Types of Insulin

Endogenous insulin refers to the insulin made inside the body by the pancreas. Exogenous insulin refers to the insulin made or retrieved from outside of the body. Exogenous insulin is the type of insulin injected or infused via an insulin pump. Many different types of insulin are available through the pharmacy—a prescription and specific instructions from a health-care provider are required.

Exogenous insulins differ by:

• How they are made or where they are retrieved from
• The duration of action—how long they work
• Their onset of action—how quickly it starts working
• When the action peaks—when they are most effective

Rapid-Acting Insulin

• Begins to work about 15 minutes after injection
• Peaks in about 1 hour
• Continues to work for 2 to 4 hours
• Types: Insulin glulisine (Apidra), insulin lispro (Humalog), and insulin aspart (Novorapid)

Regular or Short-Acting Insulin

• Usually reaches the bloodstream within 30 minutes after injection
• Peaks anywhere from 2 to 3 hours after injection
• Is effective for approximately 3 to 6 hours
• Types: Humulin R,

Intermediate-Acting Insulin

• Generally reaches the bloodstream about 2 to 4 hours after injection
• Peaks 4 to 12 hours later
• Is effective for about 12 to 18 hours
• Types: NPH (Humulin N,

Long-Acting Insulin

• Reaches the bloodstream several hours after injection
• Tends to lower glucose levels fairly evenly over a 24-hour period
• Types: Insulin detemir (Levemir) and insulin glargine (Lantus)

Premixed insulin

• Premixed insulin benefits people who have difficulty drawing up insulin out of two bottles and drawing up accurate doses. Premixed insulin is also convenient for people whose diabetes has been maintained on this combination.