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
Vegetable Weight Loss and Prescription Medication in the UK
Eating more vegetables is an excellent foundation for weight management, but for some people, prescription medication can provide additional support. If you're interested in weight management in the UK, you may be eligible for licensed medications like Mounjaro or Wegovy alongside dietary changes. This guide explains how prescription weight loss options work, who qualifies, and how to find out if medication might be right for you. Use our free BMI calculator above to check your starting point.
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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 Weight Loss Medications Available Now
Three prescription-only weight management medications are currently licensed in the UK for adults with excess weight. These are available through the NHS and private prescribing:
- Mounjaro (tirzepatide) — once-weekly injection, dual GIP and GLP-1 agonist. Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks.
- Wegovy (semaglutide) — once-weekly injection, GLP-1 agonist. STEP trial data showed approximately 15% average weight loss at the highest dose.
- Saxenda (liraglutide) — once-daily injection, GLP-1 agonist. Effective for weight management but requires daily injections.
All three are prescribed as part of a structured weight management programme that includes dietary changes and increased physical activity — medication alone does not produce lasting results. Individual results vary significantly. Your GP or a licensed prescriber will assess whether medication is appropriate for your individual situation.
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 Eligibility
NHS access: Prescription weight loss medication is available through specialist tier 3 weight management services, typically accessed via GP referral. However, availability varies widely by region, and waiting lists can be lengthy in many areas.
Private access: Available through registered online prescribers following a clinical assessment, without needing an NHS referral. This option provides faster access but involves private costs (typically £129–£320 monthly depending on dose).
Eligibility: Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, hypertension, cardiovascular disease, sleep apnoea), may qualify. Lower BMI thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. Check your BMI using the calculator on this page, then speak with your GP about whether medication might be appropriate for 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.
Do I need to be on a diet to use prescription weight loss medication?
Yes. Weight loss medications like Mounjaro and Wegovy are only prescribed alongside a reduced-calorie diet and increased physical activity. They support and enhance lifestyle changes rather than replace them. Your prescriber will discuss dietary expectations before starting treatment.
How quickly will I see weight loss results with medication?
Weight loss typically begins within the first few weeks, with most noticeable changes appearing over 2–3 months. However, individual results vary significantly. Some people lose more weight than others at the same dose. Your prescriber will monitor progress regularly.
Can I take weight loss medication if I'm already eating healthily and exercising?
Yes. If you meet the BMI eligibility criteria and your GP or prescriber assesses you as suitable, medication can be prescribed regardless of your current activity level. It may help you achieve additional weight loss beyond what diet and exercise alone provide.
What happens if I stop taking the medication?
Weight loss effects gradually reverse once you stop taking the medication. Most people regain some weight over time without ongoing medication and lifestyle support. This is why long-term management and sustained dietary habits are important for lasting results.
Is weight loss medication available on the NHS in my area?
Availability varies significantly by region and NHS integrated care board. Contact your GP to ask about referral to your local specialist weight management service. Private online prescribing offers faster access but involves costs. Either route requires a clinical assessment first.
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.