Comparative study to evaluate the effect of l-carnitine plus glimepiride versus glimepiride alone on insulin resistance in type 2 diabetic patients

Diabetes Metab Syndr. Jan-Feb 2019;13(1):167-173. doi: 10.1016/j.dsx.2018.08.035. Epub 2018 Sep 1.


Aim: Insulin resistance (IR) is predominant in type 2 diabetic patients. This study aimed to investigate benefits from adding l-carnitine to ongoing glimepiride compared to glimepiride monotherapy on IR in diabetic patients who failed to achieve their glycemic goals on glimepiride monotherapy.

Methods: 58 patients were recruited from Internal Medicine Department, Tanta University Hospital, Egypt then prospectively randomized to receive their glimepiride dose 2 mg twice daily (group 1) or glimepiride 2 mg twice daily + l-carnitine 1 g m twice daily (group 2) for 6 months. Fasting blood samples were collected at baseline, 3 and 6 months after treatment for analysis of fasting and postprandial blood glucose [FBG &PPBG], glycated hemoglobin [HbA1c %], fasting insulin, extracellular part of insulin regulated aminopeptidase [IRAPe] as a novel marker, tumor necrosis factor-alpha [TNF-α], visfatin and lipid panel. Body mass index [BMI] and homeostasis model assessment of insulin resistance [HOMA-IR] were calculated. Data were statistically analyzed by SPSS using unpaired Student's t-test and one way analysis of variance; p ≤ 0.05 was considered statistically significant.

Results: The obtained data suggested that adding l-carnitine to glimepiride has a significantly beneficial effect on FBG, PPBG, HbA1c, fasting insulin, HOMA-IR index, IRAPe, TNF-α, visfatin and lipid panel parameters but doesn't have effect on BMI and blood pressure.

Conclusion: The co-administration of l-carnitine with glimepiride represents a new therapeutic strategy for better controlling diabetic patients as it resulted in more beneficial effects on direct and indirect biomarkers of insulin resistance than glimepiride alone.

Keywords: Diabetes; Glimepiride; HOMA-IR; Insulin regulated aminopeptidase (IRAPe); Insulin resistance; l-carnitine.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Biomarkers / analysis
  • Blood Glucose / analysis
  • Carnitine / therapeutic use*
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Drug Therapy, Combination
  • Female
  • Follow-Up Studies
  • Glycated Hemoglobin A / analysis
  • Humans
  • Hypoglycemic Agents / therapeutic use*
  • Insulin Resistance*
  • Male
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Sulfonylurea Compounds / therapeutic use*


  • Biomarkers
  • Blood Glucose
  • Glycated Hemoglobin A
  • Hypoglycemic Agents
  • Sulfonylurea Compounds
  • hemoglobin A1c protein, human
  • glimepiride
  • Carnitine