Is it suitable for your weight and health?
It is commonly used in adults with a BMI of 30 or more, or 27 or more with a weight-related health condition.
Mounjaro and weight-loss injection guide.
What you need before and during treatment: how it works, dosing, nutrition, supplements, and safe management of side effects.
This guide supports education and follow-up. Your doctor determines your individual treatment plan.
Prepared and reviewed byDr Abdulaziz Mohamed Alsubaie
Consultant in Internal Medicine and Infectious Diseases
Last reviewed
July 2026
July 2026
Contact and appointments
MyClinic coordinator
For appointment coordination and enquiries, contact the clinic coordinator directly.
An important safety step
Before you start
Mounjaro is a prescription medicine. Do not start it or increase the dose yourself. Make sure your doctor knows the following.
Pregnancy and breastfeeding
It is not used for weight loss during pregnancy. Tell your doctor if you are pregnant, planning pregnancy, or breastfeeding.
Thyroid history and allergy
Tell your doctor about medullary thyroid cancer in you or your family, MEN2, or a previous allergic reaction to Mounjaro.
Stomach, pancreas, and gallbladder
Mention severe delayed stomach emptying, pancreatitis, or previous gallbladder problems before starting.
Diabetes medicines and weight-loss injections
Tell your doctor about insulin and diabetes medicines. Do not combine Mounjaro with another weight-loss injection or a medicine containing the same ingredient unless instructed.
Upcoming surgery or endoscopy
Tell the anaesthesia team that you use Mounjaro and when you took the last dose. Do not stop it on your own.
If your doctor prescribed it after reviewing these points, you can continue to dosing and injection guidance.
The simple idea
Mounjaro helps you manage hunger while you build habits
The goal is not to stop eating. It is to feel satisfied with an appropriate portion while protecting nutrition and muscle.
Fullness signals become clearer, and many people think about food less often.
Food leaves the stomach more slowly, so a large meal may feel uncomfortable.
Use this opportunity to build meals with protein, vegetables, and enough fluids.
Patient questions
Clear answers without complicated terms
Select a question for a short answer and a practical next step.
01What is Mounjaro, and how does it work?+
Mounjaro is a once-weekly injection that helps regulate appetite and blood sugar. It sends fullness signals to the brain, slows how quickly food leaves the stomach, and helps a smaller portion feel satisfying. It supports changes in eating and weight loss; it does not directly dissolve fat.
02How much weight can I expect to lose with Mounjaro?+
Results vary with dose, treatment duration, nutrition, and activity. In long-term studies, average weight loss with some doses was around 15–21% of starting body weight. At 100 kg, that is roughly 15–21 kg over the study period, not within one or two months, and it does not guarantee any individual result.
03When does it start working, and how much will I lose in the first month?+
You may notice earlier fullness within the first few weeks, but weight loss is not steady or daily. The 2.5 mg dose during the first month helps your body adjust, so do not judge treatment success after four weeks. Review average weight and waist measurement every 3–4 weeks.
04I do not feel nauseated. Does that mean Mounjaro is not working?+
No. Nausea is a side effect, not a sign of success. More useful signs are earlier fullness, smaller portions, better appetite control, and a gradual fall in average weight.
05My appetite returns before my next dose. Should I increase it?+
Hunger may increase near the end of the week, especially early in treatment. Do not increase the dose because of one day. The decision depends on your response over the whole month, your side effects, and spending at least four weeks on the current dose.
06When should I increase the dose? Must I reach 15 mg?+
Dose increases are made in 2.5 mg steps after at least four weeks, if needed and well tolerated. You do not have to reach the highest dose. The best dose is the lowest one that gives a good result with manageable side effects.
07I missed my dose. What should I do?+
If it has been four days or less, take the missed dose. If more than four days have passed, skip it and take the next dose on your usual day. Never double a dose, and keep at least three days between two doses.
08Can I change my injection day?+
Yes, as long as there are at least three days between doses. Then keep the new day. If you have stopped for a longer period, contact your doctor before restarting at your previous dose.
09Should I take Mounjaro before or after food?+
You can take it at any time of day, with or without food. Choose a day and time that are easy to remember. If your stomach is sensitive, keep meals around the injection small and light.
10My weight has stopped changing. Has the medicine stopped working?+
Not necessarily. A one- or two-week plateau is common. Compare your average weight over 3–4 weeks, and review constipation, salty foods, sleep, activity, and portion size. Menstrual-cycle changes can also temporarily affect fluid and weight. If the plateau continues, discuss the plan instead of increasing the dose yourself.
11Will I regain weight if I stop Mounjaro?+
Appetite may return and some weight may be regained after stopping, especially without a nutrition, activity, and follow-up plan. Treatment duration and the stopping plan are individual decisions with your doctor. Do not stop simply because you reached a certain number on the scale.
12Can Mounjaro cause hair loss?+
Temporary shedding may occur with rapid weight loss or low protein or iron intake, and may not be caused by the injection itself. Avoid overly rapid loss, prioritize protein, and consider blood count, iron stores, and thyroid testing according to your situation. See a dermatologist if loss is patchy, causes scarring, or persists.
13There is liquid left after the fourth dose. Can I use it?+
No. The Mounjaro multi-dose pen is designed to deliver four complete doses. The small amount visible after dose four is not a fifth dose. Do not withdraw it with a syringe.
1
After dose 1About 3 doses remain
2
After dose 2About 2 doses remain
3
After dose 3About 1 dose remains
4
After dose 4A small amount may remain, but it is not a fifth dose
14Where should I inject it? Does the site affect weight loss?+
Inject under the skin of the abdomen, thigh, or upper arm. Rotate the exact spot each week and avoid inflamed or bruised skin. Injecting in one area does not reduce fat from that area.
