Types of Insulin

Insulin is classified as:

All insulin prescribed in the U.S. is chemically similar to human insulin. Human insulin is manufactured using recombinant DNA technology and has replaced insulin derived from pork and beef organs. Beef insulin differed from human insulin at 3 amino acid sites and pork insulin differed at one site. As a result, beef and pork insulin caused more allergic reactions and are no longer sold in the U.S.

Each insulin preparation has a different pharmacokinetic profile, i.e., onset, peak effect, and duration. To further complicate things, dosage can significantly modify the profile even within the same commercial product.

Therefore replacing one insulin product with another is not a simple substitution. Changing an insulin medication should only be done under the supervision of a health professional with expertise in diabetes management. If a patient is admitted to the hospital, the type of insulin he or she has been using should not be changed indiscriminately. In all instances of insulin use, dosages must be individualized and balanced with medical nutrition therapy and exercise.

Instant Feedback:

Pork and Beef based insulin have been withdrawn from the U.S. market due to side effects.

Ultra-rapid insulin - Afrezza is an inhaled human insulin, recently approved by the FDA, for use by adult patients with diabetes mellitus (DM). In patients with type 1 DM (T1D), Afrezza must be used in conjunction with a long-acting insulin. Afrezza is rapidly absorbed with a peak serum concentration occurring within 12-15 minutes and a half-life of ≈28-39 minutes. Peak action occurs in about 60 minutes and a duration of about 160 minutes. Afrezza is intended to be taken just before meals. Afrezza appears to improve glycemic control for type II DM patients compared with bolus subcutaneous insulin. Because Afrezza is cleared rapidly from the body, there appears to be less weight gain than that associated with the longer half-life of the rapid-acting insulin analogs. The short half-life is also believed to be responsible for lower incidence of hypoglycemic events.

Rapid-acting insulin analogs are similar to human insulin with minor structural or amino acid changes. They include lispro, aspart and glulisine. They are the fastest acting injectible insulins, used for bolus therapy at mealtime and to correct hyperglycemia. They reach the bloodstream in ≈15 minutes or less after subcutaneous injection, peak action between 30 and 180 minutes, and a maximum duration of action between 2 and 6 hours. They should be injected 5-10 minutes before a meal.

Short acting or Regular insulin usually reaches the blood within 30 minutes after injection, peaks in 2 to 5 hours and stays in the bloodstream for 4 to 12 hours, (Humulin R and Novolin R). Because of it’s short and predictable peak action, regular insulin is the insulin product routinely used for intravenous administration. Insulin concentrations currently available in the U.S. are U-100 and U-500, indicating 100 units or 500 units per milliliter. U-500 is only used in rare cases of insulin resistance when the patient requires extremely large doses. Travelers should be aware that insulin is available in a U-40 strength outside the U.S. To avoid dosing errors, syringes that match the concentration of U-40 insulin must be used.

Instant Feedback:

U-40 is the insulin preparation most commonly used in the U.S.


Intermediate acting (NPH) insulins are human insulin isophane suspensions. They are loudy/ milky suspension of human insulin with protamine and zinc. The addition of protamine or zinc delay relay availability of the insulin, resulting in slower onset, slower peak effect and longer duration. They reach the bloodstream1 to 2 hours after injection, peak within 4 to 12 hours and stay in the bloodstream for 14 to 24 hours. (Humulin N and Novolin N)

Long Acting Insulins These insulins have no peak or a very small peak effect 10 to 16 hours after injection. Depending on dose they can remain active in in the bloodstream for 22-24 hours or longer.

Insulin Inhaled Brand/generic name
Onset in minutes
Afrezza/ rDNA Human powder
12 -14 min.
≈1 hour
180 min.
Beginning of meal
Insulin (SubQ) Brand/generic name
Onset in minutes
Peak effect
(insulin analogs)
Novolog/insulin aspart

12 - 18 min.

1-3 hours

2 - 5 hours

5-10 min. before meal

Humalog/ insulin lispro
15 - 30 min.
.5 - 2.5 hours
2 - 4 hours
<15 min. before meal
Apidra/insulin gluisine
12 - 30 min.
1.6 - 2.8 hours
3 - 4 hours
15 min. before meal
  • Humulin R/ regular insulin
  • Novolin R/ regular insulin
30 min.
2.5 - 5 hours
4 - 12 hours
30 min. before meal
  • Humulin N/insulin NPH
  • Novolin N/insulin NPH
8 hours
12 to 16
(insulin analogs)
  • Levemir/insulin detemir
3-4 hours
3-9 hours

5.7-24 Hrs

  • Lantus/insulin glargine
3-4 hours
No peak
≈ 24 Hrs
Pre-mixed Insulins Brand/generic name
Onset in minutes
  Novolin® 70/30 -
Humulin® 70/30
30-60 min
2-12 hours
18 - 24 hours
30 min. between doses
30 min. before meals
Novolog® Mix 70/30
10 - 20 min 1-4 hours 18 - 24 hours
10-20 min. between doses
and before meals
  Humalog® Mix 75/25        

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