This is to be a randomized, double-blind, placebo-controlled, sequential, multiple oral dose study conducted in normoglycemic healthy subjects (NHS) (Part 1) and subjects with type 2 diabetes mellitus (T2DM) who are treated with monotherapy metformin (a stable dose at randomization) along with diet and exercise (Part 2). Subjects with T2DM who are not on a stable dose of metformin but meet all other entry criteria may be enrolled in the study at the discretion of the Investigator, but must undergo a stabilization period of at least 12 weeks before determining eligibility for the study. In Part 1, a single group of healthy subjects will be dosed with repeated oral doses of 15 mg of LGD-6972 or placebo once daily (QD) for 14 days. In Part 2, a maximum of 3 groups of subjects with T2DM will be dosed with 3 sequential, increasing doses of LGD-6972 (5 mg, 10 mg or 15 mg) or placebo QD for 14 days.