Nutraceutical compositions comprise biotin in an amount sufficient to administer to a subject a daily dosage of 0.01 mg per kg body weight to about 3 mg per kg body weight and at least one additional component selected from pantethine or a metabolite thereof, EGCG, phytanic acid, lipoic acid and policosanol. The compositions are useful for the treatment of both type 1 and 2 diabetes, and for the prevention of type 2 diabetes in those individuals with pre-diabetes, or impaired glucose tolerance (IGT) or obesity.