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 Bootcamp: UK Prescription Medication Options
A weight loss bootcamp typically combines intensive diet, exercise, and behaviour change support — but if you're looking to accelerate results, prescription weight management medications are now available in the UK for eligible adults. This guide covers UK-licensed prescription options, how NHS weight loss medication works, who qualifies, and how to find out if prescription support is right for you. Individual results vary, and medication works best 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 Weight Loss Medications: Eligibility and Options
Three prescription-only weight loss medications are currently licensed in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Both Mounjaro and Wegovy are once-weekly injections that may help with weight management uk-wide. To be eligible, you typically need 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.
Clinical trials showed that Mounjaro helped participants lose an average of 15–21% of body weight over 72 weeks, while Wegovy achieved approximately 15% average weight loss. These results were achieved alongside reduced-calorie diets and increased physical activity — prescription weight loss uk relies on combining medication with lifestyle changes. Eligibility is assessed individually based on your health profile, BMI, and medical history. Your GP can discuss whether you might be suitable for a referral to a specialist tier 3 weight management service.
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: How to Access Weight Loss Medication in the UK
NHS access: GLP-1 weight loss injections like Mounjaro and Wegovy are available through NHS specialist weight management services, typically following a GP referral. Availability and waiting times vary significantly by region — some areas have lengthy lists. Private access: Both medications are available through GPhC-registered online pharmacies after a consultation with a UK-licensed prescriber, without needing an NHS referral.
If you're interested in exploring options, start by discussing weight management with your GP. They can assess your eligibility, discuss available support, and refer you to local services if appropriate. You can also use our free BMI calculator above to understand your current BMI category and healthy weight range, and our GLP-1 weight loss calculator to explore projected weight loss outcomes at different medication doses. Individual results vary significantly.
Next Steps: Starting Your Weight Loss Journey- 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 a weight loss bootcamp and prescription medication?
A weight loss bootcamp is an intensive short-term programme combining diet, exercise, and support. Prescription weight loss medications like Mounjaro and Wegovy support appetite regulation and are designed for longer-term use alongside lifestyle changes. Many people combine both approaches for best results.
How much weight can I expect to lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% for Mounjaro and approximately 15% for Wegovy over several months. However, individual results vary significantly based on dose, adherence, diet, and exercise. Your actual weight loss depends on many personal factors.
Am I eligible for NHS prescription weight loss medication?
You may be eligible if you have a BMI of 30 or above, or 27 or above with weight-related health conditions like diabetes or high blood pressure. Ethnicity-adjusted thresholds (lower) apply for South Asian, Chinese, Black African, and Black Caribbean adults. Ask your GP about referral to specialist weight management services.
What are the side effects of weight loss injections like Mounjaro or Wegovy?
Common side effects include nausea, diarrhoea, constipation, and stomach discomfort — these often improve over time. Seek immediate medical attention for severe stomach pain, allergic reactions, or changes in vision. Not everyone experiences side effects; your GP can discuss individual risk.
Can I get weight loss medication privately without seeing my GP first?
Yes, private prescriptions are available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. However, it's still advisable to discuss weight management with your GP first to rule out underlying health conditions and ensure medication is appropriate for 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.