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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Gym Exercise Plan For Weight Loss — UK Medication Options
A gym exercise plan is an effective foundation for weight loss, but combining fitness with prescription medication can amplify your results. In the UK, eligible adults can access prescription weight management options like Mounjaro and Wegovy alongside their gym routine. This guide explains how UK-licensed medications work alongside exercise, eligibility criteria, and how to explore these options with your GP. Use our free BMI calculator to understand your starting point and our GLP-1 weight loss calculator to see how medication might support your fitness goals.
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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 Prescription Weight Loss Options — What's Available
Three prescription medications are currently licensed in the UK for weight management:
- Mounjaro (tirzepatide) — a once-weekly injection that works via dual GIP and GLP-1 pathways. Clinical trials showed participants lost an average of 15–21% of body weight when combined with diet and exercise.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Trial data demonstrated average weight loss of around 15% body weight at the maximum dose, alongside lifestyle changes.
- Saxenda (liraglutide) — a daily GLP-1 injection. A longer-established option with robust evidence supporting modest weight loss.
All three are prescription-only and require clinical assessment before being prescribed. These medications may help reduce appetite and support feeling fuller, working synergistically with your gym exercise plan and dietary changes. Individual results vary significantly, and medication is never a substitute for physical activity and calorie reduction.
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.
Eligibility and NHS vs Private Access
You may be eligible for prescription weight loss medication if you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or sleep apnoea. Lower thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage.
NHS access: Referral through your GP to a specialist tier 3 weight management service. Availability varies by region and waiting lists can be lengthy. Private access: Online consultation with a UK-licensed prescriber followed by dispensing through a GPhC-registered pharmacy — available without NHS referral. Your GP can advise whether this medication is right for you. Use our BMI calculator above to check where you fall and start a conversation with your healthcare provider about combining gym exercise with tailored weight loss 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 I take weight loss medication while going to the gym?
Yes. Prescription weight loss medications are designed to work alongside diet and exercise, not replace them. In fact, gym exercise combined with medication typically produces better results than either approach alone. Always inform your prescriber about your fitness routine so they can monitor your progress safely.
How long does it take to see results from gym exercise and weight loss medication together?
Weight loss typically becomes noticeable within 2–4 weeks of starting medication, though individual timelines vary. Consistent gym exercise amplifies these results. The NHS recommends losing 0.5–1 kg per week for sustainable progress. Use our progress tracker to monitor your weight loss journey week by week.
Will I still need to go to the gym if I'm taking Mounjaro or Wegovy?
Yes. Whilst these medications reduce appetite, physical activity remains essential for long-term health, fitness, muscle preservation, and sustainable weight loss. A combination of reduced calorie intake, medication, and regular gym exercise provides the best outcomes. Exercise also supports cardiovascular health and mental wellbeing.
How do I find out if I'm eligible for prescription weight loss medication in the UK?
Start by calculating your BMI using our free BMI calculator on this page. If you fall into the eligible range, book an appointment with your GP to discuss prescription weight loss options. Your GP can refer you to NHS specialist services or advise on private prescribing routes based on your circumstances.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 medication showing slightly higher average weight loss (15–21%) compared to Wegovy (semaglutide), a GLP-1-only medication (around 15%). Both are once-weekly injections. A prescriber will determine which is more suitable for you based on your health profile and medical history.
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.