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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Wegovy Weight Loss Chart — What the Evidence Shows
A Wegovy weight loss chart shows the average results from clinical trials, not assured individual outcomes. The STEP-1 trial demonstrated that participants taking semaglutide (the active ingredient in Wegovy) lost an average of around 14.9% of their body weight over 68 weeks when combined with a reduced-calorie diet and increased physical activity. Results vary significantly between individuals depending on dose, lifestyle, and personal metabolism. This guide explains what real-world Wegovy weight loss looks like in UK measurements and how to track your own progress.
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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.
Expected Weight Loss by Wegovy Dose
Wegovy is a once-weekly GLP-1 injection available in five doses: 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, and 2.4 mg (the maximum). Your prescriber will start you at the lowest dose and increase gradually every 4 weeks if tolerated.
STEP trial average results (68 weeks):
- 0.5 mg dose: approximately 4–clinically studied weight loss
- 1.0 mg dose: approximately 8–clinically studied weight loss
- 1.7 mg dose: approximately 12–clinically studied weight loss
- 2.4 mg dose (maximum): approximately clinically studied weight loss
These are clinical trial averages — individual results vary widely. Some people lose more, some less. Weight loss also depends on diet, exercise, baseline weight, and how your body responds to the medication. This weekly weight loss injection works best alongside sustained lifestyle changes, not as a replacement for them.
Clinically BackedWeight Loss
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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.
Tracking Your Actual Weight Loss Progress
A personal weight loss chart is more useful than clinical trial averages because it shows your actual progress over time. Track your weight weekly at the same time of day (ideally in the morning before eating) and record it in a spreadsheet or use our free progress tracker to visualise your journey.
What to expect: Weight loss is rarely linear — you may lose steadily for 2–3 weeks, then plateau for a week or two before dropping again. This is normal. Wegovy eligibility in the UK requires a BMI of 30 or above, or 27 or above with weight-related health conditions. Use our free BMI calculator to check your starting point, then track changes monthly. Most people on Wegovy see noticeable progress within 8–12 weeks at their maintenance dose.
- 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.
How quickly does Wegovy cause weight loss?
Weight loss typically becomes noticeable within 4–8 weeks once you reach your maintenance dose (usually 1.7 mg or 2.4 mg). The first 4 weeks at starter doses (0.25–0.5 mg) focus on tolerance. Consistent weight loss usually accelerates weeks 9–20. Individual timelines vary significantly.
Can I use a weight loss chart to predict my personal Wegovy results?
Clinical trial charts show averages only — they cannot predict individual outcomes. Factors like your starting weight, diet adherence, exercise level, age, and metabolism all affect personal results. Your own weekly tracking chart is far more useful than population averages.
What's the difference between Wegovy and Ozempic weight loss?
Both contain semaglutide, but Ozempic is licensed for type 2 diabetes (doses up to 2 mg) and is not approved for weight loss in the UK. Wegovy is specifically licensed for weight management (doses up to 2.4 mg). Using Ozempic for weight loss is off-label. Always use the medication prescribed to you by your GP or prescriber.
Is Wegovy weight loss permanent after stopping?
Weight loss is sustainable only while taking Wegovy and maintaining lifestyle changes. Clinical evidence shows most weight returns after stopping if diet and exercise habits don't change. Wegovy is designed as ongoing treatment, not a short-term fix. Discuss long-term plans with your prescriber.
How does Wegovy compare to Mounjaro for weight loss?
Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist — it activates two hormone pathways, while Wegovy (semaglutide) activates one. STEP trial data showed Wegovy at 2.4 mg achieved ~14.9% average weight loss; SURMOUNT trial data showed Mounjaro at 15 mg achieved ~20.9% average weight loss. Results vary individually. Your prescriber will recommend the most suitable option 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.