Drug & supplement interaction

Glycomacropeptide + Tolbutamide

Tolbutamide brand name: Orinase.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Glycomacropeptide and Tolbutamide in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Glycomacropeptide and Tolbutamide

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Tolbutamide and Glycomacropeptide in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Glycomacropeptide at all — not against Tolbutamide, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Glycomacropeptide safety at a glance

Glycomacropeptide overall Use caution Generally well tolerated as a food protein, but it is milk-derived and not suitable for those with milk allergy.
Pregnancy Use caution Not enough safety data; use only under medical or dietitian supervision.
Breastfeeding Use caution Not enough safety data; check with your doctor before use.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Tolbutamide and Glycomacropeptide? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Glycomacropeptide Itself Has Been Linked To

This is not an interaction — nothing below involves Tolbutamide. It is the side-effect record for Glycomacropeptide on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Glycomacropeptide, this list is the first place to look.

  • Bloating or gas / Stomach upset / Diarrhea / Nausea Additional detail

    “Orally, the most common side effects of glycomacropeptide are abdominal discomfort, bloating, burping, and flatulence. Taking skim milk powder enriched with glycomacropeptide and G600 milk fat extract for 3 months has been associated with diarrhea, flatulence, and nausea. However, rates of these effects were similar in the control group.”

    Glycomacropeptide · Natural Medicines adverse-effect record, reported in diarrhea.

    3 sources cited
    1. 113396. Delsoglio M, Capener R, MacDonald A, et al. Evaluation of a New Glycomacropeptide-Based Protein Substitute in Powdered and Liquid Format in Patients with PKU. Nutrients 2023;15(16):3580. PubMed
    2. 96291. Dalbeth N, Ames R, Gamble GD, et al. Effects of skim milk powder enriched with glycomacropeptide and G600 milk fat extract on frequency of gout flares: a proof-of-concept randomised controlled trial. Ann Rheum Dis. 2012;71(6):929-34. PubMed
    3. 96292. Ney DM, Stroup BM, Clayton MK, et al. Glycomacropeptide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial. Am J Clin Nutr. 2016;104(2):334-45. PubMed

Everything above comes from the Natural Medicines adverse-effect record for Glycomacropeptide — expand a row for the licensed statement it rests on. We haven’t matched Tolbutamide to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Tolbutamide.

Everything else you take

See Every Supplement That Interacts With Tolbutamide

This page covers Glycomacropeptide only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tolbutamide page lists 305 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), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 2 major · 255 moderate · 48 minor.

From our pharmacist’s overview on the Tolbutamide page

“People take tolbutamide (Orinase) to lower blood sugar in type 2 diabetes, and diabetes is exactly the condition supplement shelves target, which is why this list runs to 305 ingredients and deserves real caution. Of those, 239 also push glucose around, most often downward, so combining them can drive sugar lower than intended.”

Reviewed by 2 · Jul 18, 2026

Open the Tolbutamide interaction page

How much people look this up

Where Glycomacropeptide and Tolbutamide 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 Glycomacropeptide
Steady interest

#1,175 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Tolbutamide
Steady interest

#2,130 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Glycomacropeptide reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Glycomacropeptide and Tolbutamide records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Glycomacropeptide

What is Glycomacropeptide?

  • Phenylketonuria (PKU) nutrition
  • Protein source low in phenylalanine
  • Gut and digestive health
  • Prebiotic support
  • Appetite and satiety

Glycomacropeptide (GMP) is a milk-derived protein fragment best known as a low-phenylalanine protein source used in medical foods for people with phenylketonuria (PKU). It is also being studied for gut health and appetite, but evidence for most non-PKU uses is still limited. Talk to your doctor or dietitian before using GMP products, especially if you have a metabolic condition.

Peptide derived from milk casein (whey-based) · Medical foods, protein powders, capsules, ready-to-drink formulas

An interaction check asks whether these two react with each other — it does not ask whether Glycomacropeptide is a good idea for someone in your situation. Here is what our Glycomacropeptide record says about it on its own.

Glycomacropeptide: dosing

There is no single standardized dose of glycomacropeptide for general use. The right amount depends on why it is being used. For PKU, the amount is carefully calculated by a metabolic dietitian based on a person's protein needs and phenylalanine limits.For protein powders and other supplements, follow the directions on the product label. Avoid taking more than the label suggests.

From our Glycomacropeptide monograph — the full record covers uses, side effects and every documented interaction.

Read the full Glycomacropeptide monograph & all interactions
Medication

About Tolbutamide

What Is Tolbutamide Used For?

Brand name: Orinase

  • Tolbutamide is used along with diet and exercise, and sometimes with other medications, to treat type 2 diabetes (condition in which the body does not use insulin normally and, therefore, cannot control the amount of sugar in the blood). Tolbutamide is in a class of medications called sulfonylureas. Tolbutamide lowers blood sugar by causing the pancreas to produce insulin (a natural substance that is needed to break down sugar in the body) and helping the body use insulin efficiently. This medication will only help lower blood sugar in people whose bodies produce insulin naturally. Tolbutamide is not used to treat type 1 diabetes (condition in which the body does not produce insulin and, therefore, cannot control the amount of sugar in the blood) or diabetic ketoacidosis (a serious condition that may occur if high blood sugar is not treated).

  • Over time, people who have diabetes and high blood sugar can develop serious or life-threatening complications, including heart disease, stroke, kidney problems, nerve damage, and eye problems. Taking medication(s), making lifestyle changes (e.g., diet, exercise, quitting smoking), and regularly checking your blood sugar may help to manage your diabetes and improve your health. This therapy may also decrease your chances of having a heart attack, stroke, or other diabetes-related complications such as kidney failure, nerve damage (numb, cold legs or feet; decreased sexual ability in men and women), eye problems, including changes or loss of vision, or gum disease. Your doctor and other healthcare providers will talk to you about the best way to manage your diabetes.

See full Tolbutamide drug information
Keep checking

Other Drugs & Glycomacropeptide

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Glycomacropeptide list.

See the full Glycomacropeptide interactions page
See every supplement checked against Tolbutamide, ranked by severity
Evidence & sources

Glycomacropeptide References

The 12 references that drive our Glycomacropeptide monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. van Calcar SC, MacLeod EL, Gleason ST, et al. Improved nutritional management of phenylketonuria by using a diet containing glycomacropeptide compared with amino acids. Am J Clin Nutr 2009;89(4):1068-1077. PubMed
  2. Keogh, J. B. and Clifton, P. The effect of meal replacements high in glycomacropeptide on weight loss and markers of cardiovascular disease risk. Am J Clin Nutr 2008;87(6):1602-1605. DOI
  3. Dalbeth N, Ames R, Gamble GD, et al. Effects of skim milk powder enriched with glycomacropeptide and G600 milk fat extract on frequency of gout flares: a proof-of-concept randomised controlled trial. Ann Rheum Dis. 2012;71(6):929-34. PubMed
  4. Ney DM, Stroup BM, Clayton MK, et al. Glycomacropeptide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial. Am J Clin Nutr. 2016;104(2):334-45. PubMed
  5. Daly A, Evans S, Chahal S, et al. Glycomacropeptide: long-term use and impact on blood phenylalanine, growth and nutritional status in children with PKU. Orphanet J Rare Dis 2019;14(1):44. doi: 10.1186/s13023-019-1011-y. PubMed
  6. Tiele A, Daly A, Hattersley J, et al. Investigation of paediatric PKU breath malodour, comparing glycomacropeptide with phenylalanine free L-amino acid supplements. J Breath Res 2019;14(1):016001. doi: 10.1088/1752-7163/ab4097. PubMed
  7. Larsen ER, Juel A, Jensen E, Hollyer TR, Wegener G. Dietary supplementation with casein glycomacropeptide, leucine and tryptophan reduces plasma amino acid levels in men. Acta Neuropsychiatr 2022;34(2):69-76. PubMed
  8. Delsoglio M, Capener R, MacDonald A, et al. Evaluation of a New 'Mix-In' Style Glycomacropeptide-Based Protein Substitute for Food and Drinks in Patients with Phenylketonuria and Tyrosinemia. Nutrients 2023;15(16):3598. PubMed
  9. Delsoglio M, Capener R, MacDonald A, et al. Evaluation of a New Glycomacropeptide-Based Protein Substitute in Powdered and Liquid Format in Patients with PKU. Nutrients 2023;15(16):3580. PubMed
  10. Daly A, Högler W, Crabtree N, et al. A Three-Year Longitudinal Study Comparing Bone Mass, Density, and Geometry Measured by DXA, pQCT, and Bone Turnover Markers in Children with PKU Taking L-Amino Acid or Glycomacropeptide Protein Substitutes. Nutrients 2 PubMed
  11. Pena MJ, Pinto A, de Almeida MF, et al. Continuous use of glycomacropeptide in the nutritional management of patients with phenylketonuria: a clinical perspective. Orphanet J Rare Dis 2021;16(1):84. PubMed
  12. Daly A, Högler W, Crabtree N, et al. Growth and Body Composition in PKU Children-A Three-Year Prospective Study Comparing the Effects of L-Amino Acid to Glycomacropeptide Protein Substitutes. Nutrients 2021;13(4):1323. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Glycomacropeptide and Tolbutamide Together: Common Questions

Is it safe to take Glycomacropeptide with Tolbutamide?
We do not list a known interaction between Glycomacropeptide and Tolbutamide. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Does Tolbutamide interact with any supplements?
Yes. Tolbutamide has documented interactions with 305 supplements in our database — Glycomacropeptide is not one of them. The Tolbutamide interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Glycomacropeptide monograph Uses, safety profile, and every drug interaction in one place Tolbutamide drug information The full plain-English guide to this medication Tolbutamide supplement interactions Every supplement checked against Tolbutamide, 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 References The 12 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Tolbutamide and Glycomacropeptide?

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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.