Drug Interaction Report

Glucosamine and Miglitol: Interaction Details

A pharmacist-reviewed analysis of the Glucosamine and Miglitol interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Miglitol

Glyset®
+

Glucosamine

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Minor
Usually limited clinical impact.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 5 documented Glucosamine interactions, 5 are rated minor — including this one.
Onset
rapid
Evidence
theoretical
Severity
Minor

What happens

Reduced antidiabetic agent effectiveness

Interaction Deep Dive

Glucosamine did not affect hemoglobin A1c in a randomized, double-blind, placebo-controlled trial of 34 patients with well-controlled type 2 diabetes mellitus7. The results of this trial may not apply to patients with uncontrolled diabetes. The Arthritis Foundation has recommended that patients with diabetes monitor their blood glucose more frequently when taking glucosamine (Anon, 2002). Clinical studies are inconclusive regarding the effect of glucosamine on glucose and insulin sensitivity 36245.

Why it happens (mechanism)

Glucosamine may impair insulin secretion through competitive inhibition of glucokinase in pancreatic beta cells and/or alteration of peripheral glucose uptake

Literature reports

2 reports — tap to read

a) Glucosamine did not significantly affect hemoglobin A1c (HbA1c) in a randomized, double-blind, placebo-controlled trial of 34 patients with well-controlled type 2 diabetes mellitus. Patients received glucosamine (Cosamin DS) 1500 milligrams (mg) (n=22) or placebo (n=12) daily for 90 days. The Cosamin DS also contained chondroitin sulfate 400 mg, manganese 5 mg, and ascorbic acid 66 mg. HbA1c increased from a mean baseline of 6.45% to 6.5% in the glucosamine group, and decreased from a mean baseline of 6.25% to 6.09% in the placebo group (not significant). The study had 80% power to detect a difference of greater than 0.3% between groups, and 80% power to detect a difference of 0.15% from before to after treatment in the glucosamine group 1.

b) In a trial of 212 patients without diabetes taking glucosamine for knee osteoarthritis, blood glucose levels were slightly decreased after 3 years versus placebo 2. In a second three-year study of 202 patients without diabetes, 3 patients taking placebo and one patient taking glucosamine were diagnosed with diabetes 3. In 15 patients without diabetes, 12 weeks of glucosamine treatment did not affect fasting glucose, but did increase fasting insulin versus placebo (p = 0.01) 4. In 5 healthy subjects, intravenous glucosamine sulfate reduced glucose tolerance and insulin sensitivity under hyperglycemic conditions 5, whereas glucosamine infusion did not affect insulin-induced glucose uptake in 18 healthy subjects 6.

Common questions

Can I take Glucosamine and Miglitol together?

Reduced antidiabetic agent effectiveness Always confirm with your pharmacist or prescriber before making any change.

How serious is the Glucosamine and Miglitol interaction?

It is rated minor. Usually limited clinical impact.

How quickly could this interaction happen?

The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Glucosamine or Miglitol need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there anything you'd monitor while I'm on both?

References (7)

  1. Scroggie DA, Albright A, & Harris MD: The effect of glucosamine-chondroitin supplementation on glycosylated hemoglobin levels in patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized clinical trial. Arch Intern Med 2003; 163(13):1587-1590. PubMed
  2. Reginster JY, Deroisy R, Rovati LC, et al: Long-term effects of glucosamine sulfate on osteoarthritis progression: a randomized, placebo-controlled clinical trial. Lancet 2001; 357(9252):251-256.
  3. Pavelka K, Gatterova J, Olejarova M, et al: Glucosamine sulfate use and delay of progression of knee osteoarthritis: a 3-year, randomized, placebo-controlled, double-blind study. Arch Intern Med 2002; 162(18):2113-2123. PubMed
  4. Almada A, Harvey P, & Platt K: Effects of chronic oral glucosamine sulfate on fasting insulin resistance index (FIRI) in non-diabetic individuals. FASEB J 2000; 14(4):A750.
  5. Monauni T, Zenti MG, Cretti A, et al: Effects of glucosamine infusion on insulin secretion and insulin action in humans. Diabetes 2000; 49(6):926-935. DOI
  6. Pouwels MJ, Jacobs JR, Span PN, et al: Short-term glucosamine infusion does not affect insulin sensitivity in humans. J Clin Endocrinol Metab 2001; 86(5):2099-2103. DOI
  7. Scroggie DA, Albright A, & Harris MD: The effect of glucosamine-chondroitin supplementation on glycosylated hemoglobin levels in patients with type 2 diabetes mellitus: a placebo-controlled,double-blinded, randomized clinical trial. Arch Intern Med 2003; 163(13):1587-1590. PubMed
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.