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 Prepared Meals and UK Prescription Medication
Prepared meals can be a practical part of weight management, but if you're struggling to lose weight through diet alone, prescription medication may be an option. In the UK, adults with a BMI of 30 or above—or 25 to 29.9 with weight-related health conditions—may be eligible for prescription weight loss treatment. This guide covers how prepared meals fit into a weight management strategy alongside medication options available through the NHS and private prescribing. Use our free BMI calculator to check where you stand, then explore what support might be right for you.
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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.
UK-Licensed Prescription Weight Loss Options
Three prescription medications are currently licensed for weight management in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are GLP-1 and GIP receptor agonist medications that work by reducing appetite and helping you feel fuller after eating. Clinical trials have shown that people taking these medications, alongside a reduced-calorie diet and increased physical activity, lost an average of 15–21% of their body weight—though individual results vary significantly.
- Mounjaro: Dual GIP and GLP-1 agonist, once-weekly injection, doses up to 15 mg
- Wegovy: GLP-1 agonist, once-weekly injection, maximum dose 2.4 mg
- Saxenda: GLP-1 agonist, daily injection, maximum dose 3 mg
Prepared meals can complement medication by providing controlled calorie intake and reducing decision fatigue around food choices. Try our free GLP-1 weight loss calculator to estimate potential results at different doses if you're considering prescription weight loss medication.
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.
How to Access Weight Loss Medication in the UK
Access to prescription weight loss medication differs between NHS and private routes. Through the NHS, you'll be referred to a specialist tier 3 weight management service by your GP, though waiting lists vary significantly by region. Private access is available through online prescribing services where a UK-licensed prescriber assesses your eligibility via consultation—no NHS referral needed.
To find out if you qualify, calculate your BMI using our free BMI calculator above, then speak to your GP about your options. They can discuss which approach suits your situation, whether that's NHS specialist services or exploring private prescribing. Prescription weight management works best alongside lifestyle changes: prepared meals, reduced-calorie intake, and increased activity are essential for sustainable results.
- 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 prepared meals alone help me lose weight?
Prepared meals can support weight loss by controlling portions and calories, but sustainable results typically require a combination of diet, physical activity, and behaviour change. If diet alone hasn't worked, your GP can discuss prescription options like Mounjaro or Wegovy, which are designed to be used alongside dietary changes.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. In clinical trials, Mounjaro showed slightly higher average weight loss (up to 21% body weight) compared to Wegovy (around 15%), though individual results vary. Both are once-weekly injections and require a prescription.
How long does it take to see weight loss results with medication?
Most people notice changes within the first few weeks—reduced appetite and fullness are often the first effects. Significant weight loss typically becomes visible over 8–12 weeks, with continued results over several months. Results are gradual and sustainable rather than rapid, which supports better long-term outcomes.
Do I need to change my diet if I take weight loss medication?
Yes. GLP-1 and GLP-1/GIP medications are most effective when combined with a reduced-calorie diet and increased physical activity. Prepared meals can help by providing structured, portion-controlled options, but medication is not a substitute for lifestyle changes—it's a tool to support them.
How do I know if I'm eligible for prescription weight loss medication?
You're typically eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or heart disease. Use the BMI calculator on this page, then speak to your GP about eligibility. Private prescribing services assess eligibility via online consultation as well.
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.