Types of Insulin — Complete Guide for Diabetics (2026)
- There are 5 main categories of insulin — each with different onset and duration
- Modern insulin analogues (Lantus, NovoRapid, Tresiba) are more predictable than older insulins
- Insulin pumps and closed-loop systems have transformed Type 1 diabetes management
- 1 unit of insulin lowers blood glucose by approximately 1.5–3 mmol/L (25–50 mg/dL)
- Smart insulin pens and CGM integration now allow almost automated dosing decisions
Understanding Insulin Types
Insulin is classified by its onset of action, peak effect, and duration. Modern diabetes management typically combines a basal insulin (background control) with bolus insulin (meal coverage) — the basal-bolus regimen that most closely mimics normal pancreatic function.
All Insulin Types Explained
| Type | Examples | Onset | Duration | Used For |
|---|---|---|---|---|
| Rapid-acting analogue | NovoRapid, Humalog, Fiasp | 10–20 min | 3–5 hrs | Mealtime bolus — most used |
| Short-acting (regular) | Actrapid, Humulin S | 30–60 min | 6–8 hrs | Older, less common now |
| Intermediate (NPH) | Insulatard, Humulin I | 1–2 hrs | 12–16 hrs | Twice-daily basal (older) |
| Long-acting analogue | Lantus, Levemir, Tresiba | 1–2 hrs | 20–42 hrs | Once-daily basal — standard |
| Ultra-long-acting | Toujeo, Tresiba | 6 hrs | Up to 42 hrs | Flattest basal profile |
| Premixed | NovoMix 30, Humulin M3 | Varies | Varies | Simpler T2D regimen |
Modern Insulin Delivery Devices
Insulin Pens (Standard)
Disposable or reusable pens for subcutaneous injection. Modern pens have half-unit dosing, memory functions, and digital connectivity (NovoPen 6, Tempo Smart Button). Needle sizes have reduced dramatically — 4mm needles cause no more discomfort than 8mm.
Insulin Pumps (CSII)
Continuous subcutaneous insulin infusion — delivers precise amounts 24/7 via a fine cannula. Ideal for Type 1 with highly variable glucose or nocturnal hypoglycaemia. NHS provides pumps for qualifying Type 1 patients.
Closed-Loop Systems (Artificial Pancreas)
Integration of CGM + pump + algorithm = automatic insulin adjustment every few minutes. Available systems: CamAPS FX, Medtronic 780G, Omnipod 5. NHS approved for qualifying Type 1 patients. Studies show HbA1c reduction of 0.5–1.0% and dramatic improvement in time-in-range.