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
Does Exercise Help In Weight Loss?
Yes, exercise is an important part of weight loss, but it works best alongside dietary changes and, for some people, prescription medication. Physical activity helps burn calories, builds muscle, improves cardiovascular health, and supports sustainable weight management. However, for adults with obesity or weight-related health conditions, UK-licensed prescription options like Mounjaro and Wegovy may provide additional support when combined with lifestyle changes. This guide explains how exercise contributes to weight loss and what other options are available through NHS weight management or private prescribing in the UK.
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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.
Exercise and Weight Loss: The Evidence
Exercise does help weight loss, but the evidence shows that diet is the primary driver of weight loss results. A calorie deficit — consuming fewer calories than you burn — is essential. Exercise contributes by:
- Burning additional calories during activity
- Building and maintaining muscle mass (which increases resting metabolic rate)
- Improving cardiovascular fitness and overall health
- Supporting mental wellbeing and motivation
The NHS recommends at least 150 minutes of moderate-intensity activity per week alongside a reduced-calorie diet for sustainable weight loss. However, exercise alone, without dietary changes, typically results in modest weight loss. For weight management in the UK, adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, may also be eligible for prescription support. Our GLP-1 weight loss calculator can help you estimate how different weight loss approaches might work for your situation.
Clinically BackedWeight Loss
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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.
Prescription Weight Loss Options in the UK
For eligible adults, prescription weight loss medication is available on the NHS through specialist tier 3 weight management services, or privately through GPhC-registered online prescribers. UK-licensed options include Mounjaro (tirzepatide) and Wegovy (semaglutide), both once-weekly injections that work alongside exercise and diet to support nhs weight loss goals. Clinical trials show these medications can help participants lose an average of 15–21% of body weight (results vary individually). Eligibility is assessed on an individual basis by a prescriber. To find out if prescription weight loss medication might be suitable for you, speak to your GP, who can refer you to specialist services or discuss private prescribing options. Our free BMI calculator can help you check your starting point.
- 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 exercise enough for weight loss without changing diet?
Exercise alone typically produces modest weight loss. Research shows diet is the primary driver — a calorie deficit from reduced food intake produces more significant results. Combining exercise with dietary changes is most effective. For some people, prescription weight loss medication alongside lifestyle changes provides additional support.
How much exercise do I need for weight loss?
The NHS recommends at least 150 minutes of moderate-intensity activity (like brisk walking) per week, alongside a reduced-calorie diet. Consistency matters more than intensity. Regular activity improves fitness, supports mental health, and helps maintain muscle during weight loss.
Can I lose weight with exercise and Mounjaro or Wegovy together?
Yes. Prescription weight loss medications like Mounjaro and Wegovy are designed to be used alongside lifestyle changes — reduced-calorie diet and increased physical activity. The medication supports appetite regulation while exercise and diet create the calorie deficit needed for weight loss.
How do I know if I'm eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, high blood pressure, heart disease), may be eligible. Your GP can assess eligibility and refer you to specialist NHS services or discuss private prescribing options. Speak to your GP to start a conversation.
Does lose weight uk have different guidance than NHS recommendations?
The NHS provides the main evidence-based guidance for weight management in the UK. A sustainable approach involves a modest calorie deficit (500 kcal per day for approximately 0.5kg per week loss), increased physical activity, and where appropriate, prescription support. Individual circumstances vary — your GP can give personalised advice.
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.