What it is used for

Type 1 diabetes, as mealtime insulin or in an insulin pump
Type 2 diabetes, when other treatments are not enough

Read our guides:

Off-label uses

Doctors sometimes prescribe a medicine for a condition it is not officially licensed for. This is called off-label use. It is legal and common when there is good evidence it helps, and your doctor should explain why they are suggesting it.

Insulin lispro is not commonly used off-label.

How it works

Insulin lispro is absorbed quickly, starting to work in about 15 minutes and lasting 2 to 5 hours. It moves sugar from the blood into cells after a meal.

Side effects

Like all medicines, Insulin lispro can cause side effects, although not everyone gets them. Many are mild and ease after the first few weeks.

Common side effects

low blood sugar (hypos)
redness or swelling where you inject
lumps under the skin
weight gain

Tell your doctor or pharmacist if these bother you or do not go away.

Serious side effects

These are rare. Call 111 or contact your doctor straight away if you get:

a severe hypo with confusion, fits or passing out
swelling of the face or trouble breathing

Call 999 if you have signs of a serious allergic reaction, such as swelling of your lips, mouth, throat or tongue, or trouble breathing.

You can report any side effect to the Yellow Card scheme, run by the medicines regulator.

Stopping and withdrawal

Important safety information

Humalog comes in 100 and 200 units per ml strengths. Check you have the right one.
Always carry fast-acting sugar.

Questions about your medicine?

A pharmacist can answer questions about your medicines for free, without an appointment. You can also ask your GP for a medication review. Check if you can get free prescriptions.