Mounjaro is a new medication developed by Eli Lilly that contains the active ingredient tirzepatide. It was originally designed to help people with type 2 diabetes manage their blood sugar levels. Mounjaro is administered as a once-weekly injection using a self-injection pen, typically into the abdomen, thigh, or upper arm. In the UK, tirzepatide (Mounjaro) has been approved for use by the Medicines and Healthcare products Regulatory Agency (MHRA).
Besides helping with blood sugar, Mounjaro has also been found to be very effective at helping people lose weight. This is why you might have heard it called a "weight loss jab" in the media.
- How you take it: You inject Mounjaro once a week. Your doctor will usually start you on a small dose and slowly increase it over time. This helps your body get used to the medicine and can lower the chance of you feeling sick.
How it Works:
Mounjaro is like a "twin hormone" medicine. It acts like two natural gut hormones, GLP-1 and GIP. These hormones help control blood sugar and appetite.
- It helps your body release more insulin when needed and lowers sugar from your liver, improving blood sugar control.
- It makes you feel fuller sooner and for longer, helping you eat less.
- Working on both GLP-1 and GIP is thought to be why it can lead to greater weight loss than medicines that only use GLP-1 (like Semaglutide in Ozempic/Wegovy).
What is it Used For?
- Type 2 Diabetes: Mounjaro lowers blood sugar effectively, often helping patients reach better levels (lower HbA1c). It's used alongside diet and exercise, sometimes with other diabetes medicines, typically when standard treatments aren't enough, especially if weight loss would help.
- Weight Management: In studies, people using Mounjaro lost a significant amount of weight, often averaging 15-20% of their body weight over about 1 to 1.5 years. It's approved for adults with obesity (high BMI) or those with a lower BMI and a weight-related health problem.
Access in the UK:
- NHS: Mounjaro is available on the NHS for type 2 diabetes if you meet certain criteria. For weight loss, NHS access is starting gradually through specialist clinics for adults with a very high BMI and multiple weight related health issues.
- Private: You can also access Mounjaro privately through weight loss clinics, pharmacies or online services like ours if you meet the medical criteria. SheMed operates a weight management programme specifically tailored for women, which includes the potential prescription of GLP-1 medications such as Mounjaro and Wegovy, provided the individual meets their medical criteria.
Mounjaro vs. Semaglutide (Ozempic/Wegovy):
Both are effective weekly injections. Semaglutide works on GLP-1 while Mounjaro works on both GLP-1 and GIP. Studies suggest Mounjaro may lead to slightly more weight loss on average. But choice of drug depends on a number of factors and is very individual.
Side Effects and Safety:
Common side effects are usually mild stomach issues (nausea, vomiting, etc.) that often improve over time. Because it affects appetite, you'll feel less hungry. If you take other diabetes medicines, your doctor might adjust doses to prevent low blood sugar.
Serious side effects are rare, but contact a doctor immediately for severe tummy pain, persistent vomiting, allergic reactions, or worrying mood changes.
Important Note: Mounjaro works best with healthy eating and exercise. If you stop Mounjaro, appetite and weight can return if lifestyle changes aren't maintained.
Check our healthcare support page to see if Mounjaro could be a suitable option for you based on your health needs and the latest criteria.
FAQs
1. How is Mounjaro administered?
Mounjaro is given as a once-weekly injection. Your healthcare provider will guide you on the correct dosage and administration technique.
2. Can I use Mounjaro if I’m pregnant or breastfeeding?
No, tirzepatide is not recommended during pregnancy or breastfeeding, as its safety in these situations has not been established. If you are planning to conceive or are breastfeeding, discuss alternative options with your doctor.
3. How long does it take to see results with Mounjaro?
While individual results vary, many users begin noticing changes within a few weeks. Maximum benefits are typically observed after several months of consistent use, alongside dietary and lifestyle adjustments.
References
- MotherToBaby. (2024). Tirzepatide (Mounjaro®, Zepbound®) - Mother To Baby | Fact Sheets. https://www.ncbi.nlm.nih.gov/books/NBK605070/
- Watanabe, M., & Hasegawa, Y. (2021). Tirzepatide in adults with obesity and type 2 diabetes. New England Journal of Medicine, 385(11), 1046-1056. https://doi.org/10.1056/NEJMoa2107519
- Kahn, S. E., & Florez, J. C. (2023). Tirzepatide: A dual GLP-1 and GIP receptor agonist for type 2 diabetes management. PMC, 11543192. https://pmc.ncbi.nlm.nih.gov/articles/PMC11543192/
- Kahn, S. E., & Florez, J. C. (2023). Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine. https://pubmed.ncbi.nlm.nih.gov/36751934/
- Nauck, M. A., & Quast, D. R. (2020). Glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide: A review of their roles in obesity and type 2 diabetes. Endocrine Reviews, 41(3), 1-24. https://pubmed.ncbi.nlm.nih.gov/32459834/
- Kahn, S. E., & Florez, J. C. (2020). Tirzepatide: A novel dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist for type 2 diabetes management. Endocrine Society. https://www.ncbi.nlm.nih.gov/books/NBK605070/