Diabetes: Types of Insulin

Insulin is either injected under the skin or inhaled into the lungs.

• The onset is when it starts lowering your blood sugar, also called glucose.
• The peak is when it works the strongest.
• The duration is how long it works.

Insulin comes in different strengths. The most common strength is U-100, or 100 units per 1 mL of insulin. Make sure you're using the right strength of insulin with the right syringe.

Types of insulin

Rapid-acting insulin:

• Onset: Within 15 minutes.
• Peak: About 1–2 hours.
• Duration: 2–4 hours.
• Works well when taken right before a meal to quickly lower your blood sugar.
• This type of insulin is available as an injection and an inhaler. You and your health care provider will decide which one is best for you.

Short-acting insulin:

• Onset: Within 30 minutes.
• Peak: 2–3 hours.
• Duration: 3–6 hours.
• Should be taken about 30 minutes before you start eating a meal.

Intermediate-acting insulin:

• Onset: Within 1.5–4 hours.
• Peak: 4–12 hours.
• Duration: 12–18 hours.
• Lowers your blood sugar for a longer period of time. But it doesn't work as well for lowering blood sugar right after a meal. Usually used one or two times a day.

Long-acting insulin:

• Mimics the small amount of insulin that your pancreas usually makes throughout the day.
• Onset: Within 2 hours.
• Peak: There is no peak. Long-acting insulins lower blood sugar levels evenly throughout the day.
• Duration: At least 24 hours. Long-acting insulins should be used one or two times a day.

Concentrated insulin:

The concentration of insulin is the number of units of insulin in 1 milliliter (mL). Insulin vials and injection pens often have a concentration of 100 units in 1 mL (100 units/mL), which is called U-100.

Higher concentrations of insulin are also available. These are helpful for people who need high doses of insulin, usually more than 100 units per day. Concentrated insulin delivers the same amount of insulin but in a smaller volume.

• Humulin (regular insulin, U-500) has 500 units per 1 mL of insulin. This insulin should only be used with the U-500 syringe. It's also available as a U-500 prefilled insulin pen. Do not use another type of syringe with this insulin. Using the wrong type of syringe can cause serious problems such as low blood sugar.
• Humalog (insulin lispro, U-200), Lyumjev (insulin lispro, U-200), and Tresiba (insulin degludec, U-200) have 200 units per 1 mL of insulin. These insulins are only available as a U-200 pen.
• Toujeo (insulin glargine, U-300) has 300 units per 1 mL of insulin. This insulin is only available as a U-300 pen.