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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Healthy Bread and Weight Loss — Prescription Options in the UK
When focusing on healthy bread choices for weight loss, many UK adults wonder about prescription medication support. Prescription weight management medication isn't a replacement for healthy eating—it works alongside dietary changes, including choosing nutritious bread options. The NHS and private healthcare in the UK now offer several licensed prescription options for eligible adults. Understanding how these medications fit into a weight management UK approach, combined with sensible food choices, can help you make informed decisions about your health journey.
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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 Management Options
Three prescription-only medications are licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All work by activating GLP-1 receptors (and GIP in Mounjaro's case), which help regulate appetite and support feeling fuller after meals. Clinical trials showed that GLP-1 weight loss injections help participants lose an average of 15–21% of their body weight when combined with dietary changes and increased physical activity—though individual results vary significantly.
- Mounjaro: Once-weekly injection, doses 2.5–15mg, dual GIP+GLP-1 mechanism
- Wegovy: Once-weekly injection, doses 0.25–2.4mg, GLP-1 only
- Saxenda: Once-daily injection, doses 0.6–3mg, GLP-1 only
Eligibility typically requires a BMI of 30kg/m² or above, or 27–29.9kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Lower thresholds apply for adults of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP or a licensed prescriber will assess whether prescription weight loss medication is suitable for you based on your individual health.
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 in the UK
NHS access: Prescription weight loss medication is available through specialist tier 3/4 weight management services, typically requiring a GP referral. However, NHS availability varies significantly by region, and waiting lists can be lengthy in many areas. You can ask your GP about referral to your local NHS weight management service to explore whether you're eligible.
Private access: GLP-1 medications are also available through UK-licensed online prescribers following a clinical assessment. This route does not require NHS referral and offers faster access, though costs vary by dose and provider. Whichever route you choose, combining prescription support with healthy food choices—including sensible bread selection—and increased physical activity gives you the best chance of sustainable weight loss. Use our free BMI calculator to check your current status, and speak with your GP about which weight loss option might suit you.
- 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 prescription weight loss medication if I'm overweight but not obese?
Yes, if you have a BMI of 27–29.9kg/m² and at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea), you may be eligible for prescription medication. Adults of South Asian or Black heritage may have lower BMI thresholds. Always discuss eligibility with your GP or a licensed prescriber.
Do weight loss injections replace healthy eating and exercise?
No. Prescription weight loss medication is designed to support, not replace, healthy dietary choices and physical activity. These medications work best when combined with a reduced-calorie diet, balanced nutrition (including sensible bread choices), and regular exercise. They help reduce appetite and cravings, making it easier to stick to healthier habits.
How long does it take to see weight loss results with prescription medication?
Most people begin to see noticeable weight loss within 4–8 weeks, though this varies individually. Medications are typically escalated gradually over weeks or months to find the right dose. Sustainable weight loss—around 0.5–1kg per week—is recommended. Clinical trial data showed average weight loss of 15–21% over several months alongside lifestyle changes.
Are there side effects with GLP-1 weight loss injections?
Common side effects include nausea, diarrhoea, constipation, and stomach discomfort, especially when starting or increasing doses. These often improve over time. Serious side effects are rare but can include pancreatitis or gallbladder problems. Always report any concerning symptoms to your prescriber immediately.
How do I find out if I'm eligible for prescription weight loss medication?
The first step is speaking with your GP, who can assess your BMI, health conditions, and medical history. If eligible, your GP can refer you to an NHS specialist weight management service or discuss private options. Alternatively, you can use our free BMI calculator on this page to check your starting point, then arrange a consultation with your GP or a licensed online prescriber.
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.