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What Is Insulin



is a hormone made by the pancreas. Insulin helps remove sugar from your blood and takes it to other parts of your body. This helps lower your blood sugar levels. You may need to take insulin if your pancreas is not making enough. You may also need to take insulin if your body cannot use insulin correctly.

Contact your healthcare provider if:

You have questions or concerns about your condition or care.

Types of insulin:

Several types of insulin are used to lower your blood sugar level. The type tells you how fast the insulin starts to work or how long it lasts in your body. Your healthcare provider will help you find the insulin that is right for you:

  • Rapid-acting insulin starts to work within 15 minutes after you use it. Take it just before or just after you eat.
  • Short-acting, or regular, insulin starts to work within 30 minutes after you use it. Take this insulin 30 to 45 minutes before you eat.
  • Intermediate-acting insulin starts to work 2 to 4 hours after you use it. It reaches the highest level in your blood about 6 to 8 hours after you use it. This type of insulin helps control your blood sugar level between meals. It is commonly used in the morning, at bedtime, or both.
  • Long-acting insulin starts to work 2 to 4 hours after you use it. It can last 24 hours or more in your body. This type of insulin is often taken in the morning or at bedtime. It helps control your blood sugar throughout the day.
  • Premixed insulin is a mixture of 2 types of insulin. It usually includes one type to help control your blood sugar at meals. The other type helps control your blood sugar between meals and while you sleep.

Use insulin safely and check your blood sugar levels:

Some people may need to inject insulin one time each day. Others may need to inject insulin more often. This depends on the type of insulin you use, what you eat, and your activity level. You may also need different amounts of insulin during illness or with certain medicine changes or health conditions.

  • Prepare and give insulin as directed. Always check the label on the bottle to be sure you are using the right insulin. Do not use the same spot on your body each time. Give yourself insulin based on your blood sugar level and directions from your healthcare provider or diabetes specialist. Do not inject insulin within 2 inches of your belly button or into any stretch marks. Do not inject insulin through clothing. This can contaminate the needle and may cause infection.
  • Check your blood sugar level as directed. Some types of insulin can cause your blood sugar level to decrease quickly. Ask your healthcare provider when to check your blood sugar levels during the day. Check it any time you have symptoms of high or low blood sugar levels.
  • Know what your blood sugar levels should be. If you check your blood sugar level before a meal , it should be between 80 and 130 mg/dL. If you check your blood sugar level 1 to 2 hours after a meal , it should be less than 180 mg/dL. Ask your healthcare provider if these are good goals for you.
  • Write down your blood sugar level results. Bring the results to your follow-up appointments. Your healthcare provider may use the results to make changes to your insulin type or dose, eating plan, or exercise plan.

How insulin is measured and given:

  • A needle and syringe is used to inject insulin under the skin. Insulin needles come in different sizes. Do not share needles or syringes with others. Ask your provider or diabetes specialist what needle is best for you. Use the correct size insulin syringe to make sure you get the right dose of insulin.
  • An insulin pen is used to inject insulin under the skin. It looks like a regular pen but has a short needle on one end. An insulin pen has enough insulin in it for a few injections. Some pens have a cartridge of insulin that you change when it is empty. Other pens should be thrown away when the case is empty. Do not share insulin pens with others. Change the needle with each dose.
  • Insulin jet injectors use strong air pressure to spray insulin through the skin. No needles are used with injectors. Ask your provider or diabetes specialist how to safely use your injector.
  • An insulin injection port is a tube on your skin. Insulin is injected through the port. The port can stay in place for several days.
  • An insulin pump is worn outside of your body. The pump gives insulin through a small tube attached to a needle under your skin. A cartridge of insulin is placed in the pump. The pump can give you a continuous amount of insulin throughout the day and night. It can also be programmed to give you a dose of insulin with meals.

  • Inhaled insulin is powdered insulin that you breathe in from an inhaler device into your mouth. This insulin is only used for adults.

How to store and throw away insulin:

Follow the storage directions on the label or package insert that came with the insulin. Do not use your insulin if there are clumps or color changes. Cloudy insulin that has small, white, particles that will not mix should be thrown away. Clear insulin that looks cloudy should be thrown away.

  • Always check the expiration date on your insulin bottle. Do not use insulin beyond its expiration date.
  • Do not store insulin in the freezer, direct sunlight, or the glove compartment of a car. Throw away insulin that has been frozen or exposed to very warm temperatures (above 85°F).
  • You can store opened or unopened insulin in the refrigerator or at room temperature. If you store your insulin at room temperature, keep it in a cool, dry place.
  • If you travel, keep the insulin in a cool pack. This will help make sure the temperature of the insulin stays below 86°F (30°C). Do not leave insulin in direct sunlight.
  • Always throw away your used needles in a hard-sided container with a lid. Some examples include a metal coffee can or laundry detergent bottle. Always keep your insulin bottles or pens out of the reach of children.

Follow up with your doctor as directed:

Write down your questions so you remember to ask them during your visits.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.