INS and type 1 diabetes mellitus: Insulin lispro is the active ingredient of Humalog® (Eli Lilly, Indianapolis, IN), a rapid-acting insulin analog (100 U/mL) with faster onset and shorter duration of action than regular (unmodified) human insulin.1 Humalog (Ly-Lis) has been approved and marketed for use by people with type 1 (T1DM) or type 2 (T2DM) diabetes mellitus since 1996.