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
Exercise for Weight Loss — How It Works with UK Medication
Exercise is a cornerstone of sustainable weight management in the UK, but for many people, physical activity alone isn't enough. When combined with prescription weight loss medication and a reduced-calorie diet, exercise can significantly improve results. The NHS recommends combining regular physical activity with lifestyle changes and, where eligible, prescription weight management options. Our GLP-1 weight loss calculator can help you explore how medication might complement your exercise routine if you meet eligibility criteria.
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 Management Medications
Three prescription-only weight loss medications are licensed in the UK for adults with obesity or overweight with health complications: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These GLP-1 and dual GIP/GLP-1 medications work alongside exercise by reducing appetite and supporting healthier eating patterns—they are not replacements for physical activity. Clinical trials showed that when combined with a reduced-calorie diet and increased exercise, these medications help participants lose an average of 15–21% of body weight, though individual results vary significantly.
- Mounjaro: Dual GIP/GLP-1 receptor agonist, once-weekly injection, doses 2.5–15 mg
- Wegovy: GLP-1 receptor agonist, once-weekly injection, maximum dose 2.4 mg
- Saxenda: GLP-1 receptor agonist, daily injection, maximum dose 3 mg
Eligibility includes adults with a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. South Asian, Chinese, Black African, and Black Caribbean adults may be eligible at lower BMI thresholds due to increased health risks at lower weights.
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 Weight Loss and How to Access Prescription Support
The NHS offers weight management support through a tiered pathway: Tier 1 includes self-help digital tools and community programmes; Tier 2 involves primary care-based behaviour change support; Tier 3 includes specialist multidisciplinary weight management services where prescription weight loss medication may be initiated. Accessing prescription medication typically requires referral to a Tier 3 service through your GP, though availability varies significantly by region and waiting lists can be lengthy.
Alternatively, prescription weight loss medications are available privately through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. Our free BMI calculator can help you check if you fall within the typical eligibility criteria, though a prescriber will make the final decision based on your individual health. Speak with your GP about the best weight management approach for you, combining exercise, dietary changes, and where appropriate, prescription support.
- 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.
Can exercise alone help me lose weight without medication?
Yes, exercise combined with a calorie deficit can support weight loss. The NHS recommends regular physical activity alongside a reduced-calorie diet. However, for some people—particularly those with obesity or weight-related health conditions—adding prescription medication can significantly improve results. A GP can advise whether medication might benefit you.
What type of exercise is best for weight loss in the UK?
The NHS recommends at least 150 minutes of moderate-intensity aerobic activity (brisk walking, cycling, swimming) per week, plus strength training twice weekly. Consistency matters more than intensity. If you're starting exercise after being inactive, begin gradually and consider consulting your GP, especially if you have existing health conditions.
How do weight loss injections like Mounjaro work with exercise?
Prescription weight loss medications reduce appetite and support feeling fuller after smaller meals, which can make it easier to maintain a calorie deficit while exercising. They are not replacements for physical activity—clinical trials showed best results when medication was combined with both exercise and dietary changes.
Am I eligible for prescription weight loss medication on the NHS?
NHS eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions like type 2 diabetes or high blood pressure. Referral to a specialist Tier 3 weight management service through your GP is usually necessary. Availability varies by region. Use our free BMI calculator to check your BMI, then discuss options with your GP.
What's the difference between NHS and private weight loss medication access in the UK?
NHS access requires GP referral to specialist services (Tier 3) and may involve waiting lists. Private access is available through online prescribers and GPhC-registered pharmacies without NHS referral, though you'll pay privately. Both require a clinical assessment to ensure the medication is appropriate for your health.
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.