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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What Are the Other Names for Semaglutide?
Semaglutide is the active ingredient in several prescription medications, but the brand name you see depends on what the medication is approved for. In the UK, the same active ingredient is marketed as Wegovy for weight management and Ozempic for type 2 diabetes — and there's also Saxenda, a different GLP-1 medication. Understanding which name refers to which treatment is important, especially when you're researching weight loss options or diabetes management on the NHS or privately. This guide explains the different names, doses, and how each is used in UK healthcare.
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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.
Semaglutide Brand Names and Their Uses in the UK
Semaglutide is sold under two main brand names in the UK, both manufactured by Novo Nordisk. Wegovy (semaglutide 2.4 mg) is the weight management formulation and is licensed specifically for weight loss in adults with a BMI of 30 or above, or 27 or above with weight-related health conditions. Ozempic (semaglutide up to 2 mg) is the diabetes formulation and is approved for type 2 diabetes management only — it is not licensed for weight loss in the UK, though it is sometimes prescribed off-label for this purpose.
The key difference is not the active ingredient (both are semaglutide) but the dose and licensed indication. Wegovy is a weekly injection dosed up to 2.4 mg, while Ozempic is dosed up to 2 mg and is primarily a diabetes treatment. When you see "semaglutide 2.4 mg weight loss" mentioned, that refers to Wegovy specifically. A GLP-1 receptor agonist like semaglutide works by activating appetite-regulating hormones and slowing gastric emptying, which helps support weight management alongside a reduced-calorie diet and increased physical activity.
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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.
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NHS Access and Private Prescribing Routes in the UK
In the UK, accessing Wegovy (the semaglutide formulation for weight loss) depends on whether you go through the NHS or private route. NHS access is through specialist tier 3 weight management services — your GP can refer you, but these services have limited capacity and significant waiting lists vary by region. Private access is available through GPhC-registered online prescribing services following a clinical assessment; you do not need an NHS referral. Both routes require a prescription from a UK-licensed prescriber who will assess your eligibility based on BMI, health conditions, and medical history. Use our free GLP-1 weight loss calculator above to understand potential weight loss outcomes, and our BMI calculator to check whether you may meet eligibility thresholds for semaglutide 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 Wegovy the same as Ozempic?
Both contain semaglutide, but Wegovy (2.4 mg) is licensed for weight loss, while Ozempic (up to 2 mg) is licensed for type 2 diabetes. They are different products with different approved uses in the UK. Ozempic is not licensed for weight management.
What does GLP-1 receptor agonist mean?
GLP-1 receptor agonist is the drug class — it mimics the natural hormone GLP-1 that regulates appetite and blood sugar. Semaglutide is one example; another is liraglutide (Saxenda). All activate the same hormone pathway but with different potencies and formulations.
Can I get semaglutide on the NHS for weight loss?
Yes, if you meet eligibility criteria (BMI ≥30, or ≥27 with comorbidities) and are referred to a tier 3 specialist weight management service. However, NHS access is limited and waiting lists are long in many areas. Private access is faster but involves out-of-pocket costs.
What is the difference between Saxenda and Wegovy?
Both are GLP-1 medications for weight management, but Saxenda (liraglutide) is a daily injection, while Wegovy (semaglutide) is a once-weekly injection. Clinical trials show similar weight loss outcomes, though individual results vary. Your prescriber will advise which suits you.
Is semaglutide available under any other names?
In the UK, semaglutide for weight loss is only marketed as Wegovy. Internationally, it may be called by other names, but Wegovy is the UK-approved brand name for weight management. Always verify the brand name and licensed use with your prescriber.
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