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
2 Meals A Day Weight Loss — UK Prescription Medication Guide
Eating just 2 meals a day is one approach some people try for weight management in the UK, though healthcare professionals typically recommend eating regular, balanced meals alongside physical activity. If you're exploring weight loss options, prescription medications are available for eligible adults in the UK. These work differently than meal restriction alone, actively supporting appetite regulation and weight management. Our GLP-1 weight loss calculator can help you understand potential outcomes with medication support. This guide covers UK-licensed prescription options, eligibility criteria, and how to access them through the NHS or private prescribers.
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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 Medications
Three prescription medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide), a GLP-1 agonist; and Saxenda (liraglutide), also a GLP-1 agonist. In clinical trials, these medications helped participants lose an average of 14–21% of their body weight when combined with reduced-calorie diet and increased physical activity—though individual results vary significantly.
Eligibility in the UK 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 cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher health risks at lower weights. All three medications are prescription-only and require a clinical assessment to determine suitability before prescription.
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.
Accessing Prescription Weight Loss Treatment in the UK
NHS access requires referral to a tier 3 specialist weight management service through your GP. Availability varies significantly by region, and waiting times can be lengthy in many areas. Private access is available through GPhC-registered online prescribing services following an online clinical assessment—no NHS referral required.
Prescription medication works most effectively alongside lifestyle changes, not instead of them. Your GP or a licensed prescriber will assess your individual health, current medications, and weight loss goals to determine whether medication is appropriate for you. Use our BMI calculator above to check your current BMI category, and speak with your GP about prescription weight loss options if you're eligible and interested.
- 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.
Is eating 2 meals a day safe for weight loss?
Eating 2 meals daily may result in weight loss through calorie restriction, but the NHS recommends a balanced approach with regular meals and physical activity. Individual needs vary—some people feel satisfied on 2 meals, whilst others need more frequent eating. Consult your GP about any significant dietary changes, especially if you have health conditions or take medications.
What prescription weight loss medications are available in the UK?
Three medications are licensed for weight management in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All are GLP-1 or GIP/GLP-1 receptor agonists that support appetite regulation. Clinical trials show average weight loss of 14–21% when used with diet and exercise. Individual results vary, and all require prescription and clinical assessment.
Who is eligible for prescription weight loss medication in the UK?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes, high blood pressure, or cardiovascular disease. Lower BMI thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. A prescriber will assess your individual circumstances, health history, and suitability before prescription.
How do I access prescription weight loss medication—NHS or private?
NHS access requires a GP referral to a specialist tier 3 weight management service; availability varies by region and waiting times can be long. Private access is available through GPhC-registered online prescribers following a clinical assessment—no NHS referral needed. Both routes require a prescription from a UK-licensed prescriber.
Do prescription weight loss medications work without diet and exercise changes?
No. Prescription medications like Mounjaro and Wegovy are most effective when combined with a reduced-calorie diet and increased physical activity. Medication supports appetite regulation and fullness, but sustained weight loss requires lifestyle changes. Your prescriber will discuss realistic expectations and how medication fits into your overall weight management plan.
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.