In this double-blind, placebo-controlled study, subjects with prediabetes and type 2 diabetes were randomly assigned to the placebo control group or the test (Arginyl-fructose: AF) group. We determined fasting serum levels of glucose, hemoglobin A1c (HbA1c), insulin, and free fatty acids (FFAs), were measured by 2-h oral glucose tolerance tests (OGTTs) at baseline and after the 6-week intervention.

Inclusion Criteria:

- All subjects are with prediabetes (IFG or IGT) or newly diagnosed type 2 DM (T2DM) no taking medicine. IFG was defined as fasting glucose between 100 and 125 mg/dL and IGT was defined as 2-h OGTTs glucose levels 140-199 mg/dL. Newly diagnosed type 2 diabetes was defined as fasting glucose ≥126 mg/dL or 2-h OGTTs level ≥ 200 mg/dL.

Exclusion Criteria:

- Exclusion criteria included 1) glucose lowering medications or insulin injections; 2) abnormal liver or renal function; 3) chronic stomach and intestines disease; 4) chronic alcoholism; 5) pregnancy or intending to become pregnant during time of study. 6) complications; 7) an occupation that could be dangerous if hypoglycemia should occur.