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

Cinnamon 400 Ingredients & Drug Interactions

by ProCaps Laboratories

Cinnamon 400 label
See full label image
Capsule Category: Botanical With Nutrients
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 Cinnamon 400 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

Cinnamon 400 is a dietary supplement by ProCaps Laboratories with 2 active ingredients. Its ingredients are commonly taken for blood sugar support, digestive upset, antioxidant support.Based on those ingredients, 554 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Cinnamon Bark Extract, Vitamin C. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Cinnamon 400 by ProCaps Laboratories

Ask about any prescription or over-the-counter medication and we check it for interactions with Cinnamon 400 by ProCaps Laboratories — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Cinnamon 400 by ProCaps Laboratories

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 4 of its 4 active ingredients.
  • “Cinnamon Bark Extract” is listed as a grouped ingredient — the label gives one combined amount (400 mg) without saying how much of each component you get.

Cinnamon 400 contains 4 active ingredients: cinnamon bark extract (which is itself a blend of component parts), vitamin C, flavones, and proanthocyanidins. The cinnamon bark extract is the primary active ingredient in this product.

Vitamin C supports immune function and collagen formation. The other inactive ingredients are plant cellulose and natural flavoring.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Vitamin C's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: supports healthy blood sugar balance and insulin metabolism.
  • We looked for evidence on: Diabetes, Impaired glucose tolerance (prediabetes), Dyslipidemia, Glycemic control, Metabolic syndrome, Insulin sensitivity.
  • The closest evidence on file: Vitamin C is rated "Insufficient Reliable Evidence To Rate" for Diabetes (Natural Medicines).

The evidence we hold on file is for vitamin C only. Vitamin C is effective for preventing and treating vitamin C deficiency.

It is possibly effective for anemia of chronic disease, atrial fibrillation, cataracts, and exercise-induced respiratory infections. We do not hold effectiveness data for the cinnamon bark extract, flavones, or proanthocyanidins in this product.

The evidence, ingredient by ingredient Cassia Cinnamon Vitamin C

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin C is generally well tolerated at normal dietary and supplement doses. At higher doses—especially above 2 grams daily—side effects can occur: abdominal cramps, heartburn, diarrhea, nausea, and headache are the most common.

People prone to kidney stones should be cautious, as high-dose vitamin C increases that risk. Rare serious effects from very high intravenous doses include kidney damage and false lab results.

The safety data on vitamin C advises against high-dose supplements in pregnancy unless your doctor recommends it; normal amounts from food and prenatal vitamins are considered safe. During breastfeeding, recommended dietary amounts are safe, but avoid high-dose supplements without medical guidance.

We hold no pregnancy or breastfeeding safety data for the other ingredients in this product.

Side effects, ingredient by ingredient Cassia Cinnamon Vitamin C

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Vitamin C.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; cancer treatments.
  • For scale: 207 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.

Check before starting if you take estrogens (birth control or hormone therapy), blood thinners like warfarin, levothyroxine (thyroid medication), chemotherapy drugs (especially alkylating agents or antitumor antibiotics), indinavir (HIV medication), fluphenazine (antipsychotic), or aluminum-containing compounds. All of these interactions are Moderate severity.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

If you take birth control pills, hormone replacement therapy, blood thinners, thyroid medication, or chemotherapy, check with your pharmacist before starting this product. The vitamin C content can shift how those medications work in your body.

Altogether, these interactions span 207 individual medications. For most people taking no prescription drugs, vitamin C at these doses is generally well tolerated.

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

Assessment coverage: 1 of 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jul 24, 2025.

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 Cinnamon 400, straight from the product label.

Brand ProCaps Laboratories
Barcode (UPC) 797210
Net contents 360 Easy-To-Swallow Capsule(s)
Market status On market
Date entered into DSLD Jul 24, 2025
DSLD ID 331530
Product type Botanical With Nutrients
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), No Allergies, Gluten Free, Dairy Free, Sugar Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Cinnamon 400 by ProCaps Laboratories, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
360
UPC/BARCODE
797210
IngredientAmount% DV
Flavones200 mg--
Cinnamon Bark Extract400 mg--
Vitamin C45 mg50%
Proanthocyanidins100 mg--
Type A Polymers100 mg--

Other ingredients: Plant Cellulose, Natural

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.
Suggested/Recommended/Usage/Directions

Suggested Use Consume one or more capsules daily. You can increase your intake as required or as recommended by your physician.

General Statements

For questions about the use of this product call 800.800.1200. Questions? Reorders? 800.800.1200 www.procapslabs.com Andrew Lessman

Formulation

Since 1979, Unsurpassed purity, quality and efficacy. 100% Solar production Zero-carbon footprint 100% Solar

Supports healthy blood sugar balance and insulin metabolism

Contains no additives or common allergens Contains no milk, soy, yeast, wheat, gluten, sodium, salt, sugar, fat, cholesterol, color, preservative, common allergens, genetically modified (GMO) ingredients or manufacturing additives.

FDA Statement of Identity

Dietary Supplement

Formula

Cinnamon 400 offers a unique concentrated blend of standardized extracts of cinnamon bark delivering the powerful protective compounds naturally present in this respected spice. For centuries, cinnamon has been sought after, not only for its distinctive flavor, but also for its health-promoting properties. In fact, cinnamon remains one of the oldest herbal remedies used in traditional Chinese medicine. Recently, cinnamon has gained popularity for its ability to help support healthy blood sugar balance and glucose metabolism. Research attributes these benefits to the powerful activity of the Type-A polyphenols present in cinnamon bark extract. Our Cinnamon 400 delivers a comprehensive standardized blend of polyphenols from three unique cinnamon extracts. As with all plant-based supplements, there is more to making a quality cinnamon product than placing some ordinary, powdered cinnamon into a pill. To receive the benefits of cinnamon, one must always seek standardized extracts of cinnamon bark delivering beneficial levels of their key protective compounds. Our unique, concentrated blend of these distinct standardized extracts of cinnamon bark assures the most comprehensive protection from this remarkable natural ingredient.

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)

Copyright 2024 ProCaps Laboratories

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

See for yourself

Cinnamon 400 by ProCaps Laboratories label

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

Cinnamon 400 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 Cinnamon 400 by ProCaps Laboratories

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

Serving size1 Capsule(s) Dosage formCapsule Servings per container360 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.

Cinnamon Bark Extract

Interacts with
442 drugs
400 mg per serving Form: Cinnamomum cassia Bark Extract

Cassia cinnamon is the common, inexpensive cinnamon used in cooking, and it is also taken as a supplement, most often for blood sugar support. The evi...

Cinnamon Bark Extract monograph & interactions
  • › Flavones
  • › Proanthocyanidins
  • › Type A Polymers

Vitamin C

Interacts with
207 drugs
45 mg per serving Form: Calcium Ascorbate, Calcium Palmitate

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

Other (inactive) ingredients: Plant Cellulose, Natural. These complete the product’s ingredient list but are not active constituents.

Interaction report

Cinnamon 400 by ProCaps Laboratories Drug Interactions

Want to check YOUR meds against Cinnamon 400?

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
554Drugs
521 Moderate 33 Minor

Ingredients driving the most interactions

Cinnamon Bark Extract 442
Vitamin C 207

Individual Drug Interactions

The ingredients in Cinnamon 400 interact with 554 drugs. Click any drug to see the details.

2 of the 2 ingredients in Cinnamon 400 interact with drugs. Each result below shows which ingredient is responsible. Cinnamon Bark Extract Vitamin C

Each ingredient & the kinds of drugs it affects

For each ingredient in Cinnamon 400 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.

Cinnamon Bark Extract2 drug types · 442 drugs

Antidiabetes Drugs

Theoretically, cassia cinnamon may have additive effects with antidiabetes drugs.
Cassia cinnamon may lower blood glucose levels, and have additive effects in patients treated with antidiabetic agents. Dose adjustments to diabetes medications might be necessary.

Likelihood Possible Evidence B
Hepatotoxic Drugs

Theoretically, large doses of cassia cinnamon might cause additive effects when used with hepatotoxic drugs.
There is some concern that ingesting large amounts of cassia cinnamon for an extended duration might cause hepatotoxicity in some people. Cassia cinnamon contains coumarin, which can cause hepatotoxicity in animal models. In humans, very high doses of coumarin from 50-7000 mg/day can result in hepatotoxicity that resolves when coumarin use is discontinued. Lower amounts might also cause liver problems in sensitive people, such as those with liver disease or those taking potentially hepatotoxic agents.

Likelihood Possible Evidence D
Cinnamon Bark 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
The maker

Brand information

Manufacturer and brand details for Cinnamon 400, from the product label.

ProCaps Laboratories

See all ProCaps Laboratories products
Name
ProCaps Labs
City
Henderson
State
NV
ZipCode
89011
Phone Number
800.800.1200
Web Address
www.ProCapsLabs.com
Pharmacist Counseling Corner

Cinnamon 400 by ProCaps Laboratories: Common Questions

Does Cinnamon 400 by ProCaps Laboratories interact with any medications?
Yes. Based on its ingredients, Cinnamon 400 has a known interaction with 554 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Cinnamon 400 contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Will this interfere with my birth control?
The vitamin C in this product can increase blood levels of estrogens found in oral contraceptives, potentially by up to 55% in some cases. Talk to your pharmacist or doctor about whether this product is right for you if you use hormonal birth control.
Can I take this if I'm on warfarin (Coumadin)?
No, not without checking with your pharmacist first. Vitamin C can reduce how well warfarin works by lowering its absorption. Your doctor may need to adjust your dose or monitor you more closely.
What side effects might I notice from the vitamin C?
At the doses in typical supplements, side effects are uncommon. If they do occur, they're usually mild: abdominal cramps, heartburn, diarrhea, nausea, or headache. These are more likely if you take very high doses (above 2 grams daily). If you're prone to kidney stones, high-dose vitamin C increases that risk.
Is it safe to take this while pregnant or breastfeeding?
Normal amounts of vitamin C from food and prenatal vitamins are safe during pregnancy. For supplements, there isn't enough data to know if this product is safe, so talk with your doctor or pharmacist before taking it. During breastfeeding, recommended dietary amounts are safe, but avoid high-dose supplements without medical guidance.
What does the cinnamon bark extract in this do?
We don't hold effectiveness data for cinnamon bark extract on file. We can tell you what's in the product, but for what it's marketed to do, I'd recommend asking your pharmacist or checking the brand's label.
Does this product have fillers?
The inactive ingredients are plant cellulose and natural flavoring — these are standard binders and flavorings used in capsules, not fillers in the sense of inert bulk. The product is straightforward in its ingredient list.

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.

Cinnamon 400 label
Go deeper

The Full Monographs Behind Cinnamon 400’s Ingredients

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

Herb & supplement monograph

Cassia Cinnamon

Interacts with 442 drugs

Cassia cinnamon is the common, inexpensive cinnamon used in cooking, and it is also taken as a supplement, most often for blood sugar support. The evidence for its health benefits is mixed a...

Read the full Cassia Cinnamon monograph → 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 →
Sources

Sources & How We Checked

Cinnamon 400'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 71 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.

Cassia Cinnamon 20 references
  1. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
  2. Khan A, Safdar M, Ali Khan M, et al. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care 2003;26:3215-8. PubMed
  3. De Benito V, Alzaga R. Occupational allergic contact dermatitis from cassia (Chinese cinnamon) as a flavouring agent in coffee. Contact Dermatitis 1999;40:165. PubMed
  4. Drake TE, Maibach HI. Allergic contact dermatitis and stomatitis caused by a cinnamic aldehyde-flavored toothpaste. Arch Dermatol 1976;112:202-3.
  5. Press release. Cinnamon capsules to reduce blood sugar are medicinal products! Efficacy has not been scientifically proven - some products contain high levels of coumarin. Federal Institute of Risk Assessment (BfM), Germany, November 11, 2006. Available a
  6. Felter SP, Vassallo JD, Carlton BD, Daston GP. A safety assessment of coumarin taking into account species-specificity of toxicokinetics. Food Chem Toxicol 2006;44:462-75. PubMed
  7. Crawford P. Effectiveness of cinnamon for lowering hemoglobin A1C in patients with type 2 diabetes: a randomized, controlled trial. J Am Board Fam Med 2009;22:507-12. PubMed
  8. Akilen, R., Tsiami, A., Devendra, D., and Robinson, N. Glycated haemoglobin and blood pressure-lowering effect of cinnamon in multi-ethnic Type 2 diabetic patients in the UK: a randomized, placebo-controlled, double-blind clinical trial. Diabet.Med. 2010; PubMed
  9. Lu T, Sheng H Wu J Cheng Y Zhu J Chen Y. Cinnamon extract improves fasting blood glucose and glycosylated hemoglobin level in Chinese patients with type 2 diabetes. Nutr Res. 2012;32(6):408-412. PubMed
  10. Choi, J., Lee, K. T., Ka, H., Jung, W. T., Jung, H. J., and Park, H. J. Constituents of the essential oil of the Cinnamomum cassia stem bark and the biological properties. Arch Pharm Res 2001;24(5):418-423.
  11. Altschuler JA, Casella SJ, MacKenzie TA, Curtis KM. The effect of cinnamon on A1C among adolescents with type 1 diabetes. Diabetes Care 2007;30(4):813-6. PubMed
  12. Stoecker BR, Zhan Z, Luo R, et al. Cinnamon extract lowers blood glucose in hyperglycemic subjects. FASEB J. 2010;22:722.1 (Abstract only). DOI
  13. Admani S, Hill H, Jacob SE. Cinnamon Sugar Scrub Dermatitis: "Natural" Is Not Always Best. Pediatr Dermatol. 2017;34(1):e42-e43. PubMed
  14. Isaac-Renton M, Li MK, Parsons LM. Cinnamon spice and everything not nice: many features of intraoral allergy to cinnamic aldehyde. Dermatitis. 2015;26(3):116-21. PubMed
  15. Vandersall A, Katta R. Eyelid dermatitis as a manifestation of systemic contact dermatitis to cinnamon. Dermatitis. 2015 Jul-Aug;26(4):189. PubMed
  16. Wickenberg J, Lindstedt S, Nilsson J, Hlebowicz J. Cassia cinnamon does not change the insulin sensitivity or the liver enzymes in subjects with impaired glucose tolerance. Nutr J 2014 Sep 24;13:96. PubMed
  17. Brancheau D, Patel B, Zughaib M. Do cinnamon supplements cause acute hepatitis? Am J Case Rep 2015;16:250-4. PubMed
  18. Shekarchizadeh-Esfahani P, Heydarpour F, Izadi F, Jalili C. The effect of cinnamon supplementation on liver enzymes in adults: A systematic review and meta-analysis of randomized controlled trials. Complement Ther Med 2021;58:102699. PubMed
  19. Bernaola J, Valverde-Monge M, Otal-Buesa M, Cullen D, Heras-Mendaza F. Cinnamon allergic contact cheilitis. Contact Dermatitis 2023;88(5):418-419. PubMed
  20. Patel K, Howard M, Tate B. Cheilitis caused by allergic contact dermatitis to cinnamon in chai tea: A case report. Contact Dermatitis 2023;88(3):239-240. PubMed

See these in context on the Cassia Cinnamon monograph →

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
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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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