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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Semaglutide Weight Loss Dosage Chart — UK Guide
Semaglutide is a GLP-1 receptor agonist available in the UK as Wegovy for weight management. It's prescribed as a once-weekly injection that starts at a low dose and gradually increases over several months. This guide explains the full semaglutide weight loss dosage chart used in the UK, how the dose progression works, expected timelines, and what clinical evidence shows about effectiveness. Wegovy is prescription-only and requires a clinical assessment before being prescribed.
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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.
Wegovy Semaglutide Dose Progression Schedule
Wegovy (semaglutide 2.4 mg) uses a structured dose escalation schedule over 17+ weeks. The dosing follows a step-by-step progression to allow your body to adapt and reduce side effects. Each dose is injected once weekly using a pre-filled pen.
- Weeks 1–4: 0.25 mg — Starting dose (adjustment phase)
- Weeks 5–8: 0.5 mg — First escalation
- Weeks 9–12: 1 mg — Second escalation
- Weeks 13–16: 1.7 mg — Third escalation
- Week 17+: 2.4 mg — Maintenance/maximum dose
The dose is increased every 4 weeks if tolerated. Your prescriber may keep you on a lower dose if you experience side effects or have specific health conditions. This gradual approach, known as dose titration, helps your body adjust to the medication while minimising nausea and gastrointestinal effects.
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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.
Semaglutide Weight Loss Results and Clinical Evidence
Clinical trials (STEP-1) showed that participants taking semaglutide 2.4 mg averaged approximately clinically studied weight loss over 68 weeks, alongside a reduced-calorie diet and increased physical activity. Individual results vary significantly — some people lose more, some less. The weekly weight loss injection works by reducing appetite and increasing feelings of fullness, slowing how food moves through your stomach.
To estimate your potential weight loss with different doses, use our free GLP-1 weight loss calculator above. Your progress depends on your starting weight, diet, exercise, and individual response to the medication. Track your journey using our free progress tracker to monitor changes over weeks and months of treatment.
- 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 Wegovy and Ozempic semaglutide dosage?
Both contain semaglutide, but Ozempic (for type 2 diabetes) uses doses up to 2 mg. Wegovy (for weight loss) escalates to 2.4 mg maximum. Ozempic is not licensed for weight loss in the UK — Wegovy is the licensed weight management version.
How long does it take to reach the 2.4mg dose?
Approximately 17 weeks. You start at 0.25 mg and increase every 4 weeks: 0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg. Your prescriber may adjust this timeline based on tolerability and side effects.
Can I skip doses or inject more frequently?
No. Wegovy must be injected once weekly — never more frequently. If you miss a dose within 4 days, inject as soon as remembered. If more than 4 days have passed, skip that dose and continue your normal schedule.
Will I lose weight at every dose level?
Weight loss typically begins at the starting dose and increases gradually with higher doses. The 2.4 mg dose showed the most significant weight loss in clinical trials, but results vary. Your GP can discuss expected outcomes based on your individual circumstances.
Is semaglutide 2.4mg the highest dose available?
Yes, 2.4 mg is the maximum licensed dose for Wegovy in the UK. Your prescriber will not increase beyond this dose. If you reach 2.4 mg, you continue this dose as your maintenance treatment.
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.