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
Free tracker included with every download this week
Understanding Ozempic Starting Dose and Weight Loss in the UK
Ozempic contains semaglutide but is NOT licensed for weight loss in the UK — it's approved only for type 2 diabetes management. If you're looking for prescription weight loss medication, Wegovy (also semaglutide, but at a higher dose) is the licensed option. Understanding the difference between these medications, their starting doses, and how GLP-1 weight loss works is essential for making informed decisions about weight management in the UK. This guide clarifies the facts and explains your actual options for prescription weight loss treatment through the NHS or private channels.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Ozempic vs Wegovy: Why the Confusion?
Both Ozempic and Wegovy contain the same active ingredient: semaglutide. However, they are licensed for different purposes in the UK and use different doses:
- Ozempic: Approved for type 2 diabetes. Maximum dose is 2 mg once weekly. Not licensed for weight loss.
- Wegovy: Approved specifically for weight management in UK adults. Maximum dose is 2.4 mg once weekly.
Using Ozempic for weight loss would be off-label use — meaning it's prescribed for a purpose outside its licensed indication. In the UK, the licensed choice for weight management is Wegovy. Additionally, our GLP-1 weight loss calculator can help you understand potential outcomes with approved weight management medications.
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.
Wegovy Starting Dose and Escalation Schedule
If you're prescribed Wegovy for weight management, the starting dose is 0.25 mg once weekly. This low dose helps minimise side effects as your body adjusts. The dose then escalates every 4 weeks:
- Weeks 1–4: 0.25 mg
- Weeks 5–8: 0.5 mg
- Weeks 9–12: 1 mg
- Weeks 13–16: 1.7 mg
- Week 17+: 2.4 mg (maintenance)
Your prescriber may adjust this schedule based on your tolerance and response. Clinical trials showed Wegovy helps participants lose an average of 15% body weight, though results vary individually. Use our BMI calculator to establish your baseline before starting 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.
Is Ozempic ever prescribed for weight loss in the UK?
Ozempic is not licensed for weight loss in the UK. Using it for weight loss is off-label and not recommended. Wegovy is the licensed semaglutide option for weight management. Always discuss with your GP or prescriber which medication is appropriate for your situation.
What's the difference between Ozempic and Wegovy?
Both contain semaglutide but serve different purposes. Ozempic (up to 2 mg) treats type 2 diabetes. Wegovy (up to 2.4 mg) is licensed for weight management. They use different starting doses and escalation schedules. In the UK, Wegovy is the correct choice for weight loss.
Can I access Wegovy on the NHS?
Access to Wegovy through the NHS is through specialist tier 3 weight management services, typically after GP referral. Availability varies significantly by region and waiting lists can be lengthy. Private prescribing is also available through registered UK pharmacies and online prescribers.
What side effects might I experience when starting Wegovy?
Common starting dose side effects include nausea, mild diarrhoea, and reduced appetite — usually temporary. Serious side effects are rare but include severe stomach pain (possible pancreatitis) or allergic reactions. Report any concerning symptoms to your prescriber immediately.
How much weight can I expect to lose with Wegovy?
Clinical trials showed an average weight loss of around 15% of body weight over 68 weeks at the maximum 2.4 mg dose. Individual results vary significantly. Weight loss requires Wegovy alongside a reduced-calorie diet and increased physical activity — medication alone is not sufficient.
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.