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
Weight Loss Program For Free — UK Options and Support
If you're looking for a weight loss program in the UK, you have several options available at no cost or through affordable prescription routes. The NHS offers free weight management support through tier 1 and tier 2 services, whilst prescription medications like Mounjaro and Wegovy are available for eligible adults. Our free BMI calculator and weight loss projection tools can help you understand your starting point and explore what options might suit you best.
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 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 management support. The UK currently has three licensed medications available:
- Mounjaro (tirzepatide) — a once-weekly GLP-1 and GIP receptor agonist injection. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks alongside dietary changes and increased physical activity. Individual results vary.
- Wegovy (semaglutide) — a once-weekly GLP-1 receptor agonist. Evidence suggests average weight loss of approximately 15% body weight at the maximum dose, with results varying significantly between individuals.
- Saxenda (liraglutide) — a daily GLP-1 injection, less commonly prescribed than the once-weekly options.
All are prescription-only medicines requiring a clinical assessment before prescribing. Weight loss medication works most effectively alongside reduced-calorie diet and increased physical activity — it is not a substitute for lifestyle changes.
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 — Finding Your Pathway
The NHS provides free weight loss support through its tiered weight management pathway. Tier 1 includes self-help resources, digital tools, and community programmes (often free or very low cost). Tier 2 offers behaviour change support from your GP practice. Tier 3 is specialist weight management services where prescription medication may be initiated — however, NHS access to medications like Mounjaro varies significantly by region and can involve lengthy waiting lists.
Alternatively, prescription weight loss medication is available through private online prescribing services following a clinical assessment by a UK-licensed prescriber. Use our free GLP-1 weight loss calculator to estimate potential weight loss at different doses, and discuss any option with your GP before starting treatment. Weight management success depends on sustained lifestyle change — our free progress tracker can help you log your weight loss journey over time.
- 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.
Is there a completely free weight loss program available on the NHS?
Yes. The NHS offers free tier 1 and tier 2 weight management support including digital tools, self-help resources, and GP-led behaviour change programmes. These are available to all adults in England. Access through your GP to enquire about what's available in your local area (ICB). Waiting times vary by region.
How do I know if I'm eligible for prescription weight loss medication in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related conditions such as type 2 diabetes, high blood pressure, or heart disease. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply. A GP or licensed prescriber can assess your eligibility based on your individual health.
What's the difference between NHS and private weight loss medication access?
NHS access is through specialist tier 3 services (usually free but with variable waiting lists and regional availability). Private access is through online prescribing services following a clinical assessment (not NHS-funded, costs typically £130–£320/month depending on dose). Both require a valid prescription from a UK-licensed prescriber.
Can I use a weight loss medication without making dietary changes?
No. Prescription weight loss medications work most effectively alongside a reduced-calorie diet and increased physical activity. They are not a standalone solution. Clinical trials showing weight loss results all involved participants making lifestyle changes. Your prescriber will discuss this expectation with you.
How can I start a weight loss programme if I'm not sure about medication?
Begin with free tier 1 support — speak to your GP about NHS weight management resources, digital apps, and community programmes available in your area. Use our free BMI calculator and weight converter to understand your health metrics. Track your progress with our free progress tracker. If lifestyle changes alone aren't sufficient, discuss prescription options with your GP as a next step.
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.