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Insulin - Introduction

Insulin Action

Insulin’s action has three parts:

• Onset is how long it takes insulin to start working.
• Peak is when insulin is working its hardest.
• Duration is how long insulin will keep working.

The times for onset, peak, and duration are usually given as ranges because insulin may work slower or faster in different individuals.

Insulin Strength

Insulin comes dissolved in liquids. Many people use U-100 insulin which means that there are 100 units of insulin per milliliter of fluid. It is important to use a syringe that matches the strength of your insulin. For example if you use U-100 insulin, use a U-100 syringe.

Insulin Storage

Unopened insulin should be stored in your refrigerator. Since extreme temperatures can destroy insulin, you should not store insulin in your freezer or allow it to warm in the sun. After opening a bottle of insulin, you may keep it at room temperature for up to a month.

Insulin Safety

If the expiration date on your insulin has already passed, you should not use that bottle. Even if the insulin has not expired, you should still examine its appearance to make sure that it is safe to use. Insulins Aspart®, Lispro®, Glarine®, and Regular should appear clear with no particles or color. NPH, lente, and ultralente insulins should be cloudy but should not have any particles or crystals. If your insulin does not look as it should, you should not use it.

This handout contains general information on diabetes medication. It is not intended to replace medical advice. It is important to talk to your doctor or pharmacist about your dosage and any other questions that you may have.