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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Weight Loss Medication News — What's Available in the UK
Weight loss medication has become a significant topic in UK health news, with prescription options like Mounjaro and Wegovy now available for eligible adults. If you're considering prescription weight management in the UK, it's important to understand what's available, who qualifies, and how the NHS and private pathways differ. This guide covers the latest medication options, clinical evidence, and practical steps to find out if you're eligible for prescription weight loss support.
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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-Licensed Weight Loss Medications — Your Options
Three prescription medications are currently licensed for weight management in the UK. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, administered as a once-weekly injection. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks alongside diet and activity changes. Wegovy (semaglutide) is a GLP-1 receptor agonist, also given once weekly, with clinical trial data showing approximately 15% average weight loss. Saxenda (liraglutide) is a daily injection, offering similar mechanisms but requiring daily dosing.
All three are prescription-only medicines requiring a clinical assessment before being prescribed. Eligibility typically includes adults with a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply due to higher health risks at the same BMI level. Use our free BMI calculator above to check where you currently sit on the BMI scale.
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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 Access vs Private Routes — Finding Your Pathway
In the UK, prescription weight loss medication is accessed through two routes. The NHS route involves referral from your GP to a specialist tier 3 weight management service, typically in larger NHS trusts. Availability and waiting times vary significantly by region—some areas have waiting lists extending months or years. The private route involves an online consultation with a UK-licensed prescriber, following which a prescription can be issued and dispensed by a GPhC-registered pharmacy. This is typically faster but involves direct costs.
If you're interested in exploring whether medication support is right for you, start by speaking with your GP about your weight management goals. They can assess your individual health situation, discuss the NHS pathway, or signpost you to private options. Track your current health metrics using our free progress tracker and BMI calculator to have concrete information for that conversation.
- 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 weight loss medication available on the NHS in the UK?
Yes. Tirzepatide (Mounjaro) and semaglutide (Wegovy) are now approved for NHS use in specialist tier 3 weight management services. However, access varies considerably by region and ICB. Your GP can refer you to your local specialist service, though waiting lists can be lengthy. Private options are also available via online prescription services.
Who is eligible for weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, hypertension, sleep apnoea, cardiovascular disease) may be eligible. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds apply. A prescriber will assess your individual circumstances.
How much weight can I expect to lose with prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight over 72 weeks with Mounjaro, and approximately 15% with Wegovy, alongside diet and activity changes. Individual results vary significantly. Weight loss is not assured and depends on adherence, lifestyle changes, and personal factors.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with higher average weight loss (15–21%) in trials. Wegovy (semaglutide) is a single GLP-1 agonist with approximately 15% average weight loss. Both are once-weekly injections. Your prescriber will advise which is more suitable.
How do I start the conversation about weight loss medication with my GP?
Book an appointment and discuss your weight management goals, any weight-related health conditions, and interest in medication support. Bring your BMI and current health metrics—use our free BMI calculator to prepare. Your GP can assess eligibility and discuss both NHS and private pathways with you.
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.