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Dietary supplement

Chitosan Ingredients & Drug Interactions

by BulkSupplements.com

Chitosan label
See full label image
Powder Category: Fiber And Other Nutrients
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Chitosan 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 is a dietary supplement by BulkSupplements.com 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 by BulkSupplements.com

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

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HelloPharmacist Scorecard of Chitosan by BulkSupplements.com

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 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 fiber derived from shellfish shells. Chitosan is thought to work partly by binding to fats and cholesterol in your digestive tract, which may affect how your body absorbs certain nutrients — and, as noted above, certain medications.

Does it work?

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

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

Moderate

Some clinical evidence supports Chitosan for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: Hypertension — rated "Possibly Effective" (Natural Medicines).
  • On file: Obesity — rated "Possibly Effective" (Natural Medicines).
  • On file: Postoperative recovery — rated "Possibly Effective" (Natural Medicines).

Chitosan has possibly effective evidence for obesity and postoperative recovery (healing after surgery) and possibly effective evidence for high blood pressure. For Crohn disease and dry eye, the evidence isn't established in the data we hold.

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 short-term, though quality evidence is limited. Common side effects taken by mouth include constipation, diarrhea, gas, belly discomfort, nausea, and throat dryness.

Some people have reported excessive fat in the stool (steatorrhea). Because chitosan comes from shellfish, it's a concern if you have a shellfish allergy.

Do not use chitosan during pregnancy or while breastfeeding — there isn't enough safety data to know either way, and the labeling advises against it. Talk with your doctor or pharmacist before use 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 taking this product, double-check with your pharmacist if you take warfarin (a blood thinner) or acyclovir (an antiviral). Warfarin users face a moderate risk of increased bleeding; acyclovir users face a moderate risk of reduced drug absorption.

If you take any other medications, use the search tool below to be sure.

Check your own medication Run your meds through the checker above

The bottom line

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

Chitosan may be worth considering if you're interested in possibly helping with weight, blood pressure, or recovery from surgery — but only if you don't take warfarin or acyclovir. If you take any prescription medication at all, check it against the tool on this page first.

A shellfish allergy is a deal-breaker, and don't use it in pregnancy or while breastfeeding.

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 May 23, 2024.

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, straight from the product label.

Brand BulkSupplements.com
Barcode (UPC) X0019NN6VD
Net contents 100 Gram(s); 3.5 Ounce(s)
Market status On market
Date entered into DSLD May 23, 2024
DSLD ID 312689
Product type Fiber And Other Nutrients
Supplement form Powder
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), 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 by BulkSupplements.com, 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:
1000 mg
Maximum serving Sizes:
1000 mg
Servings per container
100
UPC/BARCODE
X0019NN6VD
IngredientAmount% DV
Chitosan1000 mg--

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.
Brand IP Statement(s)

BulkSupplements.com Clean & pure bulk supplements

Precautions

Allergen Information: Shellfish

Always consult a physician before taking any dietary supplement.

Keep out of reach of children.

Formulation

Color may vary

Free Of: Added sugar, soy, dairy, yeast, gluten, additives

FDA Disclaimer Statement

Warning: This product is not intended to diagnose, treat, cure, or prevent any disease.

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement, take 1000 mg (about 1/3 tsp) once or twice daily, or as directed by a physician.

Storage

Store in a dry, cool place Contents are sold by weight, not volume. Settling may occur.

General Statements

New Use an accurate milligram scale.

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

See for yourself

Chitosan by BulkSupplements.com label

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

Chitosan 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 by BulkSupplements.com

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

Serving size1000 mg Dosage formPowder Servings per container100 Amounts shown are per serving.

Chitosan

Interacts with
3 drugs
1000 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
Interaction report

Chitosan by BulkSupplements.com Drug Interactions

Want to check YOUR meds against Chitosan?

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 interact with 3 drugs. Click any drug to see the details.

1 of the 1 ingredient in Chitosan 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 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, from the product label.

BulkSupplements.com

See all BulkSupplements.com products
Name
BulkSupplements.com
Street Address
7511 Eastgate Rd
City
Henderson
State
NV
ZipCode
89011
Web Address
BulkSupplements.com
Pharmacist Counseling Corner

Chitosan by BulkSupplements.com: Common Questions

Does Chitosan by BulkSupplements.com interact with any medications?
Yes. Based on its ingredients, Chitosan 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 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.
I'm allergic to shellfish. Can I take this?
No — chitosan is made from shellfish shells, so it's a concern for shellfish allergies. Skip this product and talk with your pharmacist about alternatives.
What's chitosan actually made of?
Chitosan is a fiber extracted from shellfish shells (usually shrimp or crab). Your body can't digest it, so it passes through your gut mostly intact — and along the way, it can bind to fats and cholesterol.
Will this help me lose weight?
The evidence suggests it may help — it's rated possibly effective for obesity. But it's not a guaranteed fix, and it works best alongside diet and exercise. Talk with your doctor about whether it's right for you.
What side effects should I expect?
Most common are constipation, diarrhea, gas, stomach discomfort, and nausea. Some people also report throat dryness or excessive fat in the stool. Most of these are mild and short-term, but let your pharmacist know if they don't settle down.
Can I take this while pregnant or breastfeeding?
No — there isn't enough safety data to know if it's safe, and the labeling advises against both pregnancy and breastfeeding. Talk with your doctor before use if you're pregnant, planning to become pregnant, or nursing.
How does this interact with my medications?
Chitosan can bind to certain drugs and reduce how well your body absorbs them — notably acyclovir for herpes, which may make it less effective. It may also increase bleeding risk with warfarin. Use the search tool on this page to check your exact medications.

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.

Chitosan label
Go deeper

The Full Monographs Behind Chitosan’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'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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