Independent UK medicine guidance
Can Mounjaro cause low blood sugar?
Mounjaro on its own does not usually cause dangerously low blood sugar. The risk increases substantially when it is used alongside insulin or a sulphonylurea such as gliclazide, glimepiride or tolbutamide. This guide covers the warning signs, what to do, and the driving rules.
When is the risk higher?
When Mounjaro is combined with insulin or a sulphonylurea, hypoglycaemia is listed as very common. Your clinician may need to adjust the dose of those medicines.
Symptoms of low blood sugar
- Shaking
- Sweating
- Sudden hunger
- Dizziness
- Headache
- Weakness or drowsiness
- Irritability or confusion
- A fast heartbeat
- Difficulty concentrating
- Blurred vision
Some people do not experience clear warning symptoms, particularly after living with diabetes for a long time.
What should you do?
Follow the hypo treatment plan given by your diabetes team. This will usually involve checking your glucose level where possible, taking a suitable fast-acting source of sugar and checking again after treatment. Once your glucose has recovered, you may need a longer-acting carbohydrate if your next meal is not due soon.
Always carry an appropriate hypo treatment if you are at risk.
If someone is unconscious or cannot swallow safely, do not give them food or drink. Place them in the recovery position, use glucagon if it is available and you have been trained, and call 999.
Driving and repeated episodes
Do not drive, cycle or operate machinery while experiencing symptoms of hypoglycaemia. People using insulin or certain diabetes medicines must also follow DVLA glucose-monitoring rules.
Tell your diabetes team about repeated or severe hypos. Reduced appetite and smaller meals can change how much insulin or sulphonylurea you require, but any adjustment needs to be planned safely.
Common questions
Does Mounjaro cause low blood sugar on its own?
Mounjaro on its own does not usually cause dangerously low blood sugar. The risk increases substantially when it is used alongside insulin or a sulphonylurea such as gliclazide, glimepiride or tolbutamide, where hypoglycaemia is listed as very common.
What are the warning signs of a hypo?
Shaking, sweating, sudden hunger, dizziness, headache, weakness or drowsiness, irritability or confusion, a fast heartbeat, difficulty concentrating and blurred vision. Some people do not get clear warning symptoms, particularly after living with diabetes for a long time.
Should I reduce my insulin while taking Mounjaro?
Do not reduce or stop insulin yourself. Rapidly reducing insulin can cause serious loss of glucose control and, in some circumstances, diabetic ketoacidosis. Your clinician may need to adjust the dose, but any adjustment needs to be planned safely.
Related guides
Sources: Mounjaro Patient Information Leaflet (eMC) • NHS tirzepatide guidance
Explore other side effects
Tap a point on the body to jump to that symptom, or choose from the full list below. The pink marker shows where you are now.