Drug & supplement interaction

Glucomannan + Risedronate

Risedronate brand name: Actonel DR.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Glucomannan has a moderate interaction with Risedronate. Theoretically, glucomannan may decrease absorption of drugs taken orally.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceB
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Glucomannan and Risedronate

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ORAL DRUGS

Why this applies to Risedronate

Risedronate falls under ORAL DRUGS — the group Glucomannan interacts with.

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.
Severity Moderate Likelihood Probable Evidence B

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing about risedronate: your body already absorbs very little of it, and it's notoriously picky. That's why it has to be taken on an empty stomach first thing in the morning with plain water, and why even coffee, juice, or food can block it. Glucomannan is a thick, gel-forming fiber, so taking the two close together could trap the risedronate and lower how much gets into your system.

If less is absorbed, the medicine may simply not protect your bones as well, which defeats the purpose of taking it. This concern is mostly theoretical for risedronate specifically, but given how easily this drug is blocked, I'd keep them well apart. Take your risedronate as directed, then space the glucomannan hours later, and check the timing with your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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
  2. 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

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Glucomannan Also Interacts With Other Medications

Glucomannan has 2,021 moderate known drug interactions in our database — the Risedronate one above is one of them. If you take anything else, check it against the full list below.

Moderate 2,021 No known interaction 809 (incl. Risedronate)
Taking anything else?

Check Another of Your Medications Against Glucomannan

Covers the 2,830 medications we’ve checked against Glucomannan. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Risedronate

This page covers Glucomannan only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Risedronate page lists 23 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Calcium (moderate), Coffee Charcoal (moderate), Dolomite (moderate) and European Mandrake (moderate).

By severity: 1 major · 13 moderate · 9 minor.

From our pharmacist’s overview on the Risedronate page

“Risedronate (Actonel DR) is an osteoporosis medicine with an Achilles heel, poor absorption. Only a small fraction of each dose ever reaches the bone, and the 23 supplements on this page deserve genuine wariness because nearly all of them attack that weak point by binding or blunting the drug in the gut.”

Reviewed by 2 · Jul 18, 2026

Open the Risedronate interaction page

One more smart check

Taking Glucomannan as Part of a Dietary Supplement Product? Check It for Interactions

We hold 467 real supplement products containing Glucomannan, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Glucomannan. Your product may carry other ingredients that interact with Risedronate too, on top of Glucomannan — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Glucomannan and Risedronate Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Glucomannan
Top 25%

#269 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Risedronate
Steady interest

#1,611 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Glucomannan

What is Glucomannan?

Glucomannan
  • Weight loss and appetite control
  • Constipation
  • High cholesterol
  • Blood sugar support
  • Digestive health

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 generally well tolerated when taken with plenty of water, but it must be taken carefully because it can swell and cause choking or blockage if not swallowed properly. Talk with your pharmacist or doctor before starting it, especially if you have a health condition or take medicines.

Read the full Glucomannan monograph & all interactions
Medication

About Risedronate

What Is Risedronate Used For?

Brand name: Actonel DR

Risedronate sodium tablets are used to treat and prevent osteoporosis in postmenopausal women, treat osteoporosis in men to increase bone mass, and treat and prevent osteoporosis caused by long-term steroid (glucocorticoid) use in both men and women. They are also used to treat Paget's disease of bone — a condition where bones break down and rebuild abnormally, becoming enlarged and weakened.

Risedronate sodium delayed-release tablets (brands Atelvia and Risedronate Sodium delayed-release) are approved specifically for the treatment of postmenopausal osteoporosis only — not for the other uses listed above.

See full Risedronate drug information
Keep checking

Other Drugs & Glucomannan

Browse every other medication we’ve checked against Glucomannan — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
2,021Moderate
0Minor
808No known interaction
2,021 Moderate 808 No interaction
Moderate

2,021 interactions

Showing 60 of 2,021 moderate interactions — see all 2,021 on the Glucomannan page.

No interaction 808 drugs checked — show the list

We also checked Glucomannan against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Glucomannan list.

See the full Glucomannan interactions page
See every supplement checked against Risedronate, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

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

Keep exploring
Glucomannan monograph › Uses, safety, and every drug interaction in one place Risedronate supplement interactions › Every supplement checked against Risedronate, ranked by severity Risedronate drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Glucomannan and Risedronate Together: Common Questions

Can you take Glucomannan with Risedronate?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Glucomannan and Risedronate interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Risedronate and Glucomannan?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.