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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Weight Loss and Muscle Gain Workout Plan — UK Medication Guide
Building muscle while losing weight requires the right combination of exercise, nutrition, and in some cases, medical support. If you're carrying excess weight and want to improve your body composition, UK-licensed prescription weight loss medications like Mounjaro and Wegovy may support your efforts alongside a structured workout plan. This guide covers how prescription weight management works in the UK, who's eligible, and how medication fits into a realistic fitness and health strategy.
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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 Management Options
Three prescription-only weight management options are licensed in the UK:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist. Once-weekly injection, doses 2.5 mg to 15 mg. Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks when combined with reduced-calorie diet and exercise.
- Wegovy (semaglutide) — a GLP-1 receptor agonist. Once-weekly injection, doses 0.25 mg to 2.4 mg. Clinical trial data showed average weight loss of approximately 15% body weight at the maximum dose.
- Saxenda (liraglutide) — a GLP-1 receptor agonist. Daily injection, doses 0.6 mg to 3 mg. Effective for weight management though less commonly prescribed than weekly options.
All three work by helping reduce appetite, increase satiety, and support feeling fuller after smaller meals. Prescription weight loss medications are most effective when combined with structured diet and physical activity — they are not replacements for lifestyle changes, but powerful tools that support them.
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 Eligibility and How to Access Weight Loss Medication in the UK
To be eligible for prescription weight loss treatment in the UK, you typically need a BMI of 30 or above, or 27 or above if you have weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Access routes differ:
- NHS route: GP referral to a specialist weight management service (tier 3). Availability and waiting times vary significantly by region. Many areas have lengthy waiting lists.
- Private route: Online consultation with a UK-licensed prescriber, prescription issued if clinically appropriate, dispensed by a registered pharmacy. Available without NHS referral.
Start by discussing your weight and fitness goals with your GP. They can assess your individual circumstances, discuss medication options, and advise on the best pathway for you. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses.
- 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 build muscle while using Mounjaro or Wegovy for weight loss?
Yes. These medications support fat loss, not muscle loss. To preserve and build muscle while losing weight, combine prescription medication with structured resistance training (weight training 3–4 times per week), adequate protein intake (1.6–2.2 g per kg body weight), and sufficient calorie deficit (not extreme). Muscle requires active stimulus, so strength training is essential alongside any weight loss medication.
How quickly will I lose weight on prescription weight loss medication?
Weight loss timing varies individually. Most people see noticeable results within 8–12 weeks as doses are escalated. Average loss is around 0.5–1 kg per week, though some lose faster initially. Clinical trials showed maximum average weight loss at 15–20+ weeks on stable doses. Your progress tracker can help you log changes in weight, measurements, and how your clothes fit.
Will my GP prescribe Mounjaro or Wegovy on the NHS?
NHS access depends on your BMI, health conditions, and your region's specialist weight management services. Your GP can refer you to a tier 3 service if you meet criteria, but waiting lists are often long. Many areas have limited availability. Your GP can discuss both NHS and private options with you.
Can I follow a workout plan while taking weight loss injection medication?
Absolutely. In fact, combining prescription medication with consistent exercise produces better results than medication alone. Start with moderate exercise (walking, cycling) immediately, then progress to resistance training as you feel stronger. Stay hydrated, eat adequate protein, and listen to your body. Your GP or a fitness professional can advise on a safe progression plan.
Is prescription weight loss medication permanent, or will I regain weight after stopping?
These medications support weight loss while you take them. Stopping medication doesn't automatically cause weight regain if you've established sustainable habits — regular exercise, balanced diet, and lifestyle changes help maintain results. Some people maintain weight loss long-term without medication; others benefit from ongoing use. Discuss long-term plans with your prescriber.
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.