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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Best Fitness Plan for Weight Loss in the UK
Finding the best fitness plan for weight loss depends on your starting point, lifestyle, and health. While exercise and diet are fundamental, UK adults with a BMI of 30 or above—or 27 or above with weight-related health conditions—may also be eligible for prescription weight loss medication. This guide covers exercise strategies, how to calculate your personal BMI, and what NHS weight management options are available to you. The most effective approach combines fitness, dietary changes, and professional support tailored to your individual needs.
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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 Weight Management Options: Exercise, Lifestyle, and Prescription Support
The best fitness plan for weight loss in the UK starts with understanding your current health status. Use our free BMI calculator above to establish your baseline, then work with your GP or a weight management service to build a plan suited to you.
Exercise component: The NHS recommends at least 150 minutes of moderate aerobic activity per week (brisk walking, cycling, swimming) plus muscle-strengthening activities twice weekly. This helps preserve muscle during weight loss and improves cardiovascular health.
Prescription weight management options available in the UK include:
- Mounjaro (tirzepatide) — a once-weekly GLP-1 and GIP receptor agonist injection. 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 approximately 15% average body weight loss alongside diet and exercise.
- Saxenda (liraglutide) — a daily GLP-1 injection, available through NHS or private routes.
Eligibility for these medications depends on BMI and health status. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses if you're considering medication-supported weight loss.
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: Finding Your Weight Management Pathway
In the UK, you can access weight loss medication through two routes. NHS access is through tier 3 specialist weight management services—you'll need a GP referral, and availability varies significantly by region. Waiting times can be lengthy in many areas. Private access is available through GPhC-registered online prescribing services following a clinical assessment; this bypasses NHS waiting lists but involves personal cost.
Whichever route you choose, prescription weight loss medication works best alongside exercise and dietary changes—not as a replacement. Start by speaking with your GP about your weight management goals. They can assess your BMI using our free weight converter (if you're more familiar with stone and pounds), discuss eligibility, and advise whether NHS specialist referral or private assessment would suit you best. Even modest weight loss of 5–10% can bring meaningful health improvements.
- 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 is the best fitness plan for weight loss?
The best plan combines 150+ minutes of moderate aerobic activity weekly, strength training twice weekly, a moderate calorie deficit (around 500 kcal/day), and consistent lifestyle changes. The NHS recommends losing 0.5–1 kg per week. Prescription weight loss medications like Mounjaro or Wegovy may support this if you're eligible, but exercise and diet remain essential.
Can I get weight loss injections through the NHS in the UK?
Yes. Mounjaro, Wegovy, and Saxenda are NHS-available for eligible adults, but access is through specialist tier 3 weight management services. You'll need a GP referral and may face waiting lists. Your GP can assess whether you meet eligibility criteria (BMI 30+ or 27+ with weight-related health conditions).
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections for weight loss. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with average clinical trial weight loss of 15–21%. Wegovy (semaglutide) is a GLP-1 agonist with approximately 15% average weight loss. Both require prescription and clinical assessment. Your GP or prescriber can discuss which suits your health profile.
How quickly will I lose weight with exercise alone?
With exercise and a moderate calorie deficit, most people lose 0.5–1 kg per week. Faster loss is possible with medical support, but this rate is sustainable and reduces muscle loss. Use our BMI calculator to track progress and adjust your plan if needed. Individual results vary based on starting weight, age, metabolism, and consistency.
What should I do if I'm overweight and unsure where to start?
Start by calculating your BMI using our free BMI calculator on this page. If your BMI is in the overweight or obese range, book an appointment with your GP to discuss your options. They can refer you to NHS weight management services or discuss prescription options if eligible. Combining exercise, dietary changes, and professional guidance gives you the best chance of success.
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.