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 Boot Camp: UK Prescription Medication Options
A weight loss boot camp approach often involves intensive programmes, but for many UK adults, prescription medication offers a clinically-proven alternative or complement to traditional weight management. If you're interested in weight loss medication in the UK, there are several licensed options available through both NHS and private routes. This guide covers UK-licensed prescription weight loss treatments, eligibility criteria, and how to explore whether medication might support your weight management journey alongside lifestyle changes.
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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.
UK-Licensed Prescription Weight Loss Medications
Three prescription-only medicines are licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Mounjaro and Wegovy are once-weekly injections, while Saxenda is a daily injection. All work by activating GLP-1 hormone pathways to help reduce appetite and support feeling fuller after smaller meals.
In clinical trials, these medications helped participants lose an average of 15–21% of their body weight when combined with reduced-calorie diet and increased physical activity. Individual results vary significantly — some people experience greater weight loss, others more modest results. These are prescription-only medicines requiring a clinical assessment before being prescribed, and they're typically used alongside, not instead of, lifestyle changes.
Eligibility generally includes adults with a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Use our free BMI calculator above to check your starting point, and discuss with your GP whether prescription weight loss medication might be appropriate for you.
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.
NHS vs Private Access in the UK
NHS access is through specialist tier 3 or tier 4 weight management services, typically following GP referral. Availability and waiting times vary significantly by region — some areas have long waiting lists, while others have limited provision. Private access is available through online clinical assessment with a UK-licensed prescriber, without needing NHS referral.
Regardless of route, a prescriber will assess your individual health, medical history, and eligibility before issuing a prescription. If you're interested in exploring weight loss medication, start a conversation with your GP. They can discuss NHS options in your area, assess your suitability, or refer you to specialist services. Our GLP-1 weight loss calculator can help you explore potential outcomes with different medications at various doses.
- 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's the difference between a weight loss boot camp and prescription medication?
A traditional weight loss boot camp is an intensive in-person programme combining exercise, diet coaching, and behaviour change support. Prescription medications like Mounjaro and Wegovy work differently — they're injections that reduce appetite and help you feel fuller, used alongside diet and activity changes. Many people benefit most from combining both approaches: structured lifestyle support plus medication if eligible.
Am I eligible for weight loss medication on the NHS in the UK?
Generally, yes, if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes or high blood pressure. However, NHS provision varies by region. Contact your GP to discuss eligibility in your area and whether referral to specialist weight management services is appropriate for you.
How much weight can I expect to lose with prescription medication?
Clinical trials show average weight loss of 15–21% of body weight over 68–72 weeks when medication is combined with a reduced-calorie diet and increased physical activity. However, individual results vary — some people lose more, others less. Your prescriber can discuss realistic expectations based on your personal situation.
Is prescription weight loss medication the same as a weight loss boot camp diet?
No. Medication works on appetite hormones, while boot camp diets focus on structured eating and exercise. Prescription medications like Mounjaro and Wegovy may make it easier to stick to a calorie deficit because they reduce hunger, but they work best alongside diet and lifestyle changes — not as a replacement.
How do I access prescription weight loss medication privately in the UK?
You can access weight loss medication through a private online consultation with a UK-licensed prescriber. Following assessment, if suitable, a prescription is issued and dispensed by a GPhC-registered pharmacy. This route doesn't require NHS referral but does involve private costs. Always ensure you use a registered service and qualified prescriber.
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.