 Prospective, multi-center, clinical study of SRT2104 administered orally once daily for 28 consecutive days; randomized, placebo-controlled, double-blind, multiple-dose, inpatientoutpatient study to assess the safety and pharmacokinetics PK of SRT2104 in type 2 diabetic male and female subjects on an existing, stable, background metformin therapy. Approximately 225 subjects aged 30-70, who fulfill the inclusionexclusion criteria, will be enrolled in this study to ensure completion of forty 40 evaluable subjects within each of five dosing groups. Subjects will be evenly randomized to receive SRT2104 at one of five doses, placebo A, 0.25 gday B, 0.5 gday C, 1.0 gday D, or 2.0 gday E, once a day for 28 consecutive days, approximately 15 minutes following consumption of a standardized meal. Subjects will remain on a fixed dose of test material for all dosing days in the study. 