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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Free Weight Loss Programs Available in the UK
If you're looking for free weight loss programs in the UK, the NHS offers several options ranging from self-help digital tools to specialist medication services. For eligible adults, prescription weight management medication like Mounjaro and Wegovy is available through NHS specialist weight management services or private prescribing. This guide explains what's available, how to access them, and whether prescription weight loss medication might be right for you. Individual results vary, so understanding your options is the first step.
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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 Options
If you have a BMI of 30 or above (or 27 or above with weight-related health conditions), you may be eligible for prescription weight loss medication in the UK. Three options are currently licensed for weight management:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 injection, once weekly. In clinical trials, participants lost an average of 15–21% of body weight over 72 weeks alongside a reduced-calorie diet and physical activity.
- Wegovy (semaglutide) — a GLP-1 injection, once weekly. Clinical trials showed average weight loss of around 15% of body weight at the maximum dose.
- Saxenda (liraglutide) — a GLP-1 injection, once daily. A longer-established option with proven efficacy in weight loss.
All three are prescription-only medicines requiring a clinical assessment. Individual weight loss results vary significantly based on lifestyle changes, adherence, and personal factors. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses.
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 — What You Need to Know
NHS access to prescription weight loss medication is through specialist tier 3 weight management services. You'll need a GP referral, and availability varies by region—waiting lists can be several months or longer depending on your area.
Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. This route doesn't require NHS referral and is typically faster, though costs range from approximately £129–£320 per month depending on dose.
Both routes require a clinical assessment to confirm eligibility and suitability. Your GP can discuss which option is appropriate for you. Check your BMI using our free BMI calculator above, then speak to your healthcare provider about whether prescription weight loss treatment is right 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.
What's the difference between free NHS weight loss programs and prescription medication?
Free NHS programs include digital tools, community programmes, and behavioural support through your GP (tier 1 and 2). Prescription weight loss medication is available through NHS specialist services (tier 3) and private providers. The NHS also funds tier 1 services for everyone; medication access depends on eligibility and referral to specialist services.
How do I know if I'm eligible for prescription weight loss medication?
You're typically eligible if you have a BMI of 30 or above, or 27 or above with at least one weight-related health condition (like type 2 diabetes, high blood pressure, or sleep apnoea). For people of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply. Your GP or a prescriber can assess your individual eligibility.
How much weight can I expect to lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% of body weight with Mounjaro and around 15% with Wegovy, but individual results vary significantly. Weight loss depends on your starting weight, how well you stick to dietary changes and physical activity, and how your body responds to the medication. Use our weight loss calculator to see projected ranges.
Can I access prescription weight loss medication on the NHS without a waiting list?
NHS access is through specialist weight management services, which often have waiting lists depending on your region. Private prescribing via online services is typically faster but involves a cost. Ask your GP about waiting times and whether private options are available to you if you prefer quicker access.
What lifestyle changes do I need to make alongside weight loss medication?
Prescription weight loss medications work best alongside a reduced-calorie diet and increased physical activity. The NHS recommends aiming for a weight loss of 0.5–1 kg per week. Track your progress using our free progress tracker, combine it with balanced nutrition, and aim for at least 150 minutes of moderate activity per week.
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.