Drug & supplement interaction

Glycomacropeptide + Interferon Beta-1a

Interferon Beta-1a brand names: Rebif, Avonex.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Glycomacropeptide and Interferon Beta-1a 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 Interferon Beta-1a

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 Interferon Beta-1a 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 Interferon Beta-1a, 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 Interferon Beta-1a 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 Interferon Beta-1a. 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 Interferon Beta-1a 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 Interferon Beta-1a.

Everything else you take

See Every Supplement That Interacts With Interferon Beta-1a

This page covers Glycomacropeptide only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Interferon Beta-1a page lists 57 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Beer (major), Siberian Cocklebur (major), Wine (major), Alfalfa (moderate) and Angelica Archangelica (moderate).

By severity: 3 major · 53 moderate · 1 minor.

From our pharmacist’s overview on the Interferon Beta-1a page

“Siberian cocklebur, an herb tied to documented cases of liver failure, is the first name to know for anyone injecting interferon beta-1a (Rebif, Avonex) for multiple sclerosis. Interferon beta-1a can strain the liver on its own, which is why prescribers order routine liver blood tests, and 38 of the 57 supplements on file carry that sa…”

Reviewed by 2 · Jul 18, 2026

Open the Interferon Beta-1a interaction page

How much people look this up

Where Glycomacropeptide and Interferon Beta-1a 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

#1,174 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Interferon Beta-1a
Steady interest

#2,614 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 Interferon Beta-1a 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 Interferon Beta-1a Intramuscular Injection

What Is Interferon Beta-1a Intramuscular Injection Used For?

Brand names: Rebif, Avonex

  • Interferon beta-1a intramuscular injection is used to treat adults with various forms of multiple sclerosis (MS; a disease in which the nerves do not function properly and people may experience weakness, numbness, loss of muscle coordination, and problems with vision, speech, and bladder control) including:

    • clinically isolated syndrome (CIS; nerve symptom episodes that last at least 24 hours),

    • relapsing-remitting forms (course of disease where symptoms flare up from time to time), or

    • secondary progressive forms (course of disease where relapses occur more often).

  • Interferon beta-1a is in a class of medications called immunomodulators. It works by decreasing inflammation and preventing nerve damage that may cause symptoms of multiple sclerosis.

Most-Reported Side Effects for Interferon Beta-1a

From FAERS, the FDA’s public side-effect reporting system (192,069 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Multiple sclerosis relapse 15,851 reports
Influenza like illness 13,253 reports
Fatigue 11,554 reports
Fall 10,604 reports
Multiple sclerosis 9,358 reports
See full Interferon Beta-1a Intramuscular Injection 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
No interaction 2,829 drugs checked — show the list
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 Interferon Beta-1a Together: Common Questions

Is it safe to take Glycomacropeptide with Interferon Beta-1a?
We do not list a known interaction between Glycomacropeptide and Interferon Beta-1a. 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 Interferon Beta-1a interact with any supplements?
Yes. Interferon Beta-1a has documented interactions with 57 supplements in our database — Glycomacropeptide is not one of them. The Interferon Beta-1a interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Interferon Beta-1a 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.