 50 Years), No Allergies, Gluten 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 Nuthroid by Cardiovascular Research, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Tyrosine | 30 mg | -- |
| Vitamin C | 65 mg | 70% |
| Abgland Spleen | 0 NP | -- |
| Bovine Glandular Complex | 125 mg | -- |
| ABgland Liver | 0 NP | -- |
| ABgland Thyroid | 0 NP | -- |
Other ingredients: Microcrystalline Cellulose, Gelatin, Beef Tissue, Dicalcium Phosphate, Silicon Dioxide, Magnesium Stearate
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.
FDA Statement of Identity
Dietary Supplement
Formula
Nuthroid is a scientifically-designed food supplement containing nucleo-proteins, vitamin C, and the amino acid tyrosine.
Formulation
Contains no binders, soy, yeast, egg, or other common allergens.
Gluten free, casein free
Suggested/Recommended/Usage/Directions
Directions Take two capsules daily, or as directed by a physician.
General Statements
Ecological Formulas
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Nuthroid by Cardiovascular Research 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 Nuthroid by Cardiovascular Research
These are the 5 active ingredients this product is made of. Select any to open its full monograph.
Serving size2 Capsule(s) Dosage formCapsule 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.
L-Tyrosine
Interacts with21 drugs
L-tyrosine is an amino acid your body uses to make brain chemicals like dopamine and norepinephrine. Some studies suggest it may help mental performan...
L-Tyrosine monograph & interactionsVitamin 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 & interactionsBovine Glandular Complex
- › Abgland Spleen
- › ABgland Liver
- › ABgland Thyroid
Other (inactive) ingredients: Microcrystalline Cellulose, Gelatin, Beef Tissue, Dicalcium Phosphate, Silicon Dioxide, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.
Nuthroid by Cardiovascular Research Drug Interactions
HelloPharmacist Interaction Report
Nuthroid by Cardiovascular Research contains ingredients with documented interactions: L-Tyrosine, Vitamin C, and Liver Extract.
The most serious interaction is Moderate severity — Vitamin C can increase estrogen levels by up to 55% when taken with oral contraceptives or hormone replacement therapy, potentially raising the risk of estrogen-related side effects.
Read the full breakdown — every affected drug type, severity by severity
L-Tyrosine may reduce the effectiveness of levodopa (a Parkinson's medication) and could have additive effects if you're taking thyroid hormone medication. Vitamin C interacts with several drug types: it can reduce the effectiveness of warfarin (a blood thinner) at high doses, may interfere with certain chemotherapy drugs and antipsychotics, and can increase absorption of levothyroxine (thyroid medication).
It also increases aluminum absorption from aluminum-containing compounds and may modestly reduce indinavir (an HIV medication) levels.
Liver Extract may contain vitamin K, which theoretically could reduce warfarin's effectiveness, and can contribute additional iron intake if you're already taking iron supplements or medications — a concern mainly at high doses or with prolonged use.
We could not check two ingredients: Abgland Spleen and ABgland Thyroid. Altogether, these interactions span 225 individual medications.
Use the search tool on this page to check your exact medications before starting.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Nuthroid?
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 Nuthroid interact with 225 drugs. Click any drug to see the details.
3 of the 5 ingredients in Nuthroid interact with drugs. Each result below shows which ingredient is responsible. Vitamin C L-Tyrosine ABgland Liver
Alginic Acid, Aluminum HydroxideRafton
How Alginic Acid, Aluminum Hydroxide interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Alginic Acid, Aluminum Hydroxide interactionAltretamineHexalen
How Altretamine interacts with Nuthroid — 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 + Altretamine interactionAluminum Acetate, Benzethonium ChlorideBuro-Sol Otic Solution
How Aluminum Acetate, Benzethonium Chloride interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum Acetate, Benzethonium Chloride interactionAluminum ChlorideAluminum Chloride, Anhydrol Forte, Driclor, Drysol
How Aluminum Chloride interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum Chloride interactionAluminum HydroxideAlu-Cap, Amphojel, Gaviscon
How Aluminum Hydroxide interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum Hydroxide interactionAluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #2
How Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAspirin, Aluminum Moderate
Interaction Summary
Acidification of the urine by vitamin C might increase aspirin levels.
Read the full Vitamin C + Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide interactionAluminum Hydroxide, Aspirin, Magnesium HydroxideAscriptin
How Aluminum Hydroxide, Aspirin, Magnesium Hydroxide interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAspirin, Aluminum Moderate
Interaction Summary
Acidification of the urine by vitamin C might increase aspirin levels.
Read the full Vitamin C + Aluminum Hydroxide, Aspirin, Magnesium Hydroxide interactionAluminum Hydroxide, Magnesium Hydroxide (otc Drug)Maalox, Mucogel
How Aluminum Hydroxide, Magnesium Hydroxide (otc Drug) interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum Hydroxide, Magnesium Hydroxide (otc Drug) interactionAluminum Hydroxide, Magnesium Hydroxide, Simethicone (otc Drug)Mylanta
How Aluminum Hydroxide, Magnesium Hydroxide, Simethicone (otc Drug) interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum Hydroxide, Magnesium Hydroxide, Simethicone (otc Drug) interactionAluminum, CalciumDomeboro
How Aluminum, Calcium interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum, Calcium interactionAluminum, Magnesium (otc Drug)Almagel
How Aluminum, Magnesium (otc Drug) interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum, Magnesium (otc Drug) interactionAluminum, Magnesium Hydroxide (otc Drug)Wingel
How Aluminum, Magnesium Hydroxide (otc Drug) interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAluminum Moderate
Interaction Summary
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Read the full Vitamin C + Aluminum, Magnesium Hydroxide (otc Drug) interactionAspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #3
How Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
Vitamin CAspirin, Aluminum Moderate
Interaction Summary
Acidification of the urine by vitamin C might increase aspirin levels.
Read the full Vitamin C + Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interactionBazedoxifene Acetate, Conjugated EstrogensDuavee
How Bazedoxifene Acetate, Conjugated Estrogens interacts with Nuthroid — 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 + Bazedoxifene Acetate, Conjugated Estrogens interactionBendamustineBelrapzo, Treanda, Vivimusta
How Bendamustine interacts with Nuthroid — 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 + Bendamustine interactionBendamustine HydrochlorideBendeka
How Bendamustine Hydrochloride interacts with Nuthroid — 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 + Bendamustine Hydrochloride interactionBenserazide, LevodopaMadopar, Prolopa
How Benserazide, Levodopa interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Benserazide, Levodopa interactionBleomycinBlenoxane
How Bleomycin interacts with Nuthroid — 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 + Bleomycin interactionBusulfanBusulfex, Myleran
How Busulfan interacts with Nuthroid — 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 + Busulfan interactionCarbidopa, LevodopaDhivy, Rytary, Sinemet, Sinemet CR
How Carbidopa, Levodopa interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Carbidopa, Levodopa interactionCarbidopa, Levodopa, EntacaponeStalevo
How Carbidopa, Levodopa, Entacapone interacts with Nuthroid — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Carbidopa, Levodopa, Entacapone interactionCarboplatinParaplatin
How Carboplatin interacts with Nuthroid — 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 + Carboplatin interactionCarmustineBiCNU, Gliadel, Gliadel Wafer
How Carmustine interacts with Nuthroid — 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 + Carmustine interactionChlorambucilLeukeran
How Chlorambucil interacts with Nuthroid — 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 + Chlorambucil interactionCisplatinPlatinol-AQ
How Cisplatin interacts with Nuthroid — 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 + Cisplatin interactionConjugated EstrogensCenestin, Enjuvia, Premarin, Premarin Vaginal Cream
How Conjugated Estrogens interacts with Nuthroid — through 2 ingredients. Tap an ingredient for the detail:
Vitamin CEstrogens Moderate
Interaction Summary
Vitamin C might increase blood levels of estrogens.
Read the full Vitamin C + Conjugated Estrogens interactionL-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Conjugated Estrogens interactionConjugated Estrogens, Medroxyprogesterone AcetatePremplus, Prempro
How Conjugated Estrogens, Medroxyprogesterone Acetate interacts with Nuthroid — 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 + Conjugated Estrogens, Medroxyprogesterone Acetate interactionConjugated Estrogens, MeprobamatePMB 200, PMB 400
How Conjugated Estrogens, Meprobamate interacts with Nuthroid — 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 + Conjugated Estrogens, Meprobamate interactionConjugated Estrogens, MethyltestosteronePremarin with Methyltestosterone
How Conjugated Estrogens, Methyltestosterone interacts with Nuthroid — 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 + Conjugated Estrogens, Methyltestosterone interactionCyclophosphamideCytoxan, Neosar
How Cyclophosphamide interacts with Nuthroid — 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 + Cyclophosphamide interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Nuthroid 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.
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.
L-Tyrosine
Levodopa
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Tyrosine and levodopa compete for absorption in the proximal duodenum by the large neutral amino acid (LNAA) transport system. Advise patients to separate doses of tyrosine and levodopa by at least 2 hours.
Thyroid Hormone
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Tyrosine is a precursor to thyroxine and might increase levels of thyroid hormones.
ABgland Liver
Iron
Liver extract can contain heme iron. Taking liver extract with iron-containing medications or supplements may increase total iron intake and could increase the risk of gastrointestinal adverse effects or excessive iron accumulation. The risk is greater with high doses, prolonged use, or in individuals with hemochromatosis or another iron-overload disorder. Review the iron content of the liver extract and the total elemental iron dose. Avoid unnecessary duplicate iron supplementation and consider monitoring ferritin and transferrin saturation when clinically appropriate.
Warfarin (Coumadin)
Liver extract products may contain small and variable amounts of vitamin K. Theoretically, starting, stopping, or substantially changing the amount of liver extract used could reduce the anticoagulant effect of warfarin and lower the INR. However, this interaction has not been directly studied or reported in humans, and the vitamin K content of liver extract products is generally not standardized. Consider monitoring the INR after a meaningful change in liver extract use.
Brand information
Manufacturer and brand details for Nuthroid, from the product label.
Cardiovascular Research
See all Cardiovascular Research products- Name
- Cardiovascular Research, LTD.
- Street Address
- 1061-B Shary Circle
- City
- Concord
- State
- CA
- ZipCode
- 94518
Nuthroid by Cardiovascular Research: Common Questions
Does Nuthroid by Cardiovascular Research interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Who is L-Tyrosine actually effective for?
Can I take this while on birth control?
What are the most common side effects of L-Tyrosine?
Is it safe to take this in pregnancy?
Can high doses of Vitamin C in this product cause problems?
What should I know about the Liver Extract in this product?
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.
The Full Monographs Behind Nuthroid’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Tyrosine
Interacts with 21 drugsL-tyrosine is an amino acid your body uses to make brain chemicals like dopamine and norepinephrine. Some studies suggest it may help mental performance during short-term stress, sleep loss,...
Read the full Tyrosine monograph → Herb & supplement monographVitamin C
Interacts with 207 drugsVitamin 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 monographLiver Extract
Interacts with 3 drugsLiver extract is a dried or concentrated form of animal liver that is naturally rich in iron, vitamin B12, vitamin A, and other nutrients. It was once used to treat certain anemias before pu...
Read the full Liver Extract monograph →Sources & How We Checked
Nuthroid'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 59 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.
Tyrosine 4 references
- Meyer JS, Welch KM, Deshmukh VD, et al. Neurotransmitter precursor amino acids in the treatment of multi-infarct dementia and Alzheimer's disease. J Amer Geriat Soc 1977;25:289-98.
- DiPiro JT, Talbert RL, Yee GC, et al; eds. Pharmacotherapy: A pathophysiologic approach. 4th ed. Stamford, CT: Appleton & Lange, 1999.
- Wood DR, Reimherr FW, Wender PH. Amino acid precursors for the treatment of attention deficit disorder, residual type. Psychopharmacol Bull 1985;21:146-9.
- van Spronsen FJ, van Rijn M, Bekhof J. Phenylketonuria: tyrosine supplementation in phenylalanine-restricted diets. Am J Clin Nutr 2001;73:153-7. PubMed
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
Liver Extract 4 references
- Lewis CJ. Letter to reiterate certain public health and safety concerns to firms manufacturing or importing dietary supplements that contain specific bovine tissues. FDA. Available at: www.cfsan.fda.gov/~dms/dspltr05.html.
- Kaslow JE, Rucker L, Onishi R. Liver extract-folic acid-cyanocobalamin vs placebo for chronic fatigue syndrome. Arch Intern Med 1989;149:2501-3. DOI
- Ebinuma, H., Saito, H., Tada, S., Masuda, T., Kamiya, T., Nishida, J., Yoshioka, M., and Ishii, H. Additive therapeutic effects of the liver extract preparation mixture adelavin-9 on interferon-beta treatment for chronic hepatitis C. Hepatogastroenterolog
- Saito, H., Ebinuma, H., Tada, S., Tsunematsu, S., Atsukawa, K., Masuda, T., Tsuchiya, M., and Ishii, H. Enhancing effect of the liver extract and flavin adenin dinucleotide mixture on anti-viral efficacy of interferon in patients with chronic hepatitis C. PubMed
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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.
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