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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Ozempic 1mg for Weight Loss in the UK
Ozempic (semaglutide) is a prescription medication approved in the UK for type 2 diabetes management, though it's sometimes used off-label for weight loss. However, the UK has other licensed prescription weight management options that may be more appropriate. If you're interested in prescription weight loss medication, it's important to understand what's available through the NHS, how eligibility works, and what the evidence shows. This guide explains your options and how to start a conversation with your GP about weight management support.
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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.
UK-Licensed Weight Management Medications
The UK has three prescription medications specifically licensed for weight management: Wegovy (semaglutide 2.4 mg), Mounjaro (tirzepatide), and Saxenda (liraglutide). These are the approved options for eligible adults seeking prescription weight loss injections in the UK.
- Wegovy — once-weekly GLP-1 injection, maximum dose 2.4 mg, average weight loss 15% body weight in clinical trials
- Mounjaro — once-weekly dual GIP/GLP-1 injection, maximum dose 15 mg, average weight loss up to 21% body weight
- Saxenda — daily GLP-1 injection, maximum dose 3 mg, average weight loss around 5-10% body weight
While Ozempic (1 mg or 2 mg semaglutide) is licensed for diabetes, Wegovy is the licensed version for weight management and is available in the UK through NHS specialist services or private prescribers. Use our GLP-1 weight loss calculator to explore projected outcomes with different 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.
NHS vs Private Access — How to Get Started
Access to prescription weight loss medication in the UK differs between NHS and private routes. NHS access is through specialist tier 3 weight management services, typically following a GP referral. Availability and waiting times vary significantly by region. Private access is available through online prescribing services following a clinical assessment, without NHS referral.
To find out if you're eligible, calculate your BMI using our free BMI calculator above. Adults with a BMI of 30 or above, or 27+ with weight-related health conditions (diabetes, high blood pressure, sleep apnoea), may qualify. Start by speaking with your GP about prescription weight management options — they can assess your individual health and discuss what's available to you locally.
- 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.
Can I use Ozempic 1mg for weight loss in the UK?
Ozempic (semaglutide up to 2 mg) is licensed in the UK for type 2 diabetes, not weight loss. Using it for weight loss is off-label. The UK-licensed weight management version is Wegovy (semaglutide 2.4 mg), available through NHS specialist services or private prescribing. Your GP or prescriber can advise which is appropriate for you.
What's the difference between Ozempic and Wegovy?
Both contain semaglutide, but Ozempic is for diabetes (up to 2 mg), while Wegovy is specifically licensed for weight management (up to 2.4 mg). Wegovy is the approved choice for weight loss in the UK. They are the same medication at different purposes and doses — Wegovy is the appropriate licensed option for weight management.
How do I access prescription weight loss medication on the NHS?
Ask your GP for a referral to your local tier 3 specialist weight management service. They will assess your BMI, health conditions, and suitability for medication. Access varies by region and waiting lists can be lengthy. Private online prescribing is also available without NHS referral, following a clinical assessment.
What's the evidence for weight loss with GLP-1 injections?
Clinical trials show GLP-1 medications help adults lose an average of 15% body weight alongside diet and exercise changes — though individual results vary. Mounjaro (a dual GIP/GLP-1 medication) showed slightly higher average weight loss (up to 21%) in trials. Results depend on dose, adherence, and lifestyle changes.
What are the side effects of weight loss injections?
Common side effects include nausea, diarrhoea, constipation, and stomach pain — usually mild and improving over time. Serious side effects are rare but can include pancreatitis or gallbladder problems. Your prescriber will discuss side effects and monitor you during treatment. Always report concerning symptoms to your GP immediately.
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.