Diabetes

Insulin Types Explained

A guide to the main types of insulin, how they work, onset and duration, and how they fit into diabetes care.

2 min read

Intro

Insulin therapy is central to diabetes management, especially for people with type 1 diabetes and some with type 2. Understanding the different insulin types helps patients, carers, and clinicians tailor treatment to individual needs.

Key Points

  • Four main categories: rapid-acting, short-acting, intermediate-acting, long-acting.
  • They differ by onset, peak, and duration.
  • Often used in combination to mimic natural insulin release.
  • Delivery methods: injection pens, pumps, or syringes.

Types of Insulin

Rapid-acting

  • Examples: Lispro (Humalog), Aspart (NovoRapid), Glulisine (Apidra).
  • Onset: 10–20 minutes.
  • Peak: 1–3 hours.
  • Duration: 3–5 hours.
  • Use: Taken at mealtimes to cover blood sugar rise.

Short-acting (Regular)

  • Examples: Humulin R, Actrapid.
  • Onset: 30 minutes.
  • Peak: 2–4 hours.
  • Duration: 6–8 hours.
  • Use: Mealtime coverage; must inject 30 minutes before eating.

Intermediate-acting

  • Examples: NPH (Humulin N, Insulatard).
  • Onset: 1–2 hours.
  • Peak: 4–12 hours.
  • Duration: 12–18 hours.
  • Use: Often combined with short- or rapid-acting insulin.

Long-acting (Basal)

  • Examples: Glargine (Lantus, Toujeo), Detemir (Levemir), Degludec (Tresiba).
  • Onset: 1–2 hours.
  • Duration: Up to 24–42 hours depending on preparation.
  • Use: Provides baseline insulin between meals and overnight.

Delivery Methods

  • Pens: Most common, prefilled, dose dial.
  • Syringes: Less common, may still be used in some regions.
  • Pumps: Provide continuous basal insulin, with programmable boluses at mealtimes.

Risks & Considerations

  • Main risk: hypoglycemia (low blood sugar).
  • Weight gain is possible with some insulins.
  • Rotation of injection sites helps prevent lipodystrophy.
  • Dosing must be individualized by a clinician.

FAQ

Q: What’s the difference between rapid-acting and short-acting?
Rapid-acting works faster and is taken right at mealtime; short-acting is slower and must be taken earlier.

Q: Can long-acting insulin replace mealtime insulin?
No. Long-acting covers baseline needs; mealtime spikes require rapid or short-acting insulin.

Q: Are biosimilar insulins safe?
Yes, biosimilars undergo rigorous testing and are equally effective.

Further Reading