The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
Free tracker included with every download this week
What is Monjour?
Monjour is not currently a recognised weight management medication in the UK. You may be searching for Mounjaro (tirzepatide) or Wegovy (semaglutide), which are prescription-only GLP-1 and GIP/GLP-1 receptor agonist injections licensed for weight management in UK adults. Both are administered once weekly and work by helping to regulate appetite and support feeling fuller after meals. If you're exploring weight loss options in the UK, it's important to understand what medications are actually available and how they work. This guide clarifies the difference and helps you find accurate health information about prescription weight management treatments available through NHS specialist services or private prescribing.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
UK Weight Management Medications Explained
If you've heard about "Monjour" and are looking for weight loss information, you may have encountered a misspelling or alternative name. The two main UK-licensed prescription injections for weight management are Mounjaro (tirzepatide) and Wegovy (semaglutide). Mounjaro is a dual GIP and GLP-1 receptor agonist that activates two natural hormone pathways to help regulate appetite and food cravings. Wegovy is a GLP-1 receptor agonist that works on a single pathway. Both are prescription-only medicines requiring a clinical assessment before being prescribed. In clinical trials, Mounjaro helped participants lose an average of 15–21% of their body weight, whilst Wegovy resulted in approximately 14.9% average weight loss—though individual results vary significantly. Access in the UK is through NHS specialist weight management services or private online prescribing following a consultation with a licensed prescriber. Use our free BMI calculator above to check whether you might be eligible for these treatments based on current UK guidance.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
How to Access Weight Loss Treatment in the UK
If you're interested in prescription weight loss treatment, your first step is to speak with your GP, who can refer you to a tier 3 specialist weight management service on the NHS. Alternatively, you can access private prescribing through a licensed UK prescriber via an online consultation. Both Mounjaro and Wegovy require a clinical assessment to confirm eligibility—typically a BMI of 30 or above, or 27–29.9 with a weight-related health condition such as type 2 diabetes, high blood pressure, or sleep apnoea. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses. Remember that prescription medications work best alongside a reduced-calorie diet and increased physical activity. Always consult your GP or a qualified healthcare professional before making any health decisions about weight management treatment.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Both are prescription-only once-weekly injections. Mounjaro's dual mechanism may result in slightly higher average weight loss in clinical trials (15–21% vs 14.9%), but individual results vary. Both require clinical assessment and are available through NHS specialist services or private prescribing in the UK.
Is "Monjour" a real weight loss medication?
"Monjour" is not a recognised weight management medication in the UK. If you've encountered this term, it may be a misspelling or misremembering of Mounjaro. The two main prescription weight loss injections available in the UK are Mounjaro and Wegovy. Always verify medication names with your GP or prescriber to ensure you're discussing the correct treatment.
How much weight can I expect to lose with these medications?
Clinical trials showed average weight loss of 15–21% body weight with Mounjaro and approximately 14.9% with Wegovy—achieved alongside a reduced-calorie diet and increased physical activity. However, individual results vary significantly. Some people lose more, some less. Use our free GLP-1 weight loss calculator to see projected outcomes based on your starting weight and chosen dose.
Do I need a prescription to get these injections in the UK?
Yes, both Mounjaro and Wegovy are prescription-only medicines in the UK. You'll need a clinical assessment from a licensed prescriber to confirm eligibility based on your BMI and health conditions. Access is available through NHS specialist weight management services (tier 3) or private online prescribing services. Your GP can provide a referral to NHS services, or you can arrange a private consultation.
What's the difference between Wegovy and Ozempic?
Both contain semaglutide but are different products. Wegovy is licensed for weight management (up to 2.4 mg dose). Ozempic is licensed for type 2 diabetes management (up to 2 mg dose) and is not approved for weight loss in the UK. Using Ozempic for weight loss would be off-label. Always ask your prescriber which medication they're prescribing and confirm it's the appropriate licensed version for your treatment goal.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.