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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Weight Loss Templates — UK Prescription Medication Guide
If you're looking for weight loss templates or structured approaches to weight management in the UK, prescription medication may be an option worth exploring with your GP. This guide covers the UK-licensed weight loss medications available, who is eligible, and how the NHS and private routes work differently. Weight management in the UK now includes several evidence-based prescription options alongside traditional diet and exercise approaches. Our free BMI calculator can help you understand where you stand, and the GLP-1 weight loss calculator can show you potential results if medication is prescribed for you.
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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 Loss Medications Explained
Three prescription weight loss medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Mounjaro and Wegovy are once-weekly injections, while Saxenda is a daily injection. These are all prescription-only medicines requiring clinical assessment before being prescribed.
Mounjaro is a dual GIP and GLP-1 receptor agonist. Clinical trials (SURMOUNT-1) showed participants lost an average of 15–21% of their body weight over 72 weeks alongside a reduced-calorie diet and increased physical activity. Individual results vary significantly.
Wegovy (semaglutide) is a GLP-1 receptor agonist. The STEP-1 trial showed average weight loss of approximately 15% at the maximum dose of 2.4mg over 68 weeks with lifestyle changes.
Both work by helping reduce appetite, support feeling fuller after smaller meals, and slow gastric emptying. Important: These are not assured solutions — they work best alongside dietary changes and exercise, not instead of them.
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: Eligibility and How to Access
NHS access requires referral to a tier 3 or tier 4 specialist weight management service through your GP. NHS eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. However, NHS availability varies significantly by region — waiting lists can be very long in many areas, and not all ICBs currently commission these services.
Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. This route does not require NHS referral and is often faster, though costs vary (typically £129–£320+ per month depending on dose). Use our free progress tracker to monitor your weight loss journey once you begin treatment. Always discuss any weight loss medication template with your GP first to check for contraindications or interactions with other medicines.
- 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 Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. In clinical trials, Mounjaro showed slightly higher average weight loss (15–21%) compared to Wegovy (approximately 15%) at maximum doses. Both are once-weekly injections. Individual results vary, and the best choice depends on your personal health profile and GP assessment.
How do I know if I'm eligible for prescription weight loss medication in the UK?
Generally, you may be eligible if you have a BMI of 30 or above, or 27–29.9 with at least one weight-related health condition (type 2 diabetes, high blood pressure, sleep apnoea, cardiovascular disease, or abnormal blood fats). Use our free BMI calculator to check your starting point, then discuss eligibility with your GP. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds apply.
Can I get weight loss medication on the NHS?
Yes, Mounjaro and Wegovy are now approved on the NHS through specialist tier 3 weight management services. However, access varies by region. You'll need referral from your GP. Waiting lists can be long. Private access through GPhC-registered pharmacies is often faster but involves private costs. Ask your GP about availability in your area.
How much weight can I expect to lose with these medications?
Clinical trials showed average weight loss of 15–21% of body weight over several months (depending on the drug and dose) when combined with a reduced-calorie diet and increased physical activity. However, results vary significantly between individuals — some lose more, some less. Our GLP-1 weight loss calculator can help you explore projected outcomes. These medications are tools to support weight management, not assured solutions.
Are there side effects I should know about?
Common side effects include nausea, diarrhoea, vomiting, and constipation — often mild and temporary, improving as your body adjusts. Serious side effects are rare but can include severe stomach pain (possible pancreatitis) and gallbladder issues. Always discuss side effect concerns with your prescriber. Your GP or online prescriber will review contraindications before prescribing.
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.