Categories of Insulin

This type of insulin begins acting within 15 minutes
Peak: 0.5-3 hours
Duration: 3-5 hours

Examples of Rapid-Acting Insulin

This type of insulin reaches the bloodstream within 30 minutes
Peak: 2-3 hours
Duration: 3-6 hours

Examples of Regular or Short-Acting Insulin

This type of insulin reaches the bloodstream in 2-4 hours 
Peak: 4-10 hours
Duration: 10-16 hours
Used in combination with rapid or regular insulin

Examples of Intermediate-Acting Insulin

This type of insulin mimics natural basal insulin secretion and starts working in 1.5 hours
Peak: "peakless"
Duration: Up to 24 hours
Supplemented with boluses of rapid or short acting for meals

Examples of Long-Acting or Basal Insulin