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
What Are Type 2 Injections for Weight Management?
Type 2 injections refer to GLP-1 receptor agonist medications prescribed for weight management in UK adults, particularly those with type 2 diabetes or weight-related health conditions. These prescription-only injections work by mimicking natural hormones that regulate appetite and blood sugar. The most commonly prescribed options in the UK are Wegovy (semaglutide) and Mounjaro (tirzepatide), both available once weekly. They are used alongside a reduced-calorie diet and increased physical activity as part of comprehensive NHS health guidance for sustainable weight management.
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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.
How GLP-1 Type 2 Injections Work
GLP-1 medications activate the glucagon-like peptide-1 pathway, a natural hormone system in your gut that regulates appetite and blood sugar control. When you take a GLP-1 injection, it signals to your brain that you are fuller after smaller meals, reducing food cravings and overall calorie intake.
- Slows how quickly food leaves your stomach (gastric emptying)
- Helps regulate blood sugar levels more effectively
- May improve cardiovascular health markers
- Supports sustainable weight management when combined with lifestyle changes
Clinical trials have shown that GLP-1 medications help participants lose an average of 14–21% of their body weight over 68 weeks, though individual results vary significantly. These injections are prescription-only and require a clinical assessment from a UK-licensed prescriber or NHS specialist service to determine if they are suitable for your personal health profile.
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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.
UK Eligibility and How to Access Type 2 Injections
In the UK, GLP-1 medications may be prescribed to adults with a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Use our free BMI calculator above to check your personal BMI instantly.
Access is available through two routes: NHS specialist tier 3/4 weight management services (following a GP referral) or private online prescribing from a GPhC-registered pharmacy. NHS access varies by region and may involve waiting lists. Private prescribers assess eligibility online and can dispense medication if clinically appropriate. Your GP can provide NHS health advice about which route suits your situation.
You can also use our free weight converter to track your progress in your preferred units (kg, stone, lbs), and our GLP-1 weight loss calculator may help you estimate potential outcomes at different doses. Remember that prescription medications work best when combined with dietary changes, physical activity, and behavioural support — weight management is a long-term commitment.
- 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 for type 2 diabetes?
Both contain semaglutide but are licensed for different purposes. Ozempic is approved for type 2 diabetes management (doses up to 2mg). Wegovy is the licensed weight management version with higher doses up to 2.4mg. Ozempic is NOT licensed for weight loss in the UK — using it for weight loss is off-label. Wegovy is the correct prescription option for weight management.
How long does it take to see weight loss results with type 2 injections?
Most people notice changes within 4–8 weeks as doses increase, though individual timelines vary. Clinical trials showed average weight loss of 14–21% over 68 weeks at maximum dose. Results depend on dose, diet, physical activity, and individual metabolism. Your prescriber can discuss realistic timelines for your personal situation.
Are type 2 injections safe for long-term use?
GLP-1 medications have been used safely for diabetes management for many years. Weight management trials have shown good safety profiles, though side effects like nausea and constipation are common initially. They require prescription and ongoing medical monitoring. Always inform your GP of any concerns.
Can I get type 2 injections through the NHS in the UK?
Yes. NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for NHS use through specialist tier 3/4 weight management services. Access requires a GP referral and varies significantly by region. Many areas have long waiting lists. Your GP can discuss local availability and eligibility.
What happens when I stop taking type 2 injections?
Weight loss typically stabilises but may gradually return if lifestyle changes (diet and exercise) are not maintained. These injections are tools to support long-term weight management, not permanent solutions. Stopping should be discussed with your prescriber. Continuing healthy habits helps maintain progress achieved.
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.