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
Vegan Weight Loss Diet: Nutrition & UK Medication Options
A vegan weight loss diet can be highly effective when balanced properly, combining plant-based nutrition with calorie awareness. In the UK, many people lose weight successfully through vegan eating, though some may benefit from additional support. If you're struggling to reach your weight loss goals through diet alone, prescription weight management options are available for eligible adults. Our free BMI calculator can help you assess where you stand, and our GLP-1 weight loss calculator can show potential results if medication might be right for you.
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 Weight Loss Medication Options
If a vegan diet and lifestyle changes aren't delivering the results you need, several prescription weight management medications are available in the UK for eligible adults. These are designed to work alongside diet and exercise, not replace them.
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist, given as a once-weekly injection. Clinical trials showed average weight loss of 15–21% body weight over 72 weeks.
- Wegovy (semaglutide) — a GLP-1 receptor agonist, once-weekly injection. Average weight loss in trials was approximately 15% body weight.
- Saxenda (liraglutide) — a daily GLP-1 injection option, with average weight loss around 5–10% body weight.
All are prescription-only and require a clinical assessment. Eligibility depends on your BMI and whether you have weight-related health conditions.
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 & Next Steps
In the UK, weight loss medication can be accessed through NHS specialist services (tier 3 weight management services) or private prescribing. NHS access typically requires a GP referral and varies significantly by region — waiting times can be lengthy in many areas. Private access is faster and available without NHS referral, via an online assessment with a UK-licensed prescriber.
Start by speaking with your GP about your weight loss goals and whether you might be eligible. They can assess your BMI, health conditions, and discuss whether prescription medication could support your vegan weight loss journey. Use our free progress tracker to log your current weight and monitor changes as you make dietary or medication 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.
Can you lose weight on a vegan diet without medication?
Yes, many people lose weight successfully on a vegan diet through calorie deficit and balanced nutrition. However, some people find additional support helpful. The NHS recommends losing 0.5–1 kg per week. If diet alone isn't working after several months, speak to your GP about other options.
What is the eligibility criteria for weight loss medication in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions like high blood pressure, type 2 diabetes, or sleep apnoea. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply. A GP or prescriber will assess your individual eligibility.
How does GLP-1 medication work with a vegan diet?
GLP-1 medications help reduce appetite and support feeling fuller after smaller meals. They work alongside your vegan diet and lifestyle changes — not instead of them. Most people continue their normal eating pattern but find they eat less naturally whilst on medication.
How quickly can I expect weight loss results with medication?
Results vary individually, but clinical trials showed average weight loss over several weeks to months. Results improve at higher doses, which are typically reached gradually (minimum 4 weeks at each dose). Remember, medication works best combined with a healthy vegan diet and physical activity.
What should I do if my GP says I'm not eligible for NHS medication?
Ask about private prescribing options, which are available without NHS referral. You can also request a referral to a specialist weight management service for a second opinion. Private assessments are conducted by UK-licensed prescribers and are often quicker than NHS routes.
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.