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 Wegovy 30 Units for Weight Management in the UK
Wegovy (semaglutide) is a prescription-only weight management injection licensed in the UK for adults with obesity or excess weight. While Wegovy is typically dosed up to 2.4 mg per week, the medication is often discussed in terms of "units" by patients and healthcare providers. Understanding UK dosing guidance, eligibility, and how Wegovy works alongside diet and lifestyle changes is essential for anyone considering this treatment. Always consult your GP or a licensed prescriber to determine if Wegovy is suitable for your individual health situation.
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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.
How Wegovy Works and UK Eligibility Criteria
Wegovy (semaglutide) is a GLP-1 receptor agonist — it activates a natural hormone pathway that may help reduce appetite and support feeling fuller after smaller meals. Clinically, participants in the STEP-1 trial lost an average of approximately 15% of their body weight at the maximum dose, though individual results vary significantly.
You may be eligible for Wegovy in the UK if you:
- Have a BMI of 30 kg/m² or above, OR
- Have a BMI of 27–29.9 kg/m² with at least one weight-related health condition (type 2 diabetes, high blood pressure, high cholesterol, sleep apnoea, or cardiovascular disease)
- Are an adult aged 18 or over
- Are not pregnant, planning pregnancy, or breastfeeding
Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may be eligible at lower BMI thresholds. Your prescriber will assess your individual eligibility during a clinical consultation. Use our free BMI calculator above to check your current BMI and see how it aligns with weight management criteria.
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 Dosing Schedule and What to Expect
Wegovy is injected once weekly and is gradually escalated over several weeks. Starting doses are lower (0.25 mg) and increased every 4 weeks, with the maximum therapeutic dose being 2.4 mg weekly. Weight loss typically occurs gradually — it is not immediate and requires consistency alongside a reduced-calorie diet and increased physical activity.
Common side effects include nausea, diarrhoea, vomiting, and constipation, particularly during dose escalation. Most side effects reduce over time. Serious side effects are rare but include severe stomach pain (possible pancreatitis) and serious allergic reactions.
Wegovy is prescription-only in the UK and available through NHS specialist weight management services or private online prescribing following clinical assessment. Track your progress using our free progress tracker once you begin 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 is the difference between Wegovy and Ozempic?
Both contain semaglutide, but Ozempic is licensed for type 2 diabetes (up to 2 mg) and Wegovy is licensed specifically for weight management (up to 2.4 mg). Only Wegovy is the approved weight management version in the UK. Using Ozempic for weight loss would be off-label.
How much weight can I expect to lose on Wegovy?
Clinical trials showed an average weight loss of approximately 15% of body weight at the maximum dose, though individual results vary significantly. Weight loss depends on your starting weight, adherence to medication, diet, and exercise. Results are not assured.
Is Wegovy available on the NHS in the UK?
Yes, Wegovy may be available through NHS specialist tier 3 weight management services, but access varies by region and there may be waiting lists. Alternatively, Wegovy is available privately through GPhC-registered pharmacies following an online clinical assessment with a UK-licensed prescriber.
What are the side effects of Wegovy?
Very common side effects include nausea, diarrhoea, constipation, and vomiting — especially during dose escalation. Less common side effects include headache, fatigue, and dizziness. Most side effects reduce over time. Serious side effects like severe stomach pain are rare but require immediate medical attention.
Can I use our GLP-1 weight loss calculator to estimate my results on Wegovy?
Yes — our free GLP-1 weight loss calculator can help you explore projected weight loss outcomes at different doses based on clinical trial data. Remember that individual results vary and this tool provides estimates only, not assures.
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.