About Insulin


Insulin is a peptide hormone, produced by beta cells of the pancreas, and is central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, skeletal muscles, and fat tissue to absorb glucose from the blood. In the liver and skeletal muscles, glucose is stored as glycogen, and in fat cells it is stored as triglycerides.

  • Insulin regulates sugar in your bloodstream
  • Insulin stores excess glucose for energy
  • Insulin is usually injected under the skin. In some cases, a pump delivers the insulin on a continuous basis
  • It is possible that different types of insulin may need to be mixed together, to get optimal blood glucose control. Insulin shots may be required between one and four times a day

Risks of Insulin

Insulin is proven to lower blood sugar levels when used as part of an overall diabetes treatment plan, which may include diet, exercise, and other diabetes medicines.

One of the most common side effects of taking insulin is experiencing excessively low blood sugar (hypoglycemia). While taking insulin, one should limit the level of physical activities and increase food consumption. Failing to do so might also result in hypoglycemia. Allergic reactions to insulin are possible, though rare. If hyperglycemia, hypoglycemia, itching, a rash or hives, breathlessness, swelling or redness at the injection site or skin changes occurs, consult your physician.

Types of Insulin

Since its discovery in 1921, many varieties of insulin have been developed to satisfy specific needs of patients with diabetes.

  • Short-acting insulin
    • Regular insulin, insulin lispro, insulin aspart, insulin glulisine
    • Duration of action is 3 to 6 hours
  • Intermediate-acting insulin
    • NPH (Neutral Protamine Hagedorn) insulin
    • Duration of action is 10 to 16 hours
  • Long-acting insulin
    • Insulin glargine, insulin detemir
    • Duration of action is 20 to 24 hours

Classification of Insulin

Preparation Onset of action*
Peak effect§
Duration of action£
Short-acting Aspart <0.25 0.5–1.5 3–4
Glulisine <0.25 0.5–1.5 3–4
Lispro <0.25 0.5–1.5 3–4
Regular 0.5–1.0 2–3 4–6
Intermediate-acting NPH 1–4 6–10 10–16
Long-acting Glargine 1–4 Minimal peak 20–24
Detemir 1–4 Minimal peak 20–24
Premixed Insulin 30/70
30% regular, 70% NPH
0.5–1 10–16
Insulin 50/50
50% regular, 50% NPH
0.5–1 10–16
Lispro 25/75
25% lispro, 75% protamine lispro
<0.25 Up to 10–16
Lispro 50/50
50% lispro, 50% protamine lispro
<0.25 Up to 10–16
Aspart 30/70
30% aspart, 70% protamine aspart
<0.25 Up to 10–16