"Vinegar Improves Insulin Sensitivity to a High-Carbohydrate Meal in Subjects With Insulin Resistance or Type 2 Diabetes"
Full Study
I would hope that it works in those of us who aren't diabetic.
One particular phrase interested me: "Acetic acid has been shown to suppress disaccharidase activity (3) and to raise glucose-6-phosphate concentrations in skeletal muscle (4); thus, vinegar may possess physiological effects similar to acarbose or metformin. "
I doubt acetic acid is as powerful as Metformin as an insulin sensitizer.
Remember, Acetyl-L-Carnitine is Acetic Acid and L-Carnitine together.