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
Cabbage Soup for Weight Loss — What UK Adults Need to Know
Cabbage soup diets have been popular for decades, but evidence shows they deliver only short-term results. If you're looking for sustainable weight management in the UK, prescription weight loss medication may be more effective. This guide explains why fad diets fall short and what NHS-approved options are available for eligible adults.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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
While cabbage soup diets create rapid initial weight loss through calorie restriction, they rarely lead to long-term results because they're not sustainable. The NHS recognises that for lasting weight management in the UK, a combination of lifestyle changes and, where appropriate, prescription support is more effective.
Three prescription weight loss medications are currently licensed in the UK for adults who qualify:
- Mounjaro (tirzepatide) — A dual GIP/GLP-1 receptor agonist injection. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks when combined with diet and exercise.
- Wegovy (semaglutide) — A GLP-1 receptor agonist injection. Evidence from clinical trials demonstrated approximately 15% average body weight loss alongside lifestyle changes.
- Saxenda (liraglutide) — A daily GLP-1 injection option. The SCALE trial showed average weight loss of around 8% of body weight.
These medications work by regulating appetite and supporting fullness — effects that no restrictive diet alone can sustain long-term. Use our free GLP-1 weight loss calculator to explore potential outcomes if you're eligible.
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 Access vs Private: How to Find Out If You Qualify
Eligibility for prescription weight loss medication in the UK depends on your BMI and health circumstances. Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, or cardiovascular disease), may qualify.
Check your personal BMI using our free BMI calculator above to see where you stand.
NHS route: Ask your GP for a referral to specialist weight management services — though waiting lists vary significantly by region. Private route: UK-licensed prescribers can conduct online assessments and issue prescriptions if appropriate, without NHS referral. Either way, a clinical assessment comes first — prescription weight loss isn't a structured approach, but a supported tool combined with dietary and physical activity changes.
- 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.
Does the cabbage soup diet actually work?
The cabbage soup diet can produce rapid short-term weight loss due to severe calorie restriction, but it's not sustainable. Most people regain the weight once they return to normal eating. The NHS recommends weight loss of 0.5–1 kg per week through balanced diet and activity changes, not restrictive fad diets.
What's the difference between fad diets and prescription weight loss medication?
Fad diets rely on extreme restriction and are hard to maintain. Prescription medications like Mounjaro and Wegovy work by regulating appetite hormones, making sustainable eating changes easier. Clinical trials show results of 15–21% average body weight loss compared to fad diets' temporary effects.
Who is eligible for weight loss medication on the NHS?
NHS eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. You'll need a GP referral to specialist weight management services, though availability varies by region. Private prescribers have similar criteria but don't require NHS referral.
How long do you stay on prescription weight loss medication?
Duration depends on individual circumstances and GP/prescriber guidance. Some people use medications for several months to kickstart weight loss and habit change, then stop. Others continue longer-term. The aim is to combine medication with sustainable dietary and activity changes.
Is prescription weight loss medication available privately in the UK?
Yes. UK-licensed prescribers can issue prescriptions for Mounjaro, Wegovy, and Saxenda following an online clinical assessment. These are dispensed by GPhC-registered pharmacies. Costs vary by dose and provider, typically ranging from £120–£320 monthly depending on the medication and stage of treatment.
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.