Interactions on record — worth a quick check against your medications. Based on 4 of 5 ingredients. Check your meds →
Dietary supplement

Fiber Formula Ingredients & Drug Interactions

by Integrative Therapeutics

Fiber Formula label
See full label image
Capsule Category: Botanical With 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 Fiber Formula 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

Fiber Formula is a dietary supplement by Integrative Therapeutics with 5 active ingredients. Its ingredients are commonly taken for constipation, diarrhea, high cholesterol.Based on those ingredients, 2,031 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Dietary Fiber, Guar Gum, Psyllium. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Fiber Formula by Integrative Therapeutics

Ask about any prescription or over-the-counter medication and we check it for interactions with Fiber Formula by Integrative Therapeutics — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Fiber Formula by Integrative Therapeutics

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

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 1 of its 5 active ingredients.
  • “Proprietary Fiber Blend” is a proprietary blend — the label gives one combined amount (3.10 Gram(s)) without saying how much of each component you get.

Fiber Formula contains 6 active ingredients. Guar gum, psyllium (blond psyllium), and pectin are soluble fibers that dissolve in water and help thicken the intestinal contents.

Soluble fiber and insoluble fiber work together to add bulk and support digestive health. Oat bran contributes additional fiber, and the proprietary fiber blend rounds out the formulation with its own fiber sources.

The product also contains inactive ingredients — hydroxypropyl methylcellulose, cellulose, magnesium stearate, and silicon dioxide — which are fillers, binders, and capsule materials.

Does it work?

Strong 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
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: Digestive health and bowel regularity.
  • We looked for evidence on: Constipation, Diarrhea, Irritable bowel syndrome (IBS), Hemorrhoids, Hypercholesterolemia, Hyperlipidemia — and 4 related terms.
  • The strongest evidence on file: Black Psyllium is rated "Effective" for Constipation (Natural Medicines).
  • Also on file: Blond Psyllium is rated "Effective" for Constipation.
  • Also on file: Blond Psyllium is rated "Likely Effective" for Hyperlipidemia.

Psyllium has the strongest evidence in this formula: it's rated effective for constipation and likely effective for high cholesterol and heart disease risk. Guar gum is rated possibly effective for high blood pressure, high cholesterol, irritable bowel syndrome, and constipation.

Pectin is rated possibly effective for high cholesterol but has insufficient evidence for blood sugar control (prediabetes) and radiation exposure. We don't have effectiveness ratings on file for soluble fiber, insoluble fiber, oat bran, or the proprietary blend.

The evidence, ingredient by ingredient Black Psyllium Guar Gum Blond Psyllium Pectin

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 4 of the 4 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 4 of 4.
  • General safety write-ups exist for 4 of 4.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Psyllium is generally well tolerated when you drink plenty of water with it — the most common side effects are abdominal pain, constipation, diarrhea, gas, and nausea. Guar gum causes similar digestive effects (bloating, flatulence, loose stools) and is also generally well tolerated when you take it with adequate fluid.

Pectin tends to cause mild digestive upset like diarrhea, gas, and cramps. All three can rarely cause serious bowel or esophageal obstruction if taken without enough water — this is a real risk, so drink plenty.

A small number of people are allergic to psyllium or pectin, with symptoms ranging from sneezing and rash to wheezing and anaphylaxis; occupational exposure over time can trigger this sensitivity. For pregnancy, psyllium is rated likely safe.

Guar gum is rated possibly safe but hasn't been well studied in supplement doses, so check with your doctor. Pectin is rated likely safe for pregnancy and lactation.

Food amounts of all three are considered acceptable during pregnancy, but if you're pregnant or nursing and taking this as a supplement, talk with your doctor or pharmacist first.

Side effects, ingredient by ingredient Black Psyllium Guar Gum Blond Psyllium Pectin

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?
  • 4 of the 4 matched ingredients can interact with medications — Black Psyllium, Pectin, Blond Psyllium, Guar Gum.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: heart-rhythm medications; lithium.
  • For scale: 2,032 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 doctor or pharmacist if you take metformin, lithium, carbamazepine, olanzapine, penicillin or other antibiotics, lovastatin, tetracycline antibiotics, digoxin, or birth control pills — all of these have moderate or minor interactions with one or more ingredients in this formula. Separate doses by 30–60 minutes.

Altogether, these interactions span 2,032 individual medications.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with clinical evidence supporting its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

This formula is a solid choice for constipation and cholesterol support if your medications don't conflict with fiber's absorption effects. The biggest concern is timing: you must separate this product from metformin, lithium, carbamazepine, olanzapine, birth control, digoxin, penicillin, and other antibiotics by at least 30–60 minutes.

Take it with plenty of water to avoid blockage. Before you start, run your complete medication list through the interaction checker on this page, then confirm the timing with your doctor or pharmacist.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 4 of 5 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jun 16, 2022.

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 Fiber Formula, straight from the product label.

Brand Integrative Therapeutics
Barcode (UPC) 871791003255
Net contents 120 Veg Capsule(s)
Market status On market
Date entered into DSLD Jun 16, 2022
DSLD ID 269907
Product type Botanical With Nutrients
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, 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 Fiber Formula by Integrative Therapeutics, 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:
5 Capsule(s)
Maximum serving Sizes:
5 Capsule(s)
Servings per container
24
UPC/BARCODE
871791003255
IngredientAmount% DV
Calories5 Calorie(s)--
Dietary Fiber3 Gram(s)11%
Soluble Fiber1 Gram(s)--
Insoluble Fiber2 Gram(s)--
Total Carbohydrate3 Gram(s)1%
Guar Gum0 NP--
Oat (Avena sativa) Bran0 NP--
Proprietary Fiber Blend3.1 Gram(s)--
Psyllium0 NP--
Pectin0 NP--

Other ingredients: Hydroxypropyl Methylcellulose, Cellulose, 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.
Precautions

If you experience chest pain, vomiting, or difficulty swallowing or breathing after taking this product, seek immediate medical attention.

If you are pregnant, nursing, or taking prescription drugs, consult a healthcare professional before use.

Keep out of reach of children.

Safety sealed with printed inner seal. Do not use if seal is broken or missing.

Warning: Do not take this products if you have difficulty swallowing. Take this product with at least a full glass of liquid (8 oz). Taking this product without adequate fluid may cause it to swell and block your throat or esophagus and may cause choking.

General Statements

For more information, please visit integrativepro.com.

Formulation

Contains no salt, soy, dairy products, ingredients of animal origin, or artificial colors, flavors, or preservatives.

Contains no salt, soy, dairy products, ingredients of animal origin, or artificial colors, flavors, or preservatives.

Brand IP Statement(s)

Copyright 2019 Integrative Therapeutics, LLC

FDA Disclaimer Statement

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Recommendation: Take 5 capsules daily with at least 8 oz of liquid. If desired, may be taken as 2 capsules in the morning, and 3 capsules at night, with at least 8 oz of liquid, or as recommended by a healthcare professional.

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

See for yourself

Fiber Formula by Integrative Therapeutics label

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

Fiber Formula 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 Fiber Formula by Integrative Therapeutics

These are the 5 active ingredients this product is made of. Select any to open its full monograph.

Serving size5 Capsule(s) Dosage formCapsule Servings per container24 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Dietary Fiber

Interacts with
2,025 drugs
3 Gram(s) per serving

Black psyllium is a soluble-fiber supplement made from the seeds of a Plantago plant, used mostly to ease constipation and support digestive health. I...

Dietary Fiber monograph & interactions
  • › Soluble Fiber
  • › Insoluble Fiber

Proprietary Fiber Blend

3.1 Gram(s) per serving

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

Interaction report

Fiber Formula by Integrative Therapeutics Drug Interactions

Want to check YOUR meds against Fiber Formula?

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
2,031Drugs
2,031 Moderate

Ingredients driving the most interactions

Dietary Fiber 2,025
Guar Gum 2,025
Psyllium 2,025
Pectin 23

Individual Drug Interactions

The ingredients in Fiber Formula interact with 2,031 drugs. Click any drug to see the details.

4 of the 5 ingredients in Fiber Formula interact with drugs. Each result below shows which ingredient is responsible. Dietary Fiber Guar Gum Psyllium Pectin

Each ingredient & the kinds of drugs it affects

For each ingredient in Fiber Formula with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Dietary Fiber7 drug types · 2,025 drugs

Carbamazepine (Tegretol)

Theoretically, black psyllium might reduce the effects of carbamazepine and increase the risk for convulsions.
Theoretically, black psyllium might reduce carbamazepine absorption. A preliminary study using blond psyllium reported decreased carbamazepine bioavailability due to binding of the drug to psyllium, as well as reduction of available fluid in the gut for dissolution of the drug. This interaction may also occur with black psyllium.

Likelihood Probable Evidence D
Lithium

Theoretically, taking black psyllium at the same time as lithium might reduce lithium absorption.
The fiber in black psyllium might reduce lithium absorption and plasma levels. Some case reports describe a reduction in plasma lithium levels with concomitant administration of blond psyllium. This was reversed when psyllium was stopped. This interaction may also occur with black psyllium.

Likelihood Probable Evidence D
Metformin (Glucophage)

Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Animal research shows that concurrent consumption of blond psyllium with metformin slows and increases the absorption of metformin. This interaction may also occur with black psyllium. To avoid changes in absorption, take psyllium 30-60 minutes after metformin.

Likelihood Possible Evidence D
Olanzapine (Zyprexa)

Theoretically, taking black psyllium at the same time as olanzapine might reduce olanzapine absorption.
The fiber in black psyllium might decrease the absorption of olanzapine. A single case report describes a reduction in the effectiveness of olanzapine when it was concomitantly administered with an unspecified type of psyllium 3 grams orally twice daily. This effect was reversed when psyllium was stopped.

Likelihood Possible Evidence D
Digoxin (Lanoxin)

Theoretically, taking black psyllium at the same time as digoxin might reduce digoxin absorption and decrease digoxin levels.
Psyllium might bind digoxin in the gut. However, some clinical evidence suggests that psyllium does not impact digoxin absorption.

Likelihood Unlikely Evidence B
Ethinyl Estradiol

Theoretically, taking black psyllium at the same time as ethinyl estradiol might alter levels of estradiol.
Concurrent use of blond psyllium with ethinyl estradiol results in a slight increase in the extent of ethinyl estradiol absorption and a slower rate of absorption. This is unlikely to be clinically significant.

Likelihood Unlikely Evidence D
Oral Drugs

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. 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. Although many of these studies evaluated blond psyllium, the fiber content in black psyllium may have similar effects.

Likelihood Possible Evidence B
Dietary Fiber full monograph & interactions

Guar Gum5 drug types · 2,025 drugs

Ethinyl Estradiol

Theoretically, guar gum might reduce the absorption of ethinyl estradiol, potentially decreasing its effectiveness.
Animal research shows that taking guar gum with ethinyl estradiol decreases ethinyl estradiol absorption. However, this effect has not been reported in humans.

Likelihood Possible Evidence D
Metformin (Glucophage)

Guar gum might reduce the absorption of metformin, potentially decreasing its effectiveness.
A small study in healthy volunteers shows that guar gum reduces the absorption rate of metformin.

Likelihood Probable Evidence B
Oral Drugs

Guar gum might reduce the absorption of some oral drugs, potentially decreasing their effectiveness.
Clinical research shows that guar gum reduces or slows absorption of medications such as penicillin and metformin. To avoid changes in absorption, take guar gum 30-60 minutes after oral medications.

Likelihood Possible Evidence B
Penicillin

Guar gum might reduce the absorption of penicillin, potentially decreasing its effectiveness.
A small clinical study in healthy volunteers shows that taking guar gum with penicillin results in decreased penicillin absorption and reduced penicillin levels.

Likelihood Probable Evidence B
Digoxin (Lanoxin)

Guar gum might slow digoxin absorption, but it does not seem to impact how much digoxin is absorbed overall.
Two small studies in healthy volunteers show no change in the overall extent of digoxin absorption, although early absorption was slowed, when taken with guar gum.

Likelihood Possible Evidence B
Guar Gum full monograph & interactions

Psyllium7 drug types · 2,025 drugs

Carbamazepine (Tegretol)

Theoretically, blond psyllium might reduce the effects of carbamazepine and increase the risk for convulsions.
Blond psyllium might reduce carbamazepine absorption and serum levels. A preliminary study using blond psyllium reported decreased carbamazepine bioavailability due to binding of the drug to psyllium, as well as reduction of available fluid in the gut for dissolution of the drug.

Likelihood Probable Evidence D
Lithium

Theoretically, taking blond psyllium at the same time as lithium might reduce lithium absorption.
The fiber in blond psyllium might decrease the absorption of lithium. Some case reports describe a reduction in plasma lithium levels with concomitant administration of blond psyllium. This was reversed when psyllium was stopped.

Likelihood Probable Evidence D
Metformin (Glucophage)

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.

Likelihood Possible Evidence D
Olanzapine (Zyprexa)

Theoretically, taking blond psyllium at the same time as olanzapine might reduce olanzapine absorption.
The fiber in blond psyllium might decrease the absorption of olanzapine. A single case report describes a reduction in the effectiveness of olanzapine when it was taken concomitantly with an unspecified type of psyllium 3 grams orally twice daily. This effect was reversed when psyllium was stopped.

Likelihood Possible Evidence D
Digoxin (Lanoxin)

Theoretically, taking blond psyllium at the same time as digoxin might reduce digoxin absorption.
Psyllium might bind digoxin in the gut. However, some clinical evidence suggests that psyllium does not impact digoxin absorption.

Likelihood Unlikely Evidence B
Ethinyl Estradiol

Theoretically, taking blond psyllium at the same time as ethinyl estradiol might alter levels of estradiol.
Concurrent use of blond psyllium with ethinyl estradiol results in a slight increase in the extent of ethinyl estradiol absorption and a slower rate of absorption. However, this is unlikely to be clinically significant.

Likelihood Unlikely Evidence D
Oral Drugs

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.

Likelihood Possible Evidence B
Psyllium full monograph & interactions

Pectin3 drug types · 23 drugs

Digoxin (Lanoxin)

Theoretically, pectin might reduce the absorption of digoxin, potentially decreasing its effectiveness.
A small clinical study shows that taking digoxin with a kaolin-pectin suspension reduces the absorption of digoxin by about 62%. It is unclear if these effects are due to pectin, kaolin, or the combination.

Likelihood Possible Evidence B
Lovastatin (Mevacor)

Theoretically, pectin might reduce the absorption of lovastatin, potentially decreasing its effectiveness.
Case reports suggest that concomitant use of pectin and lovastatin might reduce the cholesterol-lowering effect of lovastatin, possibly due to reduced intestinal absorption of lovastatin.

Likelihood Possible Evidence D
Tetracycline Antibiotics

Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
A small clinical study shows that taking tetracycline with bismuth subsalicylate in a kaolin-pectin suspension reduces the absorption of tetracycline by about 34%. It is unclear if these effects are due to pectin, kaolin, bismuth subsalicylate, or the combination.

Likelihood Possible Evidence B
Pectin full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Fiber Formula, from the product label.

Integrative Therapeutics

See all Integrative Therapeutics products
Name
Integrative Therapeutics, LLC
City
Green Bay
State
WI
ZipCode
54311
Phone Number
800.931.1709
Web Address
integrativepro.com
Pharmacist Counseling Corner

Fiber Formula by Integrative Therapeutics: Common Questions

Does Fiber Formula by Integrative Therapeutics interact with any medications?
Yes. Based on its ingredients, Fiber Formula has a known interaction with 2,031 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Fiber Formula contains 5 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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.
Do I really need to space out this product and my other medications?
Yes. Fiber can bind medications in your stomach and reduce how much your body absorbs them, making them less effective. The safest approach is to take this product at least 30–60 minutes after your medications. If you're on metformin, lithium, digoxin, or an antibiotic, this timing is especially important.
Can I take this product during pregnancy?
Psyllium and pectin are rated likely safe in pregnancy, and guar gum is possibly safe, but supplement doses haven't been thoroughly studied. Food amounts of fiber are fine, but talk with your doctor before starting this supplement if you're pregnant to make sure it's right for you.
What are the most common side effects I should expect?
Most people experience some digestive discomfort — bloating, gas, abdominal pain, or loose stools — especially when they first start. These usually improve if you drink plenty of water and start with a smaller dose. If you have severe pain or the side effects don't ease up, stop and check with your doctor.
Can this product help my cholesterol?
Yes. Psyllium is likely effective for high cholesterol and heart disease risk, and both guar gum and pectin are possibly effective for cholesterol. The stronger evidence is behind psyllium.
Is this safe to use if I have irritable bowel syndrome?
Guar gum is rated possibly effective for IBS. However, fiber can sometimes make bloating and gas worse in people with IBS, so check with your doctor before starting, and consider beginning with a very small dose to see how you tolerate it.
What happens if I don't drink enough water with this?
Fiber needs water to move through your digestive system safely. Without enough fluid, it can cause a blockage in your esophagus or small intestine — a serious, rare complication. Always take this product with a full glass of water and drink plenty of fluids throughout the day.

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.

Fiber Formula label
Go deeper

The Full Monographs Behind Fiber Formula’s Ingredients

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

Herb & supplement monograph

Black Psyllium

Interacts with 2,025 drugs

Black psyllium is a soluble-fiber supplement made from the seeds of a Plantago plant, used mostly to ease constipation and support digestive health. It is best known and most studied for rel...

Read the full Black Psyllium monograph → Herb & supplement monograph

Guar Gum

Interacts with 2,025 drugs

Guar gum is a soluble, gel-forming fiber from the guar bean that may modestly help with cholesterol, blood sugar, and bowel regularity. It is generally safe in food amounts, but concentrated...

Read the full Guar Gum monograph → Herb & supplement monograph

Blond Psyllium

Interacts with 2,025 drugs

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 modest...

Read the full Blond Psyllium monograph → Herb & supplement monograph

Pectin

Interacts with 23 drugs

Pectin is a natural soluble fiber found in fruits like apples and citrus, and it is widely used in foods and as a fiber supplement. It may modestly help with cholesterol, blood sugar, and di...

Read the full Pectin monograph →
Sources

Sources & How We Checked

Fiber Formula'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 83 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.

Black Psyllium 18 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. Etman M. Effect of a bulk forming laxative on the bioavailablility of carbamazepine in man. Drug Dev Ind Pharm 1995;21:1901-6.
  5. Perlman BB. Interaction between lithium salts and ispaghula husk. Lancet 1990;335:416.
  6. Vaswani SK, Hamilton RG, Valentine MD, Adkinson NF. Psyllium laxative-induced anaphylaxis, asthma, and rhinitis. Allergy 1996;51:266-8. PubMed
  7. Lantner RR, Espiritu BR, Zumerchik P, Tobin MC. Anaphylaxis following ingestion of a psyllium-containing cereal. JAMA 1990;264:2534-6. DOI
  8. Kaplan MJ. Anaphylactic reaction to "Heartwise." N Engl J Med 1990;323:1072-3. DOI
  9. Nordstrom M, Melander A, Robertsson E, Steen B. Influence of wheat bran and of a bulk-forming ispaghula cathartic on the bioavailability of digoxin in geriatric in-patients. Drug Nutr Interact 1987;5:67-9..
  10. Robinson DS, Benjamin DM, McCormack JJ. Interaction of warfarin and nonsystemic gastrointestinal drugs. Clin Pharmacol Ther 1971;12:491-5. PubMed
  11. 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
  12. Fernandez N, Lopez C, Díez R, et al. Drug interactions with the dietary fiber Plantago ovata husk. Expert Opin Drug Metab Toxicol 2012;8(11):1377-86.
  13. 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.
  14. Code of Federal Regulations, Title 21 (21CFR 101.17). Food labeling warning, notice, and safe handling statements. Available at www.ecfr.gov/cgi-bin/text-idx?SID=20f647d3b74161501f46564b915b4048&mc=true&node=se21.2.101_117&rgn=div8. Accessed December 3, 2
  15. Code of Federal Regulations, Title 21 (21CFR 201.319). Specific labeling requirements - water-soluble gums, hydrophilic gums, and hydrophilic mucilloids. Available at www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=201.319. Accessed Dece
  16. 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
  17. Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid. 1998;8(8):667-71. PubMed
  18. 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

See these in context on the Black Psyllium monograph →

Guar Gum 26 references
  1. Gin H, Orgerie MB, Aubertin J. The influence of Guar gum on absorption of metformin from the gut in healthy volunteers. Horm Metab Res 1989;21:81-3.
  2. Huupponen R, Seppala P, Iisalo E. Effect of guar gum, a fibre preparation, on digoxin and penicillin absorption in man. Eur J Clin Pharmacol 1984;26:279-81. PubMed
  3. Malo JL, Cartier A, L'Archeveque J, et al. Prevalence of occupational asthma and immunologic sensitization to guar gum among employees at a carpet-manufacturing plant. J Allergy Clin Immunol 1990;86:562-9. PubMed
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Blond Psyllium 28 references
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Pectin 11 references
  1. Jaakkola MS, et al. Asthma caused by occupational exposure to pectin. J Allergy Clin Immunol 1997;100:575-6. PubMed
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  9. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
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See these in context on the Pectin monograph →

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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.

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