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
Gym Programme for Weight Loss — UK Health Guide
A structured gym programme is an effective foundation for sustainable weight loss. However, for many UK adults, combining exercise with medical support can improve results. Prescription weight management medications—available through NHS specialist services or private assessment—can help support your fitness goals when used alongside lifestyle changes like regular gym workouts and reduced-calorie eating. This guide covers both approaches so you can make informed decisions about what's 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.
Prescription Weight Management Options Available in the UK
If you're struggling to lose weight through gym exercise alone, prescription weight management medications may help. Three UK-licensed options are available for eligible adults:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist that may help reduce appetite and support feeling fuller. Clinical trials showed average weight loss of 15–21% of body weight when combined with lifestyle changes.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Evidence suggests average weight loss of around 15% of body weight at the maximum dose.
- Saxenda (liraglutide) — a daily GLP-1 injection option.
All three medications are prescription-only and require a clinical assessment. Eligibility typically requires a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Using our free GLP-1 weight loss calculator can help you explore projected results at different doses, though individual outcomes vary significantly.
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
NHS Route: Your GP can refer you to a tier 3 specialist weight management service in your area. NHS weight loss medication is typically prescribed through these specialist teams, though availability and waiting times vary significantly by region.
Private Route: You can access these medications through a private consultation with a UK-licensed prescriber, without NHS referral. This path is often faster but involves out-of-pocket costs.
Either way, a prescriber will assess your individual health to confirm eligibility. Speak to your GP about which option suits you best. Use our free BMI calculator above to check where you stand, and discuss prescription weight management as part of your overall fitness and wellness plan.
- 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.
Should I use a gym programme or weight loss medication?
Both work best together. Exercise builds fitness, strength, and mental health. Prescription weight management medication—when eligible—can reduce appetite and support adherence to a reduced-calorie diet. Most people benefit from combining lifestyle changes (including gym work) with medical support rather than relying on one approach alone.
How long does it take to see weight loss results?
With a gym programme alone, most people see modest results within 4–6 weeks. With prescription medication combined with exercise, clinical trials show measurable weight loss within 4 weeks, with progressive loss over 12–16 weeks. Results vary individually. Track your progress using our free progress tracker.
What BMI do I need to qualify for prescription weight loss medication?
Generally, a BMI of 30 or above, or 25–29.9 with weight-related health conditions. If you're of South Asian, Chinese, Black African, or Black Caribbean descent, lower thresholds may apply. Use our BMI calculator to check your personal BMI, then discuss prescription options with your GP.
Can I use weight loss medication without changing my gym routine?
Prescription medications work best alongside lifestyle changes—including regular physical activity and reduced-calorie eating. They support these changes rather than replace them. Your GP or prescriber will explain how to combine medication with your gym programme for best results.
How do I know if I'm eligible for NHS weight loss medication?
Contact your GP first. They can assess your BMI, health conditions, and eligibility for NHS tier 3 specialist weight management services. Alternatively, you can complete a private clinical assessment through a UK-registered online prescriber, which typically takes 24–48 hours.
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.