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Dietary supplement

Chitosan 400 mg Ingredients & Drug Interactions

by tnvitamins

Chitosan 400 mg label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Chitosan 400 mg 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

Chitosan 400 mg is a dietary supplement by tnvitamins with 1 active ingredient. Its ingredients are commonly taken for weight management, lowering cholesterol, wound care.Based on those ingredients, 3 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Chitosan. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Chitosan 400 mg by tnvitamins

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

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HelloPharmacist Scorecard of Chitosan 400 mg by tnvitamins

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

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 16, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: chitosan, a compound derived from shellfish shells. Chitosan is marketed to support weight management and various aspects of recovery and heart health.

The capsule itself is made with gelatin, cellulose, and vegetable magnesium stearate—inactive ingredients that help form and stabilize the tablet.

Does it work?

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

We hold no graded evidence for this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: dietary fiber supplement.
  • Our graded evidence for these ingredients doesn't cover that particular purpose.

The evidence on chitosan is mixed. It's rated possibly effective for obesity and postoperative recovery (the healing period after surgery), and possibly effective for high blood pressure.

However, for Crohn disease and dry eye, the data we hold shows insufficient reliable evidence to rate it one way or the other. Talk with your doctor about whether chitosan fits your particular situation.

The evidence, ingredient by ingredient Chitosan

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.

Chitosan is generally well tolerated in the short term, though the quality of long-term safety data is limited. The most common side effects are constipation, diarrhea, bloating, nausea, and stomach discomfort.

A few people have reported a dry throat or fatty stools. One person with kidney failure reported itching during treatment, though it's unclear whether chitosan caused it.

Because chitosan comes from shellfish, it's a concern for anyone with a shellfish allergy. Not enough safety data exists during pregnancy or while breastfeeding.

The safety information advises against use in both situations. Talk with your doctor or pharmacist before taking this product if you're pregnant, planning to become pregnant, or breastfeeding.

Side effects, ingredient by ingredient Chitosan

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 — Chitosan.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 3 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before you start this product, check with your doctor or pharmacist if you take warfarin or other blood thinners—chitosan may raise your bleeding risk. Also confirm if you're taking acyclovir or other antivirals for herpes or similar infections, since chitosan can reduce how much of the drug your body absorbs and may make treatment less effective.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Chitosan may be worth considering if you're looking for support with weight management or post-surgery recovery and your doctor thinks it's appropriate. However, if you take warfarin, acyclovir, or any other blood thinners or antivirals, check with your own pharmacist or doctor before starting.

Pregnant or breastfeeding women should avoid it. Stomach upset and constipation are common, and anyone allergic to shellfish should not take it.

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 Apr 23, 2020.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Chitosan 400 mg, straight from the product label.

Brand tnvitamins
Barcode (UPC) 095234101319
Net contents 120 Capsule(s)
Market status On market
Date entered into DSLD Apr 23, 2020
DSLD ID 217722
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses Nutrient, All Other
Intended target group(s) Adult (18 - 50 Years), Women (not pregnant or lactating), Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Chitosan 400 mg by tnvitamins, 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:
2 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
Servings per container
60
UPC/BARCODE
095234101319
IngredientAmount% DV
Total Carbohydrates1 Gram(s)--
Chitosan800 mg--

Other ingredients: Gelatin, Cellulose, Vegetable Magnesium Stearate

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formula

Fantastic dietary fiber

FDA Statement of Identity

Dietary Supplement

Precautions

Contains shellfish (crab and shrimp) ingredients.

Warning: This product is derived from shellfish. Do not take it if you are allergic or sensitive to any form of shellfish.

Use during pregnancy, lactation or by children is not recommended.

Use during pregnancy, lactation or by children is not recommended.

Caution: Pregnant or lactating women should consult a doctor before use.

If you are under medical supervision, please consult a doctor before use. Discontinue use and consult a doctor if any adverse reactions occur.

Keep out of reach of children.

Formulation

Free of: Gluten, wheat, yeast, milk, lactose, soy, artificial color, artificial flavor, artificial sweetener, preservatives. Non GMO.

Suggested/Recommended/Usage/Directions

Directions: As a dietary supplement, take two (2) capsules 30 minutes prior to lunch and two (2) more prior to dinner. Always take with eight (8) ounces of liquid, or as directed by a health care professional.

General Statements

Reorder tnvitamins.com 800-645-4446

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

See for yourself

Chitosan 400 mg by tnvitamins label

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

Chitosan 400 mg 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 Chitosan 400 mg by tnvitamins

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule Servings per container60 Amounts shown are per serving.

Chitosan

Interacts with
3 drugs
800 mg per serving Form: Shellfish

Chitosan is a fiber-like substance made from the shells of shrimp, crabs, and other shellfish, often marketed for weight loss and cholesterol. The evi...

Chitosan monograph & interactions

Other (inactive) ingredients: Gelatin, Cellulose, Vegetable Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Chitosan 400 mg by tnvitamins Drug Interactions

Want to check YOUR meds against Chitosan 400 mg?

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
3Drugs
3 Moderate

Ingredients driving the most interactions

Chitosan 3

Individual Drug Interactions

The ingredients in Chitosan 400 mg interact with 3 drugs. Click any drug to see the details.

1 of the 1 ingredient in Chitosan 400 mg interact with drugs. Each result below shows which ingredient is responsible. Chitosan

Each ingredient & the kinds of drugs it affects

For each ingredient in Chitosan 400 mg 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.

Chitosan2 drug types · 3 drugs

Acyclovir (Zovirax)

Chitosan can reduce the absorption of acyclovir, potentially increasing the risk for treatment failure.
Clinical research in humans shows that taking chitosan along with acyclovir 200 mg reduces acyclovir absorption. Concomitant administration of chitosan 400 mg or 1000 mg reduced the acyclovir area under the curve (AUC) and peak plasma concentration by about 30% and 40%, respectively, compared with control. Concomitant administration with chitosan 1000 mg also increased time to peak concentration from 1 hour to 2 hours. In vitro research suggests that the mechanism for reduced absorption is due to acyclovir entrapment in chitosan-mucus complexes, which reduces intestinal absorption.

Likelihood Possible Evidence B
Warfarin (Coumadin)

Theoretically, chitosan might increase the risk of bleeding when taken with warfarin.
In a case report, a patient taking warfarin had a significantly increased international normalized ratio (INR) after starting chitosan 1200 mg daily. The INR normalized after chitosan was discontinued and vitamin K was administered. The patient once again started taking chitosan and again had a significant increase in INR. The INR stabilized again once chitosan was discontinued. Researchers theorize that this interaction might occur because chitosan decreases absorption of fat-soluble vitamins, including vitamin K, which could increase the anticoagulant effect of warfarin.

Likelihood Possible Evidence D
Chitosan full monograph & interactions
The maker

Brand information

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

tnvitamins

See all tnvitamins products
Name
Total Nutrition, Inc.
City
Farmingdale
State
NY
ZipCode
11735
Phone Number
800-645-4446
Web Address
tnvitamins.com
Pharmacist Counseling Corner

Chitosan 400 mg by tnvitamins: Common Questions

Does Chitosan 400 mg by tnvitamins interact with any medications?
Yes. Based on its ingredients, Chitosan 400 mg has a known interaction with 3 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Chitosan 400 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this if I'm allergic to shellfish?
No. Chitosan is made from shellfish shells, so a shellfish allergy is a real concern. Don't take this product if you have that allergy.
What are the most common side effects?
The most common are constipation, diarrhea, bloating, stomach discomfort, and nausea. A dry throat and fatty stools have also been reported. Most people tolerate it well in the short term, but talk to your pharmacist if side effects bother you.
Is this safe to take during pregnancy or while breastfeeding?
No. There isn't enough safety data, and the information advises against use in both pregnancy and while breastfeeding. Discuss this with your doctor or pharmacist if you're in either situation.
Does chitosan actually help with weight loss?
The evidence rates it as possibly effective for obesity, meaning there's some support for it but it's not definitive. Talk with your doctor about whether it makes sense as part of your plan.

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

Not sure if Chitosan 400 mg 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.

Chitosan 400 mg label
Go deeper

The Full Monographs Behind Chitosan 400 mg’s Ingredients

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

Herb & supplement monograph

Chitosan

Interacts with 3 drugs

Chitosan is a fiber-like substance made from the shells of shrimp, crabs, and other shellfish, often marketed for weight loss and cholesterol. The evidence for these benefits is weak, and an...

Read the full Chitosan monograph →
Sources

Sources & How We Checked

Chitosan 400 mg'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 17 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.

Chitosan 17 references
  1. Jing SB, Li L, Ji D, et al. Effect of chitosan on renal function in patients with chronic renal failure. J Pharm Pharmacol 1997;49:721-3. PubMed
  2. Pittler MH, Abbot NC, Harkness EF, Ernst E. Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr 1999;53:379-81. PubMed
  3. Ho SC, Tai ES, Eng PH, et al. In the absence of dietary surveillance, chitosan does not reduce plasma lipids or obesity in hypercholesterolaemic obese Asian subjects. Singapore Med J 2001;42:6-10.
  4. Bokura H, Kobayashi S. Chitosan decreases total cholesterol in women: a randomized, double-blind, placebo-controlled trial. Eur J Clin Nutr 2003;57:721-5. PubMed
  5. Mhurchu CN, Poppitt SD, McGill AT, et al. The effect of the dietary supplement, Chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults. Int J Obes Relat Metab Disord 2004;28:1149-56. PubMed
  6. Huang SS, Sung SH, Chiang CE. Chitosan potentiation of warfarin effect. Ann Pharmacother 2007;41:1912-4. PubMed
  7. Tsai, G. J. and Su, W. H. Antibacterial activity of shrimp chitosan against Escherichia coli. J Food Prot. 1999;62(3):239-243. PubMed
  8. Wuolijoki, E., Hirvela, T., and Ylitalo, P. Decrease in serum LDL cholesterol with microcrystalline chitosan. Methods Find.Exp Clin Pharmacol. 1999;21(5):357-361. PubMed
  9. Nelson, J. L., Alexander, J. W., Gianotti, L., Chalk, C. L., and Pyles, T. Influence of dietary fiber on microbial growth in vitro and bacterial translocation after burn injury in mice. Nutrition 1994;10(1):32-36.
  10. Schiller RN, Barrager E, Schauss EA, and et al. A randomized, double-blind, placebo-controlled study examining the effects of a rapidly soluble chitosan dietary supplement on weight loss and body composition in overweight and mildly obese individuals. J
  11. Koide, S. S. Chitin-chitosan: properties, benefits and risks. Nutrition Research 1998;8(6):1091-1101. DOI
  12. Maezaki Y, Tsuji K, Nakawa, and et al. Hypocholesterolaemic effect of chitosan in adult males. Biosc Biochem Biotech 1993;57:1439-1444.
  13. Kubbinga M, Nguyen MA, Staubach P, et al. The influence of chitosan on the oral bioavailability of acyclovir-a comparative bioavailability study in humans. Pharm Res 2015;32(7):2241-9. PubMed
  14. Jull AB, Ni Mhurchu C, Bennett DA, et al. Chitosan for overweight or obesity. Cochrane Database Syst Rev 2008;(3):CD003892. PubMed
  15. Schmidl D, Werkmeister R, Kaya S, et al. A Controlled, Randomized Double-Blind Study to Evaluate the Safety and Efficacy of Chitosan-N-Acetylcysteine for the Treatment of Dry Eye Syndrome. J Ocul Pharmacol Ther. 2017;33(5):375-382.
  16. Moraru C, Mincea MM, Frandes M, Timar B, Ostafe V. A meta-analysis on randomised controlled clinical trials evaluating the effect of the dietary supplement chitosan on weight loss, lipid parameters and blood pressure. Medicina (Kaunas). 2018;54(6):109. PubMed
  17. García MA, Hensler G, Al-Gousous J, Pielenhofer J, Wagner M, Lennernäs H, Langguth P. Novel food drug interaction mechanism involving acyclovir, chitosan and endogenous mucus. Drug Metab Pharmacokinet. 2023;49:100491. PubMed

See these in context on the Chitosan monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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