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
Foods That Help With Weight Loss — And What Else You Need to Know
While choosing nutrient-dense foods is an important part of weight management in the UK, sustainable weight loss requires a combination of dietary changes, physical activity, and sometimes medical support. For eligible adults, prescription weight loss medications like Mounjaro and Wegovy are now available through the NHS and private prescribing. This guide explores both dietary approaches and the UK-licensed medication options that can support your weight management journey alongside healthy eating habits.
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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 Prescription Weight Loss Options
For adults struggling with weight management in the UK, prescription medications offer an evidence-based option alongside dietary changes. Mounjaro (tirzepatide) is a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist, helping to reduce appetite and support feeling fuller after meals. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks—though individual results vary significantly. Wegovy (semaglutide) is another once-weekly GLP-1 injection approved for weight management, with average weight loss of around 15% in clinical trials. Saxenda (liraglutide) is a daily GLP-1 injection also licensed in the UK. You may be eligible if you have a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. These are prescription-only medicines requiring a clinical assessment before being prescribed.
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 and Next Steps
In the UK, prescription weight loss medication is available through two routes. NHS access is via specialist tier 3 weight management services—you'll need a GP referral, though availability and waiting times vary significantly by region. Private access is through GPhC-registered online pharmacies following an online clinical assessment, and is available without NHS referral. Whichever route you choose, medication works best alongside a reduced-calorie diet and increased physical activity. Start by calculating your BMI using our free BMI calculator above to understand your current health status. If you think you may be eligible, speak with your GP about weight loss options suitable for your situation.
Practical Steps for Weight Loss SupportSustainable weight loss typically involves losing 0.5–1 kg per week, achieved through a calorie deficit of around 500 kcal daily alongside whole foods, lean proteins, and vegetables. Even a 5% reduction in body weight can improve blood pressure, blood sugar control, and joint health. Our free GLP-1 weight loss calculator can help you explore potential results with prescription medication at different doses, whilst our progress tracker lets you log your weight loss journey week by week. Whether you choose dietary changes alone or combine them with prescription medication, consistency matters more than perfection.
- 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 foods should I eat for weight loss?
Focus on nutrient-dense, protein-rich foods like lean meat, fish, eggs, and Greek yoghurt; plenty of vegetables and whole grains; and healthy fats from nuts and olive oil. These keep you fuller for longer and support sustainable weight loss. Avoid highly processed foods, sugary drinks, and excessive calorie-dense snacks.
Can prescription weight loss medication help me?
Yes, if you're eligible. Mounjaro and Wegovy are UK-licensed medications that, combined with dietary changes and exercise, helped participants lose significant weight in clinical trials. Eligibility depends on your BMI and health conditions. Your GP can assess whether medication is suitable for you.
How do I access weight loss medication on the NHS?
Ask your GP for a referral to your local tier 3 specialist weight management service. They'll assess your eligibility and discuss options. Availability varies by region and waiting times can be long in some areas.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly injections, but Mounjaro uses a dual GIP+GLP-1 mechanism whilst Wegovy uses GLP-1 only. Clinical trial data suggests Mounjaro may produce slightly greater average weight loss, though individual results vary significantly.
How quickly will I lose weight with these medications?
Weight loss typically occurs gradually over weeks and months. Clinical trials showed average losses of 15–21% over 72 weeks with Mounjaro and around 15% with Wegovy. However, individual results vary based on dose, diet, activity, and other factors.
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.