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Dietary supplement

Glucomannan 665 mg Ingredients & Drug Interactions

by Swanson

Glucomannan 665 mg label
See full label image
Capsule Category: Fiber And Other Nutrients
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 Glucomannan 665 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

Glucomannan 665 mg is a dietary supplement by Swanson with 1 active ingredient. Its ingredients are commonly taken for weight loss and appetite control, constipation, high cholesterol.Based on those ingredients, 2,022 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Glucomannan. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Glucomannan 665 mg by Swanson

Ask about any prescription or over-the-counter medication and we check it for interactions with Glucomannan 665 mg by Swanson — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Glucomannan 665 mg by Swanson

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: glucomannan, a soluble fiber derived from the konjac plant root. It works by absorbing water in your digestive tract, forming a thick gel that can help bulk up stool and support bowel regularity.

The capsule also contains inactive ingredients — gelatin, rice flour, and magnesium stearate — which are fillers and binders that hold the supplement together.

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
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: Supports bowel regularity and healthy blood sugar balance.
  • We looked for evidence on: Constipation, Diabetes, Hyperlipidemia, Metabolic syndrome, Glucose control, Cholesterol management.
  • The strongest evidence on file: Glucomannan is rated "Possibly Effective" for Constipation (Natural Medicines).
  • Also on file: Glucomannan is rated "Possibly Effective" for Diabetes, Hyperlipidemia.
  • Also on file: Glucomannan is rated "Insufficient Reliable Evidence To Rate" for Metabolic syndrome.

Glucomannan is possibly effective for constipation, type 2 diabetes, and high cholesterol (hyperlipidemia), based on the evidence we have. For high blood pressure, there isn't enough reliable evidence to say one way or the other.

If you're using it for one of those conditions, talk with your doctor about whether it's the right choice for you alongside your other treatments.

The evidence, ingredient by ingredient Glucomannan

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.

Glucomannan is generally well tolerated when you take it with plenty of water or other liquid. The most common side effects are abdominal pain, bloating, constipation, diarrhea, gas, nausea, and vomiting — especially at doses above 3 grams daily.

Serious but rare risks include choking and blockage of your esophagus or intestines, particularly if you take it as a dry powder or don't drink enough liquid with it. There isn't enough reliable safety data to say whether it's okay during pregnancy or breastfeeding, so talk with your doctor or pharmacist before using it if you're pregnant or nursing.

Side effects, ingredient by ingredient Glucomannan

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 — Glucomannan.
  • The most serious interaction on file is rated Moderate.
  • For scale: 2,023 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, check any oral medications you're on — Glucomannan may reduce their absorption. This is a Moderate-severity concern.

Take your drugs at a different time than this supplement, several hours apart, to minimize the risk.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Glucomannan may help with constipation, blood sugar, and cholesterol — but it can lower how much of your other oral medications your body absorbs. Take it several hours apart from your prescription drugs, always with plenty of water, and check your exact medications with us before you start.

If you're pregnant, nursing, or have a history of bowel blockage, talk to your pharmacist first.

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 Glucomannan 665 mg, straight from the product label.

Brand Swanson
Barcode (UPC) 087614117430
Net contents 90 Capsule(s)
Market status On market
Date entered into DSLD May 23, 2024
DSLD ID 308584
Product type Fiber And Other Nutrients
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
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 Glucomannan 665 mg by Swanson, 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:
2 Capsule(s)
Servings per container
90
UPC/BARCODE
087614117430
IngredientAmount% DV
Glucomannan665 mg--

Other ingredients: Gelatin, Rice Flour, 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.
Formulation

Supports bowel regularity Assists with occasional constipation Supports healthy blood sugar balance

Digestive health

General Statements

Science-backed quality since 1969

Suggested/Recommended/Usage/Directions

Suggested use: As a dietary supplement, take one capsule with a full glass of water before each meal. For maximum benefit, take up to two capsules before each meal.

Precautions

Warning: For adults only. Keep out of reach of children.

Consult your physician before using this or any product if you are pregnant or nursing, taking medication or have a medical condition.

Do not use if seal is broken.

Storage

Store in a cool, dry place.

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.

Formula

Glucomannan 665 mg per capsule Konjac root

FDA Statement of Identity

Herbal Supplement

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

See for yourself

Glucomannan 665 mg by Swanson label

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

Glucomannan 665 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 Glucomannan 665 mg by Swanson

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

Serving size1 Capsule(s) Dosage formCapsule Servings per container90 Amounts shown are per serving.

Glucomannan

Interacts with
2,022 drugs
665 mg per serving Form: Amorphophallus konjac

Glucomannan is a soluble fiber from the konjac root that swells into a gel in your stomach, which may help with mild weight loss, constipation, and mo...

Glucomannan monograph & interactions

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

Interaction report

Glucomannan 665 mg by Swanson Drug Interactions

Want to check YOUR meds against Glucomannan 665 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
2,022Drugs
2,022 Moderate

Ingredients driving the most interactions

Glucomannan 2,022

Individual Drug Interactions

The ingredients in Glucomannan 665 mg interact with 2,022 drugs. Click any drug to see the details.

1 of the 1 ingredient in Glucomannan 665 mg interact with drugs. Each result below shows which ingredient is responsible. Glucomannan

Each ingredient & the kinds of drugs it affects

For each ingredient in Glucomannan 665 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.

Glucomannan1 drug type · 2,022 drugs

Oral Drugs

Theoretically, glucomannan may decrease absorption of drugs taken orally.
Due to its viscosity and bulking effects, there is concern that glucomannan can decrease the absorption of oral drugs. A small clinical study in healthy volunteers shows that taking glyburide 2.5 mg plus glucomannan 3.9 grams with breakfast reduces plasma levels of glyburide when compared with breakfast and glyburide alone. In addition, animal research demonstrates this effect on amoxicillin, but shows increased absorption of metronidazole. This mouse model also demonstrates that metronidazole elimination is prolonged, but amoxicillin elimination is enhanced by 38%; glucomannan may also affect the distribution of some drugs. To avoid changes in absorption, take glucomannan 30-60 minutes after taking oral drugs.

Likelihood Probable Evidence B
Glucomannan full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Glucomannan 665 mg, from the product label.

Swanson

See all Swanson products
Name
Swanson Health Products
City
Fargo
State
ND
ZipCode
58104
Phone Number
1-800-437-4148
Web Address
swanson.com
Pharmacist Counseling Corner

Glucomannan 665 mg by Swanson: Common Questions

Does Glucomannan 665 mg by Swanson interact with any medications?
Yes. Based on its ingredients, Glucomannan 665 mg has a known interaction with 2,022 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Glucomannan 665 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.
Will this help my constipation?
Glucomannan is possibly effective for constipation based on the evidence we have. It works by bulking up stool with water. Make sure you drink plenty of liquid when you take it, or it may have the opposite effect.
Can I take this if I'm on blood pressure or diabetes medication?
Glucomannan may lower how well your body absorbs oral medications, including diabetes drugs. We've seen this happen in studies. Take your prescriptions at a different time — ideally several hours apart — and talk to your pharmacist about the right timing for your specific drugs.
What are the side effects?
Most people get mild digestive side effects like bloating, gas, or diarrhea when they start. Serious but rare problems — choking or intestinal blockage — can happen if you don't drink enough water with it or take a dry powder instead of a capsule. Always use plenty of liquid.
Is it safe during pregnancy?
There isn't enough reliable safety data to know. Talk with your doctor or pharmacist before using glucomannan if you're pregnant.
Can I take it while breastfeeding?
Little is known about its safety while you're breastfeeding. Caution is advised. Check with your doctor or pharmacist before starting it.
How much should I take?
This product is 665 mg per capsule. Gastrointestinal side effects become more likely at doses over 3 grams daily. Start low and increase slowly while drinking plenty of water.

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

Not sure if Glucomannan 665 mg is safe with your meds?

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Ask a pharmacist

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.

Glucomannan 665 mg label
Go deeper

The Full Monographs Behind Glucomannan 665 mg’s Ingredients

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

Herb & supplement monograph

Glucomannan

Interacts with 2,022 drugs

Glucomannan is a soluble fiber from the konjac root that swells into a gel in your stomach, which may help with mild weight loss, constipation, and modestly lowering cholesterol. It is gener...

Read the full Glucomannan monograph →
Sources

Sources & How We Checked

Glucomannan 665 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 15 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.

Glucomannan 15 references
  1. Henry DA, Mitchell AS, Aylward J, et al. Glucomannan and risk of oesophageal obstruction. Br Med J 1986;292:591-2. PubMed
  2. Shima K, Tanaka A, Ikegami H, et al. Effect of dietary fiber, glucomannan, on absorption of sulfonylurea in man. Horm Metab Res 1983;15:1-3. PubMed
  3. Villaverde, A. F., Benlloch, S., Berenguer, M., Miguel, Rayon J., Pina, R., and Berenguer, J. Acute hepatitis of cholestatic type possibly associated with the use of glucomannan (amorphophalus konjac). J Hepatol. 2004;41(6):1061-1062. PubMed
  4. Yoshida, M., Vanstone, C. A., Parsons, W. D., Zawistowski, J., and Jones, P. J. Effect of plant sterols and glucomannan on lipids in individuals with and without type II diabetes. Eur.J Clin Nutr. 2006;60(4):529-537. PubMed
  5. Wood, R. J., Fernandez, M. L., Sharman, M. J., Silvestre, R., Greene, C. M., Zern, T. L., Shrestha, S., Judelson, D. A., Gomez, A. L., Kraemer, W. J., and Volek, J. S. Effects of a carbohydrate-restricted diet with and without supplemental soluble fiber
  6. Vanderbeek, P. B., Fasano, C., O'Malley, G., and Hornstein, J. Esophageal obstruction from a hygroscopic pharmacobezoar containing glucomannan. Clin Toxicol.(Phila) 2007;45(1):80-82. PubMed
  7. Bernstein, J. A., Crandall, M. S., and Floyd, R. Respiratory sensitization of a food manufacturing worker to konjac glucomannan. J Asthma 2007;44(8):675-680. PubMed
  8. Shichijo, K., Kobayashi, Y., Fueki, R., Shimoyama, K., and Masaya, M. [2 cases of konjac bronchial asthma found outside the "konnyaku" producing district]. Arerugi 1969;18(2):97-100.
  9. Carabin IG, Lyon MR, Wood S, et al. Supplementation of the diet with the functional fiber PolyGlycoplex is well tolerated by healthy subjects in a clinical trial. Nutr J 2009;8:9. PubMed
  10. Lyon MR, Reichert RG. The effect of a novel viscous polysaccharide along with lifestyle changes on short-term weight loss and associated risk factors in overweight and obese adults: an observational retrospective clinical program analysis. Altern Med Rev
  11. Lyon M, Wood S, Pelletier X, et al. Effects of a 3-month supplementation with a novel soluble highly viscous polysaccharide on anthropometry and blood lipids in nondieting overweight or obese adults. J Hum Nutr Diet 2011;24(4):351-9. PubMed
  12. Han Y, Zhang L, Liu XQ, Zhao ZJ, Lv LX. Effect of glucomannan on functional constipation in children: a systematic review and meta-analysis of randomised controlled trials. Asia Pac J Clin Nutr 2017;26(3):471-7.
  13. Health Canada Safety Alert. Health Canada Advises Canadians that natural health products containing glucomannan may cause serious choking if used with insufficient fluid. January 29, 2010. Alert # RA-110003825. https://healthycanadians.gc.ca/recall-alert-
  14. Mortensen A, Aguilar F, Crebelli, et al. EFSA Panel on Food Additives and Nutrient Sources added to Food. Re-evaluation of konjac gum (E 425 i) and konjac glucomannan (E425 ii) as food additives. EFSA Journal 2017;15(6):4864.
  15. Zhang Y, Aldamarany WAS, Song G, et al. Influence of konjac glucomannan and its derivatives on the oral pharmacokinetics of antimicrobial agent in antibiotics cocktails: Keep vigilant on dietary fiber supplement. Int J Biol Macromol 2023;251:126306. PubMed

See these in context on the Glucomannan 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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