What happens during your first week on Mounjaro?
Starting Mounjaro can feel like a significant step in your weight-loss treatment. During the first week, some people notice changes in appetite quite quickly, while others experience very little difference initially.
This does not necessarily mean the medicine is not working.
Mounjaro contains tirzepatide and is given as a once-weekly injection. Treatment normally begins at a lower dose so your body has time to adjust before the dose is increased gradually. The official UK patient information should always be followed together with the instructions given by your prescriber.
Will Mounjaro reduce my appetite in the first week?
It may.
Some people report feeling:
- less hungry between meals
- satisfied after smaller portions
- less interested in snacking
- fuller for longer after eating
Others may not notice a major appetite change during the first week.
Weight-loss treatment should not be judged by the first few days alone. Mounjaro treatment is designed to be used over time alongside dietary and physical-activity changes.
Should I expect to lose weight in Week 1?
You may see the number on the scales change during your first week, but there is no specific amount of weight you should expect to lose.
Early changes in body weight can also be affected by:
- fluid levels
- food intake
- bowel movements
- salt intake
- menstrual cycle
- physical activity
It is therefore usually more useful to monitor your progress over several weeks rather than concentrating on individual daily weigh-ins.
Common Mounjaro side effects
Like all medicines, Mounjaro can cause side effects.
Gastrointestinal symptoms are among the effects patients may experience, particularly while adjusting to treatment. You should read the patient information leaflet supplied with your medicine for the complete and current list of possible side effects and warnings.
If you experience symptoms that are severe, persistent or concerning, contact your prescriber or another healthcare professional.
What should I eat during my first week?
There is no special “Mounjaro diet”.
However, because your appetite may decrease, it can help to concentrate on nutritious foods rather than simply eating much less.
Try to include:
Protein: tofu, eggs, Greek yoghurt, cottage cheese, beans, lentils or other suitable protein sources.
Vegetables and fruit: aim for a varied selection throughout the week.
Fibre: whole grains, vegetables, beans and pulses can help maintain a balanced diet.
Fluids: continue drinking regularly, especially if you are eating less than usual.
Mounjaro for weight management is intended to be used alongside a reduced-calorie diet and increased physical activity.
What if I don't feel anything?
Don't panic.
The starting phase is not designed to produce an identical response in everybody.
Do not increase your dose yourself because you feel the medicine is not working quickly enough. Take Mounjaro according to the schedule prescribed for you.
Your prescriber can review your treatment and decide whether dose changes are appropriate.
Can I exercise during Week 1?
For most people, physical activity remains an important part of a weight-management programme.
You don't suddenly need to start an intensive training programme because you've started Mounjaro.
Walking, resistance training, cycling, swimming and other forms of activity can all form part of a sustainable routine according to your individual health and circumstances.
When should I contact a healthcare professional?
Seek medical advice if you develop symptoms that are severe, persistent or unusual.
You should also make sure your prescriber knows about your medical history and other medicines you are taking, as these can affect whether Mounjaro is appropriate for you.
Always refer to the latest patient information leaflet for important warnings and advice about serious side effects.
Mounjaro Week 1 checklist
At the end of your first week, it can be useful to make a note of:
- your weight
- appetite level
- portion sizes
- any side effects
- how much fluid you are drinking
- physical activity
- how you generally feel
This gives you and your prescriber useful information when reviewing your progress.
What happens next?
Your first week is only the beginning.
Over the coming weeks, you may notice further changes in appetite, eating habits and weight. Continue taking your medication exactly as prescribed and contact your healthcare provider if you have concerns.
References
- Mounjaro 2.5 mg KwikPen — UK patient information leaflet
- NICE: Information about tirzepatide (TA1026)