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 Quote — What It Means for UK Weight Management
A "weight loss quote" typically refers to an estimate of how much weight you might lose using a specific weight loss medication or programme. In the UK, prescription weight loss medications like Mounjaro and Wegovy can help eligible adults lose weight alongside lifestyle changes. Clinical trials show these medications support meaningful weight loss, though individual results vary significantly. Your GP or a licensed prescriber will assess your eligibility based on your BMI, health conditions, and personal circumstances. Understanding what realistic weight loss looks like is important for setting sustainable health goals.
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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 — What the Evidence Shows
Three prescription-only weight loss injections are currently licensed in the UK for weight management in eligible adults:
- Mounjaro (tirzepatide) — dual GIP and GLP-1 injection. Clinical trials showed participants lost an average of 15–21% body weight over 72 weeks alongside reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — GLP-1 injection. Average weight loss in clinical trials was approximately 15% body weight at the maximum dose.
- Saxenda (liraglutide) — daily GLP-1 injection. Supports modest weight loss, typically 5–10% body weight.
These medications work by reducing appetite, helping you feel fuller after smaller meals, and supporting better food choices. All three are prescription-only, meaning you need a clinical assessment from a licensed prescriber before starting. Individual results vary — some people lose more, some less, and some may not lose significant weight.
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 — How to Find Out If You're Eligible
In the UK, access to prescription weight loss medication is available through two routes. NHS access is through specialist tier 3 weight management services — typically requiring a referral from your GP and assessment by a specialist team. Availability varies significantly by region, and waiting times can be several months. Private access is through online consultations with UK-licensed prescribers, followed by dispensing through a GPhC-registered pharmacy — no NHS referral needed.
To find out if you're eligible, start by calculating your BMI using our free BMI calculator above. You're typically eligible if your BMI is 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, or Black Caribbean adults may qualify at lower BMI thresholds. Speak to your GP about your weight management options and what's available 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.
What does a weight loss quote actually mean?
A weight loss quote is an estimate of how much weight you might lose using a specific medication or programme. For prescription GLP-1 medications like Mounjaro and Wegovy, quotes are based on clinical trial data showing average weight loss of 15–21% of body weight. However, your personal result will depend on many factors including your starting weight, how well you follow dietary and activity recommendations, and individual response to medication. Always remember that individual results vary significantly.
Am I eligible for prescription weight loss medication in the UK?
You may be eligible if your BMI is 30 or above, or 27 or above with a weight-related health condition like type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, and Black Caribbean adults have lower eligibility thresholds (BMI 27.5+). Use our free BMI calculator to check your BMI, then speak to your GP about whether prescription weight loss treatment is suitable for you. A licensed prescriber will assess your individual circumstances.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist with an average weight loss of 15–21% in clinical trials. Wegovy (semaglutide) is a GLP-1 receptor agonist alone with average weight loss of around 15%. Mounjaro reaches its maximum dose in 20 weeks, while Wegovy takes 16 weeks. Both are once-weekly injections. Clinical evidence suggests Mounjaro may support slightly greater weight loss on average, but individual results vary. Your prescriber will recommend the most suitable option for you.
How can I access weight loss medication through the NHS?
NHS access is through specialist tier 3 weight management services. Ask your GP for a referral to your local weight management service. They will assess your eligibility and may prescribe medications like Mounjaro or Wegovy if clinically appropriate. Availability and waiting times vary significantly by region — some services have waiting lists of several months. Private access is also available through online prescribers and GPhC-registered pharmacies without an NHS referral.
What should I do if I want to explore weight loss medication options?
Start by calculating your BMI using the free BMI calculator on this page and noting any weight-related health conditions you have. Book an appointment with your GP to discuss weight management options, eligibility for prescription medication, and what's available in your area. Your GP can refer you to NHS specialist services or signpost you to private options. A licensed prescriber will then conduct a full clinical assessment before prescribing any weight loss medication.
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.