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 in the UK
If you're looking for weight loss support without paying upfront, the UK offers several free options through the NHS, alongside prescription medications for eligible adults. The NHS provides free weight management services across three tiers, from self-help digital tools to specialist services. For those who qualify based on BMI and health conditions, prescription weight loss medications like Mounjaro and Wegovy are also available. This guide explains your free and low-cost options, how to access them, and whether prescription weight management might be right for you.
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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 a BMI of 27–29.9 with weight-related health conditions, you may be eligible for prescription weight loss medication through the NHS or privately. The UK's three main licensed options are:
- Mounjaro (tirzepatide) — dual GIP and GLP-1 injection, once weekly. Clinical trials showed participants lost an average of 15–21% of their body weight alongside diet and exercise changes.
- Wegovy (semaglutide) — GLP-1 injection, once weekly. Evidence from clinical trials indicates average weight loss of around 15% of body weight.
- Saxenda (liraglutide) — GLP-1 injection, once daily. Typically associated with 5–clinically studied weight loss over sustained use.
All three are prescription-only and require a clinical assessment. Your GP can refer you to NHS specialist weight management services, or you can access private prescribing through a UK-licensed online prescriber. Check your BMI using our free BMI calculator to see if you may be 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 vs Private Access — How to Get Started
The NHS offers free weight management support through three tiers: Tier 1 includes digital tools and community weight loss programmes; Tier 2 involves GP-led behaviour change support; Tier 3 is specialist multidisciplinary services where prescription medications are prescribed. NHS access is free but waiting lists vary significantly by region — some areas have waits of several months or more. Private prescription weight loss is available immediately through online consultations with UK-licensed prescribers, though you'll pay for the medication (typically £129–£320 monthly depending on dose). Start by speaking to your GP about your weight loss goals and asking about local NHS weight management referral options. Our free GLP-1 weight loss calculator can help you explore projected outcomes if you become eligible for medication.
- 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.
Are there completely free weight loss programs in the UK?
Yes. The NHS offers free Tier 1 weight management programmes including digital tools, community weight loss groups, and online behaviour change support. Your GP can refer you to these at no cost. Tier 2 (GP-led) and Tier 3 (specialist services) are also free on the NHS, though prescription medications carry a cost if you don't qualify for NHS prescribing.
Who qualifies for prescription weight loss medication on the NHS?
Adults with a BMI of 30 or above, or BMI of 27–29.9 with at least one weight-related health condition (type 2 diabetes, high blood pressure, heart disease, sleep apnoea, or abnormal cholesterol), may qualify. Lower BMI thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. Your GP or specialist will assess your individual eligibility.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) works on two pathways (GIP and GLP-1) while Wegovy (semaglutide) targets GLP-1 only. Clinical trials suggest Mounjaro may produce slightly greater average weight loss (15–21% vs around 15%), though individual results vary significantly. Both are once-weekly injections. A prescriber will advise which is most suitable for you.
How long does it take to access weight loss medication through the NHS?
NHS timelines vary greatly by region. Some areas have waiting lists of 3–6 months for initial specialist assessment, while others may have longer waits. Private prescription options are typically available within days of online consultation, though you'll pay for the medication. Discuss NHS availability with your GP.
Do I need to diet and exercise if I take weight loss medication?
Yes. Prescription weight loss medications like Mounjaro and Wegovy work best alongside a reduced-calorie diet and regular physical activity. Clinical trial evidence shows weight loss occurs when medication is combined with lifestyle changes. Medication alone without behaviour change typically produces less sustained results. Your GP or weight management specialist will support you with practical guidance.
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.