Diabetes

Insulin Types Explained

2025-08-30

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

• American Diabetes Association: Types of Insulin
• NHS — Insulin

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• Coronary Angiography — What to Expect

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