Types of Insulin

Simply put, diabetes is a disorder of the hormone insulin. If you have type 2 diabetes, your body no longer responds properly to the insulin produced in your body. This leads to high blood sugar levels and puts you at risk for dangerous diabetes-related complications, such as nerve damage, kidney damage, heart disease, and blindness. Once diagnosed with diabetes you may or may not require regular doses of insulin to help your body function properly. You may also need other diabetes medications in addition to your regular use of insulin.

How Insulin Works

Treatment with insulin helps keep your blood sugar levels within your target range. Insulin is a hormone, a substance excreted by a glandular organ called the pancreas that causes cells and tissues to act in a specific way. Insulin injections mimic the way naturally produced insulin works. Insulin, whether naturally produced or injected, causes your cells to absorb glucose from your blood, lowering blood sugar levels.

Types of Insulin

Each type of insulin available on the market works in a similar way; they differ only in how fast they start to work and how long their action continues. 

Type of Insulin

Generic Name

(Brand Name)

Time of Onset (How Quickly It Starts Working After Injection)

Peak Time

(When It Reaches Its Most Effective Point After Injection)


(How Long It Continues to Work After Injection)

Rapid-Acting Insulin

Insulin glulisine (Apidra)

Insulin aspart (NovoLog)

Insulin lispro (Humalog)

5 to 30 minutes

30 to 90 minutes

2 to 4 hours

Regular Insulin (Short-Acting Insulin)

Insulin regular (Novolin R, Humulin R)

30 to 60 minutes

2 to 4 hours

3 to 8 hours

Intermediate-Acting Insulin

Insulin NPH human (Novolin N, Humulin N)

1 to 2.5 hours

4 to 12 hours

18 to 24 hours

Long-Acting Insulin

Insulin detemir (Levemir)

Insulin glargine (Lantus)

Ultralente (Humulin U)

1 hour for insulin detemir and insulin glargine

6-10 hours for ultralente

No Clear Peak for insulin detemir and insulin glargine

10-30 hours for ultralente

20 to 26 for insulin detemir and insulin glargine

36 hours for ultralente

Your healthcare team determines the type or types of insulin you need based on your personalized needs. While some people only need one type of insulin, others need a combination of insulin to give them the best coverage.

How Insulin is Made

The only insulin available in the United States is that produced from genetically engineered bacteria. However, some people respond better to insulin derived from the pancreases of cows and pigs. While manufacturers in the U.S. can no longer produce animal insulin, the FDA does allow individuals to import it for personal use.

Administering Insulin

Insulin typically requires administration through the top layer of your skin, so that it reaches the subcutaneous, or fatty, layer of your skin. Various administration options include insulin pumps, insulin jets, syringe injection, and insulin pens. Your healthcare team helps determine how you deliver your insulin based on your personal preferences, needs, and abilities. 

Follow your doctor’s orders explicitly when delivering insulin doses. Failure to do so may result in life-threatening consequences.