Type of insulin	Onset	Peak	Duration
Insulin lispro (Humalog)	5 minutes	1 to 2 hours	3 to 4 hours
Regular insulin	15 minutes	3 to 4 hours	6 to 8 hours
Insulin zinc suspension (Lente) and isophane insulin suspension (NPH)	1 hour	6 to 8 hours	12 hours
Extended insulin zinc suspension (Ultralente)	1 hour	None	24 hours