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 Mounjari? UK Weight Management Information
Mounjari is not a licensed weight management medication in the UK. You may have encountered this term while researching weight loss options, but it's important to understand what prescription treatments are actually available through the NHS and private prescribers in the UK. If you're looking for information about weight loss injections, GLP-1 medications, or healthy weight management strategies, MyWeightCheck provides free tools and guidance aligned with NHS health advice to help you understand your options and make informed decisions about your health.
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Calculate Your BMI Instantly
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.
Licensed Weight Loss Medications in the UK
The UK has two main prescription-only weight management injections currently licensed: Mounjaro (tirzepatide) and Wegovy (semaglutide). Both are approved by the MHRA and available through NHS specialist weight management services or private prescribing following a clinical assessment.
- Mounjaro: A dual GIP and GLP-1 receptor agonist, dosed at 2.5mg to 15mg once weekly. Clinical trials showed average weight loss of 15–21% of body weight.
- Wegovy: A GLP-1 receptor agonist, dosed at 0.25mg to 2.4mg once weekly. STEP trials demonstrated average weight loss of approximately 15% of body weight.
- Saxenda: An older GLP-1 medication (liraglutide), given as a daily injection rather than weekly.
All three require a prescription from a UK-licensed prescriber following a clinical assessment to confirm eligibility and safety.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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 medication, you have two main routes in the UK. NHS route: Ask your GP for a referral to your local tier 3 specialist weight management service. Availability and waiting times vary significantly by region. Private route: Access prescription weight loss treatment through GPhC-registered online prescribing services following a remote clinical assessment.
Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Use our free BMI calculator above to check your personal BMI, and our GLP-1 weight loss calculator to estimate potential weight loss with these medications. Always consult your GP for personalised advice.
- 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.
Is Mounjari available in the UK?
Mounjari is not a licensed weight management medication in the UK. You may be thinking of Mounjaro (tirzepatide), which is licensed and available through NHS specialist services and private prescribing. If you've seen "Mounjari" mentioned online, it may be a misspelling or reference to a medication not approved in the UK market.
What's the difference between Mounjaro and Wegovy?
Both are prescription-only weight loss injections licensed in the UK, but they work differently. Mounjaro is a dual GIP and GLP-1 agonist (maximum 15mg weekly), while Wegovy is a GLP-1 agonist only (maximum 2.4mg weekly). Clinical trials showed similar average weight loss outcomes (15–21%), though individual results vary significantly.
Can I get weight loss injections on the NHS?
Yes, prescription weight loss medications including Mounjaro and Wegovy are available through NHS tier 3 specialist weight management services. You'll need a GP referral and will be assessed for eligibility. Waiting times vary by region — some areas have significant delays. Private prescribing is also available for faster access.
What's the healthy weight range for my height?
Your healthy weight range depends on your height and is based on a BMI of 18.5 to 24.9 (or 18.5 to 22.9 for South Asian, Chinese, Black African, or Black Caribbean adults). Use our free BMI calculator on this page to find your personal healthy weight range and check your current BMI status.
How much weight can I expect to lose with GLP-1 medication?
Clinical trials show average weight loss of 15–21% of body weight with prescription GLP-1 medications, but individual results vary significantly. Weight loss depends on your starting weight, dose, diet, activity level, and how your body responds. Our free GLP-1 weight loss calculator can help you estimate potential outcomes based on different doses.
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.