Study aim: Determining the effect of Oleoylethanolamide oral supplementation on the glycemic index, insulin resistance, and C-reactive protein in pre-diabetic patients Design: In this study, 44 patients with prediabetes who are eligible for inclusion in the study and referred to the Department of Endocrinology and Metabolism of Velayat Hospital of Qazvin University of Medical Sciences are selected. Participants are randomly assigned to two intervention and control groups and each participant is assigned a code. Settings and conduct: This study will be done by referring to the Specialty Hospital of Qazvin University of Medical Sciences. The intervention and control group will receive 125 mg of Oleoylethanolamide or placebo daily for 2 months, respectively. Each person will complete questionnaires of individual consent, physical activity, and 24-hour recall. Fasting blood samples were also collected at the beginning and end of the study in 10 ml from participants. In this study, participants will be randomly divided into two groups (22 persons) through the table of random numbers. Participants/Inclusion and exclusion criteria: Inclusion criteria: willingness to work, prediabetes, age 25- 55, non-modification of treatment and medications for at least the past 2 months, moderate physical activity Exclusion criteria: Pregnancy and lactation, patients with severe renal and hepatic dysfunction, alcohol consumption Intervention groups: Intervention group: the group receiving Oleoylethanolamide (125 mg daily) Control group: placebo group Main outcome variables: Fasting blood sugar, 2 hours sugar, Glycosylated hemoglobin, insulin resistance, an inflammatory factor