Insulin is a hormone made in your pancreas, which lies just behind your stomach. It helps your body use glucose for energy. Everyone with Type 1 diabetes and some people with Type 2 diabetes need to take insulin to control their blood glucose levels (also called blood sugar levels).
What is insulin?
Insulin is a hormone. It’s made in the beta cells of the pancreas, and one of its main roles is to help regulate, or control, your blood sugar. When there’s enough insulin in the body, it helps to keep your blood sugar from going too high. In people who don’t have diabetes, blood sugars are very carefully and tightly controlled, staying within a safe range. After a person without diabetes eats a meal, the pancreas releases insulin. The insulin then signals muscle, fat, and liver cells in the body to absorb glucose from the bloodstream to be used for energy. In this sense, insulin is like a key that unlocks the doors of the cells to allow glucose to enter. You can also think of insulin as a “storage” hormone, since when there’s more glucose than the body needs, insulin helps the body store that excess glucose in the liver to be used at a later time. Insulin also signals the liver to stop releasing glucose into the bloodstream.
How to Take It?
Many people get insulin into their blood using a needle and syringe, a cartridge system, or pre-filled pen systems. The place on the body where you give yourself the shot may matter and depends on the person. You'll absorb insulin the most consistently when you inject it into your belly. The next best places to inject it are your arms, thighs, and buttocks. Make it a habit to inject insulin at the same general area of your body, but change up the exact injection spot. This helps lessen scarring under the skin. Inhaled insulin, insulin pumps, and a quick-acting insulin device are also available.
Types of Insulin
- Rapid-acting insulin, begins to work about 15 minutes after injection, peaks in about 1 hour, and continues to work for 2 to 4 hours. Types: Insulin glulisine (Apidra), insulin lispro (Humalog), and insulin aspart (NovoLog)
- Regular or Short-acting insulin usually reaches the bloodstream within 30 minutes after injection, peaks anywhere from 2 to 3 hours after injection, and is effective for approximately 3 to 6 hours. Types: Humulin R, Novolin R
- Intermediate-acting insulin generally reaches the bloodstream about 2 to 4 hours after injection, peaks 4 to 12 hours later, and is effective for about 12 to 18 hours. Types: NPH (Humulin N, Novolin N)
- Long-acting insulin reaches the bloodstream several hours after injection and tends to lower glucose levels fairly evenly over a 24-hour period. Types: Insulin detemir (Levemir) and insulin glargine (Lantus)
The role of insulin in the body
- Regulate sugar in your bloodstream. The main job of insulin is to keep the level of glucose in the bloodstream within a normal range. After you eat, carbohydrates break down into glucose, a sugar that serves as a primary source of energy, and enters the bloodstream. Normally, the pancreas responds by producing insulin, which allows glucose to enter the tissues.
- Storage of excess glucose for energy. After you eat, excess glucose is stored in the liver in the form of glycogen. Between meals, the liver releases glycogen into the bloodstream in the form of glucose. This keeps blood sugar levels within a narrow range.
Insulin therapy can be demanding, but it doesn't have to dictate your life. By choosing a program that fits your needs and lifestyle, you can prevent diabetes complications and lead an active, healthy life.