Mounjaro (Tirzepatide) for Weight Management: A Pharmacist’s Clinical Explanation of the Evidence, the Eligibility Criteria, and the Realistic Expectations

Reviewed by GPhC Pharmacist at Priory Pharmacy, York

Mounjaro is the brand name for tirzepatide in the UK. The MHRA approved it in late 2023 for weight management. It’s for adults with obesity, or who are overweight with at least one weight-related health condition.

Since approval, Mounjaro has become the most talked-about weight loss medicine in the UK. Two things drove this:

• Strong results from the SURMOUNT clinical trials, showing average weight loss of up to 22.5% of body weight
• Growing awareness among patients and in the media

At Priory Pharmacy in York, we offer Mounjaro as part of a structured weight management programme. A clinical team supervises you throughout. This article covers:

• How the medicine works
• Who can have it
• What results to realistically expect
• What our supervised programme involves

How Is Mounjaro Different From Other GLP-1 Medicines?

Tirzepatide works on two hormone systems at once. This is called a “dual” mechanism.

• GLP-1 receptor: This reduces appetite and slows down how fast your stomach empties.
• GIP receptor: This is the new part. It’s not found in older medicines like semaglutide (Wegovy). It seems to boost appetite suppression, improve metabolism, and may affect how the body stores fat.

What this means in practice: because Mounjaro works on both systems, it tends to produce more weight loss than GLP-1-only medicines. This is especially true at the higher doses (10 mg and 15 mg). Trial data supports this. It’s seen as a real step forward in weight-loss treatment.

What Does the SURMOUNT Trial Data Actually Show?

The SURMOUNT-1 trial is the main clinical study behind Mounjaro’s use for weight loss.

Trial basics:

• Participants had obesity (BMI of 30 or above)
• None had type 2 diabetes
• The trial ran for 72 weeks

Results at the highest dose (15 mg):

• Average weight loss: 22.5% of body weight
• 91% of people lost at least 5% of their body weight
• 57% of people lost at least 20% of their body weight

Important context: these numbers are averages from a trial. Real-world results vary a lot from person to person. Your results depend on:

• Genetics
• Diet
• Physical activity levels
• Existing health conditions
• How well you tolerate the medicine

Some people will do better than the trial average. Some will do less well. Think of the trial data as showing what’s possible not a guarantee for any one person.

Who Can Have Mounjaro at Priory Pharmacy in York?

Eligibility follows MHRA guidance and UK prescribing rules. Before starting treatment, our prescribers carry out a full clinical check.

You may be able to have Mounjaro if you meet all of these:

• Your BMI is 30 or above. Or, your BMI is 27 or above and you have a weight-related health condition for example, high blood pressure, type 2 diabetes, high cholesterol, sleep apnea, or heart disease
• You have no reason you can’t take a GLP-1 or GIP medicine
• You are not pregnant, and not planning to become pregnant during treatment
• You and your family have no history of a specific thyroid cancer (medullary thyroid carcinoma) or a condition called MEN 2
• You have no history of severe gut disease, such as severe gastroparesis or active inflammatory bowel disease
• You have no recent history of pancreatitis

We also check all your current medicines, including the contraceptive pill, to spot any interactions. We’ll talk to you about past attempts at weight loss, and about your current diet and lifestyle. This happens at your first consultation.

Understanding the Dosing Schedule

You start Mounjaro at a low dose: 2.5 mg, once a week. It’s a small injection under the skin — into your stomach area, thigh, or upper arm.

How the dose increases:

• The dose goes up by 2.5 mg every 4 weeks
• You’ll reach a target dose of 5 mg, 10 mg, or 15 mg
• Your exact target depends on how you respond and how well you tolerate it

Why the slow increase matters: going up too fast raises the risk of stomach-related side effects. These side effects are the most common reason people stop treatment. A gradual increase helps your body adjust.

Mounjaro Works Best as Part of a Full Programme

Mounjaro isn’t designed to be used on its own. It works best alongside:

• Diet support
• Guidance on physical activity
• Regular check-ins with a clinician

At Priory Pharmacy in York, our programme includes:

• Follow-up consultations throughout your treatment
• Monitoring your progress
• Managing any side effects
• Adjusting your dose when needed
• Ongoing clinical support to help you get the best results

Medicine alone doesn’t fix the underlying causes of weight gain. Lasting results come from combining the medicine with lifestyle changes with proper clinical support along the way.

This article gives general information. It is not personal medical advice. To talk about Mounjaro or other weight management options at Priory Pharmacy in York, please book a consultation with our clinical team.