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
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Latest Weight Loss News & What It Means for UK Adults
Weight loss continues to be a major focus of UK health policy and medical research. Recent developments in prescription weight management, including new GLP-1 medications, have changed the landscape for adults seeking professional support. This guide covers the latest news on weight management in the UK, what's available on the NHS, and how new treatments like Mounjaro and Wegovy are changing weight loss options for eligible adults. Whether you're exploring weight management through your GP or considering prescription options, understanding the current picture is essential.
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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.
Recent Developments in Prescription Weight Loss
The most significant recent development in weight loss medication is the approval and availability of GLP-1 receptor agonist injections for weight management in the UK. Wegovy (semaglutide) and Mounjaro (tirzepatide) are now licensed for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or heart disease.
Clinical trial data has been substantial: Wegovy showed average weight loss of approximately 15% of body weight in the STEP trials, whilst Mounjaro demonstrated weight loss ranging from 15% to 21% depending on dose in the SURMOUNT trials. However, individual results vary significantly, and these medications work alongside a reduced-calorie diet and increased physical activity, not as replacements for lifestyle changes.
The key point: both are prescription-only medicines requiring clinical assessment before being prescribed. They're not available over the counter, and not all patients will be eligible or suitable candidates.
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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.
NHS Weight Loss Support & Access Routes
The NHS weight loss pathway is structured in four tiers. Tier 1 includes community support and digital tools like MyWeightCheck's free BMI calculator and weight converter. Tier 2 involves GP-led behaviour change programmes. Tier 3 is specialist weight management services where prescription medications like Mounjaro or Wegovy may be offered following clinical assessment. Tier 4 covers bariatric surgery for severe cases.
Access to prescription weight loss medication through the NHS is currently through tier 3 specialist services, and availability varies by region. Many areas have significant waiting lists. Private prescription options are also available through online consultations with UK-licensed prescribers, offering quicker access but at individual cost. Your GP can advise on NHS pathways in your area.
- 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.
Are GLP-1 weight loss injections available on the NHS?
Yes, but availability is through specialist tier 3 weight management services, not standard GP prescriptions. You'd typically need a GP referral. Waiting times vary by region. Private prescription through online consultations is also available but involves individual cost.
How much weight can you lose with Wegovy or Mounjaro?
Clinical trials showed average weight loss of 15% with Wegovy and 15–21% with Mounjaro, depending on dose. However, individual results vary significantly. Weight loss also depends on diet, activity level, and how long you take the medication. Always expect variation.
What's the difference between Ozempic and Wegovy?
Both contain semaglutide, but Ozempic is licensed for type 2 diabetes (up to 2mg dose). Wegovy is the weight management version (up to 2.4mg). Ozempic is not licensed for weight loss in the UK, though it may be prescribed off-label. Wegovy is the approved choice for weight management.
Do I need to change my diet and exercise with weight loss injections?
Yes, absolutely. GLP-1 medications like Wegovy and Mounjaro are prescribed alongside reduced-calorie diet and increased physical activity. They support your efforts by reducing appetite and cravings, but lifestyle changes are essential for sustained weight loss.
How do I check if I'm eligible for prescription weight loss treatment?
Eligibility starts at BMI 30 or above, or BMI 27–29.9 with weight-related health conditions. Your GP can assess this or you can use our free BMI calculator on this page to check your current BMI and discuss options with your healthcare provider.
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.