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Diabetes Health Center

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The Facts About Insulin for Diabetes

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Has your doctor told you that you need to take insulin? You'll want to get familiar with what it is and how you use it.

Insulin is a hormone that controls blood sugar. There are many types of insulin used to treat diabetes. They include:

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  • Rapid-acting insulin. This starts to work within a few minutes and lasts for a couple of hours.
  • Regular- or short-acting insulin. It takes about 30 minutes to work fully and lasts for 3 to 6 hours.
  • Intermediate-acting insulin. This takes 2 to 4 hours to work fully. Its effects can last for up to 18 hours.
  • Long-acting insulin. It can work for an entire day.

Your doctor may prescribe more than one type.

You might need to take insulin more than once daily, to space your doses throughout the day, and possibly to also take other medicines. Your doctor will tell you exactly what you need.

How Do I Take It?

There are several methods. You can give yourself an insulin injection using a needle and syringe, a cartridge system, or pre-filled pen systems. Inhaled insulin, insulin pumps, and a quick-acting insulin device are also available.

If you use an injectable insulin, the place on the body where you give yourself the shot may matter. 

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 vary the exact injection spot. This helps minimize scarring under the skin.

What Are the Side Effects?

The major ones include:

  • Low blood sugar
  • Weight gain when you first start using insulin
  • Lumps or scars where you've had too many insulin injections
  • Rash at the site of injection or over the entire body (rare)
  • With inhaled insulin, there's a chance that the lungs could tighten suddenly in people who have asthma or the lung disease COPD.

How Should I Store My Insulin?

If you use injectable insulin, always keep two bottles of each type of your insulin on hand. You can store the bottle that you are using at room temperature (not higher than 80 F) for 30 days. Keep it where it will not get too hot or too cold, and out of direct sunlight.

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