Short-acting insulinPrescription only
Regular (Human) Insulin
Injection (vial or pen)
Quick Summary
Regular insulin starts working within 30 minutes and covers mealtime sugar rises.
Type 1 and type 2 diabetes
Gestational diabetes
Hospital care
Medical Uses
Type 1 and type 2 diabetes: Mealtime cover.
Gestational diabetes: When needed.
Hospital care: Emergencies such as ketoacidosis.
How it's taken
Injected under the skin about 30 minutes before meals, as your doctor advises.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Low blood sugar
Most common.
Injection site changes
Rotate sites.
Weight gain
Sometimes.
Interactions
Alcohol
Low sugar risk.
Beta blockers
Mask warning signs.
Critical Warnings
Low blood sugar
Black Box Warning: Shaking, sweating, confusion: take sugar straight away. Tell your doctor if it happens.
Don't skip meals
After injecting.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Human Insulin Injection: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Insulin(opens in a new tab) · NHS