Drug & supplement interaction

Blond Psyllium + Metformin Hydrochloride

Metformin Hydrochloride brand name: Riomet ER.

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

Metformin Hydrochloride falls into 2 drug categories that Blond Psyllium can interact with; the most serious is rated moderate. Theoretically, blond psyllium might increase the therapeutic and adverse effects of metformin.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Blond Psyllium and Metformin Hydrochloride

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Blond Psyllium interacts with whole categories of medication. Metformin Hydrochloride falls into 2 of those categories, so it can interact with Blond Psyllium in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

METFORMIN (Glucophage)

1 of 2
Theoretically, blond psyllium might increase the therapeutic and adverse effects of metformin.
Concurrent use of blond psyllium with metformin slows and increases metformin absorption. To avoid changes in absorption, take psyllium 30-60 minutes after metformin.
Severity Moderate Likelihood Possible Evidence D

Interaction 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.

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

Here's the deal with pairing psyllium and your metformin. That thick gel psyllium forms in your gut can change how your metformin gets absorbed. The research we have is mostly lab-based and theoretical, so this isn't a guaranteed problem, but the thinking is that psyllium may slow down and slightly increase how much metformin your body takes in. In plain terms, your blood sugar lowering effect could be a touch stronger, and so could metformin's usual side effects like nausea, stomach upset, diarrhea, or that off feeling when sugar runs low.

An easy fix many people use is to take your metformin first, then take psyllium about 30 to 60 minutes later. Run this past your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Diez R, Garcia JJ, Diez MJ, Sierra M, Sahagun AM, Fernandez N. Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits. BMC Complement Altern Med. 2017 Jun 7;17(1):298. PubMed
Minor

ORAL DRUGS

2 of 2

Why this applies to Metformin Hydrochloride

Metformin Hydrochloride falls under ORAL DRUGS — the group Blond Psyllium interacts with.

Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Psyllium seems to have variable effects on drug absorption. To avoid changes in absorption, take psyllium 30-60 minutes after oral medications. Animal research shows that blond psyllium delays and increases the absorption of metformin and ethinyl estradiol. Conversely, case reports and animal research suggest that blond psyllium might reduce absorption of lithium, digoxin, olanzapine, and carbamazepine. Finally, some pharmacokinetic studies show that psyllium does not affect the absorption of levothyroxine or warfarin.
Severity Minor Likelihood Possible Evidence B

Interaction 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.

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

Here's the simple version: blond psyllium is a thick, gel-forming fiber, and when you take it at the same time as your metformin, it can change how your body absorbs the pill. With metformin specifically, animal studies suggest psyllium may slow down absorption but also slightly increase the total amount that gets in. The practical effect tends to be small, and the evidence here is limited, so I wouldn't lose sleep over it.

To keep things steady, a good habit is to take your metformin first and then wait about 30 to 60 minutes before your psyllium. That way the fiber gel doesn't interfere with the pill. If you ever notice unusual changes, like more low blood sugar feelings, stomach upset, or your numbers running differently, check in with your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  4. Robinson DS, Benjamin DM, McCormack JJ. Interaction of warfarin and nonsystemic gastrointestinal drugs. Clin Pharmacol Ther 1971;12:491-5. PubMed
  5. Garcia JJ, Fernandez N, Diez MJ, et al. Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol. Contraception 2000;62:253-7. PubMed
  6. Semen plantaginis in: WHO Monographs on Selected Medicinal Plants, volume 1. World Health Organization, Geneva, 1999. Available at http://apps.who.int/medicinedocs/en/d/Js2200e/. Accessed November 26, 1026.
  7. Diez R, Garcia JJ, Diez MJ, Sierra M, Sahagun AM, Fernandez N. Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits. BMC Complement Altern Med. 2017 Jun 7;17(1):298. PubMed
  8. Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid. 1998;8(8):667-71. PubMed
  9. Merrick C, Madden CA, Capurso NA. A Case of Blunted Orally Disintegrating Olanzapine Effect Due to Coadministered Psyllium. J Clin Psychiatry 2021;82(2):20cr13633. 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

Blond Psyllium Also Interacts With Other Medications

Blond Psyllium has 22 moderate, 2,002 minor known drug interactions in our database — the Metformin Hydrochloride one above is among them. If you take anything else, check it against the full list below.

Moderate 22 Minor 2,002 No known interaction 806 (incl. Metformin Hydrochloride)
Taking anything else?

Check Another of Your Medications Against Blond Psyllium

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

Everything else you take

See Every Supplement That Interacts With Metformin Hydrochloride

This page covers Blond Psyllium only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin Hydrochloride page lists 257 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Siberian Cocklebur (major), Acai (moderate), African Wild Potato (moderate) and Agaricus Mushroom (moderate).

By severity: 2 major · 217 moderate · 38 minor.

From our pharmacist’s overview on the Metformin Hydrochloride page

“Anyone taking metformin hydrochloride (Riomet ER) should treat this list with genuine care, because two of its 257 entries are rated major. Siberian cocklebur has caused severe hypoglycemia in people and should not be combined with metformin at all, and activated charcoal can adsorb the drug in the gut so less reaches your blood.”

Reviewed by 2 · Jul 18, 2026

Open the Metformin Hydrochloride interaction page

One more smart check

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

We hold 97 real supplement products containing Blond Psyllium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Blond Psyllium. Your product may carry other ingredients that interact with Metformin Hydrochloride too, on top of Blond Psyllium — 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 Blond Psyllium and Metformin Hydrochloride 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 Blond Psyllium
Top half

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

29 days ago today
Medication Metformin Hydrochloride
Top 10%

#147 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 Blond Psyllium

What is Blond Psyllium?

Blond Psyllium
  • Constipation relief
  • Diarrhea and loose stools
  • High cholesterol
  • Digestive/gut health
  • Blood sugar support
  • Feeling fuller for weight management

Blond psyllium is a soluble fiber from the seed husks of Plantago ovata, and it is one of the better-studied fiber supplements. It can help with both constipation and diarrhea and may modestly lower cholesterol and blood sugar. It is generally well tolerated when taken with plenty of water, but always start low and check with your pharmacist or doctor first.

Read the full Blond Psyllium monograph & all interactions
Keep checking

Other Drugs & Blond Psyllium

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

0Major
22Moderate
2,002Minor
805No known interaction
22 Moderate 2,002 Minor 805 No interaction
Moderate

22 interactions

Minor

2,002 interactions

Showing 60 of 2,002 minor interactions — see all 2,002 on the Blond Psyllium page.

No interaction 805 drugs checked — show the list

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

Showing the 60 most looked-up of 805 medications checked with no known interaction — see the full Blond Psyllium list.

See the full Blond Psyllium interactions page
See every supplement checked against Metformin Hydrochloride, 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
Blond Psyllium monograph › Uses, safety, and every drug interaction in one place Metformin Hydrochloride supplement interactions › Every supplement checked against Metformin Hydrochloride, ranked by severity 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 Blond Psyllium and Metformin Hydrochloride Together: Common Questions

Can you take Blond Psyllium with Metformin Hydrochloride?
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.
Why are there 2 interactions listed for Blond Psyllium and Metformin Hydrochloride?
Metformin Hydrochloride belongs to more than one drug category, and Blond Psyllium interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Blond Psyllium and Metformin Hydrochloride 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 Metformin Hydrochloride and Blond Psyllium?

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.