Most side effects from Mounjaro are mild to moderate and tend to ease as your body adjusts. They are most common in the first few weeks of treatment and after each dose increase.
Most common side effects
- Nausea — affects around 1 in 4 patients, usually most noticeable after a dose increase
- Diarrhoea or constipation
- Reduced appetite — this is part of how the medication works
- Abdominal discomfort or bloating
- Tiredness
- Burping or reflux
- Injection site reactions — small lumps, redness, or itching
Less common
- Dizziness or lightheadedness
- Hair thinning (linked to rapid weight loss, not the medication itself)
- Changes to taste
How to manage them
- Eat smaller, more frequent meals
- Avoid greasy, fried, or very rich foods
- Stay hydrated — sip water throughout the day
- Eat slowly and stop when full
If a side effect is severe, persistent, or you're worried, contact our team. See our article on when to seek urgent help for warning signs that need immediate attention.
If you have any concerns about your treatment, contact our support team. For medical emergencies, call 999 or 111.