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 Lifting Programme — UK Prescription Medication Options
Combining a lifting programme with weight management can boost results, but many people also benefit from prescription medication. In the UK, eligible adults can access GLP-1 and GIP/GLP-1 receptor agonist medications like Mounjaro and Wegovy, which work alongside exercise and diet changes. This guide explains what's available through the NHS and privately, who qualifies, and how to start a conversation with your GP about whether prescription weight loss medication might support your lifting and fitness goals.
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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-Licensed Weight Loss Medications and How They Work
Three main prescription medications are licensed in the UK for weight management:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist; injected once weekly at doses from 2.5 mg to 15 mg. Clinical trials showed participants lost an average of 15–21% of body weight alongside diet and exercise.
- Wegovy (semaglutide) — a GLP-1 receptor agonist; injected once weekly at doses up to 2.4 mg. STEP trials demonstrated average weight loss of around 15% body weight.
- Saxenda (liraglutide) — a GLP-1 receptor agonist; injected daily at doses up to 3 mg. Typically produces slightly lower average weight loss than once-weekly options.
All three medications work by reducing appetite, helping you feel fuller after eating, and supporting better food choices. When combined with a lifting programme and reduced-calorie diet, these medications may enhance overall weight management and body composition improvements. Individual results vary significantly; some people lose more, others less. A prescriber will assess whether prescription weight loss medication is suitable for your specific health profile.
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 Access vs Private Options — How to Get Started
NHS route: Ask your GP for a referral to your local tier 3 specialist weight management service. Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions (high blood pressure, type 2 diabetes, sleep apnoea). NHS prescription is free once approved, though waiting times vary significantly by region.
Private route: You can access prescription weight loss medication through a GPhC-registered online pharmacy following an online clinical assessment — no NHS referral needed. This is faster but involves private cost (typically £129–£320 monthly depending on dose). Whichever route you choose, discuss your lifting programme and fitness goals with your prescriber. They can advise whether medication is appropriate alongside your exercise routine and help monitor your progress.
- 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 lifting weights?
Yes. Prescription weight loss medication like Mounjaro or Wegovy is designed to work alongside exercise and diet. In fact, combining medication with resistance training may support better body composition outcomes — you lose fat while preserving muscle. Always inform your prescriber about your training routine so they can monitor your health and adjust doses if needed.
Will weight loss medication help me build muscle while lifting?
Weight loss medication primarily reduces appetite and fat loss. Muscle building depends on progressive resistance training, adequate protein intake, and sufficient calories for muscle growth. The medication helps create a calorie deficit, which can support fat loss. Your GP or a registered dietitian can help balance your calorie intake to preserve muscle while losing fat.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, high blood pressure, heart disease, sleep apnoea), may be eligible. South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds. Your GP or an online prescriber assesses eligibility based on your individual health profile.
How long does prescription weight loss medication take to work?
Most people begin noticing appetite changes within the first 2–4 weeks. Significant weight loss typically becomes visible after 8–12 weeks of consistent use alongside diet and exercise. Weight loss continues over several months; peak effects are usually seen by 6 months. Your progress tracker can help you log changes and celebrate milestones.
What happens if I stop taking weight loss medication?
Weight loss typically plateaus and may reverse if diet and exercise habits don't support maintenance. This is why lifestyle changes — including your lifting programme — are essential. Medication is a tool to support behaviour change, not a permanent solution. Your prescriber can discuss long-term management options based on your goals and response.
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.