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Dietary supplement

Glucomannan 500 mg Ingredients & Drug Interactions

by tnvitamins

Glucomannan 500 mg label
See full label image
Capsule Category: Fiber And Other 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 Glucomannan 500 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 500 mg is a dietary supplement by tnvitamins 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 powder. 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 500 mg by tnvitamins

Ask about any prescription or over-the-counter medication and we check it for interactions with Glucomannan 500 mg by tnvitamins — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Glucomannan 500 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 30, 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 powder, a soluble fiber derived from the konjac plant. The capsule also holds three inactive ingredients—gelatin, magnesium stearate, and silicon dioxide—which are fillers and binders that help form and protect the capsule.

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 Glucomannan's overall clinical evidence instead.

Moderate

Some clinical evidence supports Glucomannan 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: Constipation — rated "Possibly Effective" (Natural Medicines).
  • On file: Diabetes — rated "Possibly Effective" (Natural Medicines).
  • On file: Hyperlipidemia — rated "Possibly Effective" (Natural Medicines).

The evidence shows glucomannan is possibly effective for constipation, diabetes, and high cholesterol (hyperlipidemia). For high blood pressure, the data we hold isn't strong enough to rate it either way.

These ratings mean there's some clinical support, but the research isn't ironclad—talk with your doctor about whether it fits your situation.

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 drink plenty of water with it. The most common side effects are mild gastrointestinal ones: abdominal pain, bloating, gas, diarrhea, constipation, nausea, or vomiting—especially if you take more than 3 grams daily.

Rare but serious: choking and esophageal or gastrointestinal blockage can happen if you don't swallow it properly or if you take it as a dry powder without enough fluid. For pregnancy, there isn't enough reliable safety data—talk with your doctor before using it.

Safety while breastfeeding is also unclear, so caution is advised; check with your doctor or pharmacist before starting.

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 you take Glucomannan 500 mg, check with your doctor or pharmacist about any oral medications you're on. Because glucomannan can reduce how much of your drugs your body absorbs, timing matters—most oral medications need to be taken at least two hours apart from this supplement.

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.

Glucomannan may help with constipation, blood sugar control, or cholesterol if the research applies to you. The main catch is timing: you'll need to separate it from your medications by at least two hours so it doesn't interfere with absorption.

If you're pregnant or breastfeeding, don't use it without checking with your doctor first. Run your medications through the checker on this page before you start.

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 Glucomannan 500 mg, straight from the product label.

Brand tnvitamins
Barcode (UPC) 095234135000
Net contents 100 Capsule(s)
Market status On market
Date entered into DSLD Apr 23, 2020
DSLD ID 217907
Product type Fiber And Other Nutrients
Supplement form Capsule
Dietary claims / uses Nutrient, All Other
Intended target group(s) Adult (18 - 50 Years), 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 Glucomannan 500 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:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
100
UPC/BARCODE
095234135000
IngredientAmount% DV
Glucomannan powder500 mg--

Other ingredients: Gelatin, Magnesium Stearate, Silicon Dioxide

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

Natural konjac fiber

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Directions: As a dietary supplement, take one (1) capsule before a meal with 8 oz. of juice or water, or as directed by a health care professional.

Formulation

Free of: Corn, soy, yeast, wheat, milk, egg, artificial color, flavor, sweeteners & preservatives. Non-GMO

Precautions

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. Please consult your physician prior to beginning any exercise or weight loss program.

Keep out of reach of children.

Storage

Store in a cool, dry place.

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

Glucomannan 500 mg by tnvitamins label

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

Glucomannan 500 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 500 mg by tnvitamins

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 container100 Amounts shown are per serving.

Glucomannan powder

Interacts with
2,022 drugs
500 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 powder monograph & interactions

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

Interaction report

Glucomannan 500 mg by tnvitamins Drug Interactions

Want to check YOUR meds against Glucomannan 500 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 powder 2,022

Individual Drug Interactions

The ingredients in Glucomannan 500 mg interact with 2,022 drugs. Click any drug to see the details.

1 of the 1 ingredient in Glucomannan 500 mg interact with drugs. Each result below shows which ingredient is responsible. Glucomannan powder

Each ingredient & the kinds of drugs it affects

For each ingredient in Glucomannan 500 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.

Glucomannan powder1 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 powder full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Glucomannan 500 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

Glucomannan 500 mg by tnvitamins: Common Questions

Does Glucomannan 500 mg by tnvitamins interact with any medications?
Yes. Based on its ingredients, Glucomannan 500 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 500 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 glucomannan help my constipation?
The evidence shows it's possibly effective for constipation. That means there's some clinical support, but results vary. Talk with your doctor about whether it's a good fit for you, and make sure to drink plenty of water with it—that's key to how it works and to safety.
Can I take this with my diabetes medication?
Not at the same time. A clinical study showed glucomannan lowered blood levels of glyburide, a diabetes drug. Take your medication and this supplement at least two hours apart—before breakfast or well after dinner. Check with your doctor or pharmacist about the best timing for your specific medications.
What are the most common side effects?
Abdominal pain, bloating, gas, diarrhea, constipation, nausea, or vomiting—especially if you take more than 3 grams a day. Taking it with plenty of water and starting with a lower dose usually helps. If side effects don't improve, talk with your pharmacist.
Is it safe to take while pregnant?
There isn't enough reliable safety data. Don't use it during pregnancy without talking to your doctor first—they can weigh the pros and cons for your situation.
What's glucomannan, and what does it do?
It's a soluble fiber from the konjac plant that absorbs water and bulks up in your digestive system. The evidence shows it's possibly effective for constipation, diabetes, and high cholesterol. It works best when you drink plenty of water with it.
Can I choke on this?
Rare but real: choking and blockage in your esophagus or intestines can happen if you don't swallow it properly or if you take it dry without enough fluid. Swallow the capsule with a full glass of water, and don't take it as a dry powder.

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

Not sure if Glucomannan 500 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.

Glucomannan 500 mg label
Go deeper

The Full Monographs Behind Glucomannan 500 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 500 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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