Support for the efficacy of G. sylvestre in management of both type 1 and type 2 diabetes comes from two earlier controlled, open-label clinical trials, where G. sylvestre extract (400 mg /day) has been given orally to 27 patients with type 1 diabetes as supplement to insulin therapy for 16–18 months [53] and to 22 patients with type 2 diabetes as supplement to conventional drug therapy [54]. This evidence concerns the gene INS and type 2 diabetes mellitus.