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What Is Insulin



is a hormone made by the pancreas. Insulin helps your body use sugar for energy. It removes sugar from your blood and 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. Each type of insulin has a different onset, peak, and duration. The onset is how soon the insulin starts to lower your blood sugar levels. The peak is when the insulin has the greatest effect on your blood sugar level. The duration is how long the insulin continues to lower your blood sugar level. Ask your healthcare provider which type of insulin you need, how often to take it, and how to use it. The following are types of insulin:

  • Rapid-acting insulin will lower your blood sugar level quickly. Inject this insulin no more than 15 minutes before you eat a meal.
  • Regular or short-acting insulin helps control your blood sugar level during meals. Inject this insulin 30 to 45 minutes before you eat a meal.
  • Intermediate-acting insulin helps control your blood sugar level between meals. You may need intermediate-acting insulin in the morning, at bedtime, or both. Intermediate-acting insulin may look cloudy.
  • Long-acting insulin will help keep your blood sugar level the same throughout the day. You may take this type of insulin in the morning or at bedtime.
  • Premixed insulin is a combination of 2 types of insulin. The combination is usually a rapid-acting or short-acting insulin mixed with an intermediate-acting insulin. The rapid-acting or short-acting insulin will control your blood sugar levels at meals. The intermediate-acting insulin will control your blood sugar levels between meals.
  • Inhaled insulin is a spray that you inhale through your nose. This insulin begins working within 12 to 15 minutes.

Use insulin safely and check your blood sugar levels:

  • Prepare and give insulin as directed. Make sure you prepare and use your insulin correctly. Give yourself insulin based on your blood sugar level and directions from your healthcare provider. Ask him if you have questions.
  • Check your blood sugar level at least 3 times each day. 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.
  • Ask your healthcare provider how to manage your diabetes during sick days. You may need different amounts of insulin during illness. You may also need different amounts during stress, travel, or when you change your diet or activity.

How insulin is measured and given:

Insulin is measured in units. U100 is the most common type of insulin. It has 100 units of insulin in 1 mL of solution. U500 insulin has 500 units of insulin in 1 mL. Insulin is usually given in the following ways:

  • A syringe is used to inject insulin under the skin. Use the correct size insulin syringe to make sure you get the right dose of insulin. For example, you must inject U100 insulin with U100 syringes. A different syringe is needed for U500 insulin. Your healthcare provider or pharmacist will help you find the right size syringe. The syringe will have measurements in mL and units.
  • An insulin pen is used to inject insulin under the skin. It contains a cartridge of insulin that is attached to a disposable needle. You can turn a dial on the pen to change the dose of insulin.
  • An insulin pump is worn outside of your body. The pump gives insulin through a small tube attached to a needle under your skin. 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 after meals.

How to store 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.

Follow up with your healthcare provider as directed:

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

Further information

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