Insulin-Requiring Type 2 Diabetes Mellitus
If you have type 2 diabetes and other treatments are no longer keeping your blood sugar within a healthy range, your healthcare provider may prescribe insulin. This doesn’t mean your diabetes has become type 1 or that you’ve failed to manage it properly—it’s simply another treatment option that can help keep you healthy.
Table of contents
- What Is Insulin and Why You Might Need It
- When Insulin Is Needed for Type 2 Diabetes
- Types of Insulin Used in Treatment
- How Insulin Is Taken
- Concerns and Side Effects of Insulin Therapy
- Combining Insulin with Other Medications
- Monitoring Blood Sugar and Adjusting Insulin
What Is Insulin and Why You Might Need It
Insulin is a hormone naturally made by your pancreas (an organ in your stomach area). Its main job is to help your body use sugar from food for energy. Insulin acts like a key that opens the doors of your cells, allowing sugar to move from your blood into your cells where it can be used.[1]
- Pancreas
In people with type 2 diabetes, the body either doesn’t make enough insulin or doesn’t use it properly (called insulin resistance). Over time, the cells in your pancreas that make insulin can wear out and produce less and less of it. Research shows that these cells fail at a rate of about 4 percent each year.[4] By the time type 2 diabetes is diagnosed, up to half of these insulin-producing cells may not be working properly.[4]
When your body can’t make enough insulin or use it effectively, sugar builds up in your blood instead of entering your cells. This leads to high blood sugar levels, which can damage your heart, kidneys, eyes, and nerves over time if not controlled.[2]
When Insulin Is Needed for Type 2 Diabetes
You’ll need insulin for type 2 diabetes if other diabetes medicines no longer work well enough to keep your blood sugar within a healthy range.[7] Insulin therapy is often recommended when your A1C level (a measure of your average blood sugar over the past few months) is greater than 9 percent, or if diabetes remains uncontrolled despite taking oral medications.[4]
Sometimes you may only need insulin temporarily. For example, you might need it if you’re pregnant, if you’re ill, or to bring your blood sugar down quickly when you’re first diagnosed.[7] In other situations, you may need it for medical procedures or when your body is under stress from illness.[5]
Around one in four people with type 2 diabetes take insulin as part of their treatment.[21] Starting insulin doesn’t mean you have type 1 diabetes—you still have type 2 diabetes but you’ve changed treatment. It’s not your fault if you need insulin, and it doesn’t mean you haven’t managed your diabetes well.[21]
Types of Insulin Used in Treatment
There are different types of insulin that work at different speeds in your body. Your doctor will recommend the type that’s best for you based on your needs.[7]
Long-acting or intermediate-acting insulin is usually taken once or twice a day. This type helps control your blood sugar throughout the day and night. Common intermediate-acting insulins include brand names like Humulin I or Insulatard. Long-acting insulins include brands like Levemir, Lantus, Toujeo, Tresiba, Semglee, or Abasaglar.[7]
If long-acting or intermediate-acting insulin alone doesn’t lower your blood sugar enough, you may also need to take rapid-acting or short-acting insulin before meals. Rapid-acting insulin brands include NovoRapid, Fiasp, Trurapi, Admelog, Humalog, Lyumjev, or Apidra. Short-acting insulin brands include Actrapid or Humulin S.[7]
Biphasic (mixed) insulin combines both intermediate and rapid-acting insulin in one injection. This type is taken before meals, usually 1 to 3 times a day. While it’s less flexible than separate injections, it means fewer shots. Brand names include NovoMix, Humalog Mix, or Humulin M3.[7]
When starting insulin, your doctor may begin with what’s called augmentation therapy, starting at 0.3 units per kilogram of your body weight. If you need more complete insulin coverage (replacement therapy), the starting dose is typically 0.6 to 1.0 units per kilogram.[4]
How Insulin Is Taken
Insulin must be injected because it would be broken down by your digestive system if you swallowed it as a pill. The good news is that injecting insulin doesn’t usually hurt. The needles are very small because you only inject a small amount just under your skin.[7]
You can inject insulin using an insulin pen, which is a device that helps you inject safely and take the right dose. Your diabetes nurse will show you where to inject and how to use your pen.[7] People with type 2 diabetes might inject insulin anywhere from once a day to several times a day, depending on the type of insulin and treatment plan.[6]
There are also other ways to take insulin, including syringes with needles, insulin pumps, and even inhalable forms of insulin.[1]
Concerns and Side Effects of Insulin Therapy
While insulin is an effective treatment, it does have some potential side effects that you should know about.
Low blood sugar (hypoglycemia) can happen if you take too much insulin compared to the amount of food you eat, or if you exercise more than usual or drink alcohol. Low blood sugar occurs when your glucose level drops below 70 mg per dL. Symptoms should be treated right away with a fast-acting carbohydrate like juice or glucose tablets, and your blood sugar should be rechecked after 15 minutes.[4] Studies show that hypoglycemia is more common with premixed and bolus (mealtime) insulin compared to basal (long-acting) insulin.[4]
Weight gain is another common side effect of insulin therapy. This happens because insulin has effects that build up tissues in the body, can increase appetite, may cause you to eat more to prevent low blood sugar, and helps your body retain calories that would otherwise be lost in urine as sugar. In one large study, patients with type 2 diabetes taking insulin gained an average of about 4 kilograms (nearly 9 pounds), though this was associated with better blood sugar control.[4] Weight gain is more common with bolus insulin than with basal insulin.[4]
Even with help from your doctor and diabetes nurse educator, it may take some time to find the right insulin dose to reduce your blood sugar to your target levels.[6] Insulin regimens should be adjusted every three or four days until your blood sugar targets are reached.[4]
Combining Insulin with Other Medications
When you start insulin, you typically don’t stop all your other diabetes medications right away. In fact, continuing some oral medications can be beneficial. Metformin (a common diabetes pill) should be continued if possible because research shows it reduces death from all causes and heart-related events in overweight patients with diabetes.[4]
Studies show that taking metformin combined with insulin leads to less weight gain, a lower insulin dose needed, and less hypoglycemia compared with insulin alone.[4] However, oral medications should not be stopped suddenly when starting insulin because of the risk of blood sugar bouncing back too high.[4]
Your doctor may also add insulin to other forms of therapy you’re already taking. Various combinations can work together to provide benefits tailored to your individual needs.[5]
Monitoring Blood Sugar and Adjusting Insulin
Regular monitoring of your blood sugar levels is essential when taking insulin. Your fasting blood sugar readings (taken before eating) should be used to adjust your basal (long-acting) insulin dose. Both before-meal and after-meal blood sugar readings should be used to adjust your mealtime insulin.[4]
The recommended blood sugar goals are typically 80 to 130 mg per dL before meals and less than 180 mg per dL two hours after eating.[4] However, these targets should be individualized based on many factors including your age, how long you’ve had diabetes, other health conditions, your risk of low blood sugar, and your personal preferences.[11]
Adjusting your insulin dose over time is critical to improving blood sugar control and preventing diabetes-related complications.[4] Your healthcare team will work with you to find the right doses and timing for your insulin injections. This process takes patience and regular monitoring, but it helps ensure that insulin therapy effectively reduces your chances of developing serious long-term problems that can damage your heart, kidneys, eyes, and nerves.[7]
