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 Weight Loss Programme With UK Medication Options
A gym weight loss programme works best when combined with proper nutrition and, for some people, medical support. If you're struggling to lose weight through exercise and diet alone, prescription weight management medication may be an option. In the UK, several GLP-1 medications are now available for eligible adults, alongside your fitness efforts. This guide explains which medications are licensed for weight management in the UK, who might qualify, and how to find out if treatment could help support your 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-Licensed Prescription Weight Management Options
Three prescription medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All three work by activating GLP-1 hormone pathways to help reduce appetite and support feeling fuller after smaller meals.
- Mounjaro: Dual GIP and GLP-1 agonist, once-weekly injection, doses 2.5–15 mg. Clinical trials showed average weight loss of 15–21% body weight.
- Wegovy: GLP-1 agonist, once-weekly injection, maximum dose 2.4 mg. STEP trial data showed approximately 15% average weight loss.
- Saxenda: GLP-1 agonist, daily injection, maximum dose 3 mg. Longer-established option with robust trial evidence.
All are prescription-only medicines requiring clinical assessment. Individual results vary, and all are most effective when combined with reduced-calorie diet and increased physical activity—including your gym weight loss programme.
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.
Who Is Eligible and How to Access Treatment
In the UK, adults may be eligible for prescription weight management medication if they have a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, and Black Caribbean adults have lower eligibility thresholds (BMI 27.5+) due to higher health risks at lower weights.
NHS access: Referral to a tier 3 specialist weight management service through your GP. Availability varies by region; waiting lists can be lengthy. Private access: Online consultation with a UK-licensed prescriber; no NHS referral needed. Speak with your GP first to discuss options and whether medication might complement your gym routine and weight management UK goals.
- 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 use weight loss medication while doing gym training?
Yes. GLP-1 medications work best alongside regular exercise and a reduced-calorie diet. Your gym weight loss programme, combined with medication, may produce better results than either approach alone. Always inform your prescriber about your fitness routine and any other medications.
How much weight can I expect to lose on prescription medication?
Clinical trials showed average weight loss of 15–21% body weight with Mounjaro and approximately 15% with Wegovy—but individual results vary significantly. Results depend on your starting weight, adherence to diet and exercise, and individual response. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses.
What's the difference between NHS and private prescription weight loss?
NHS access is through specialist services (tier 3), often with waiting lists; private access is through online consultants with no referral needed. Both require prescription and clinical assessment. NHS may be free; private prescriptions have a cost. Speak to your GP about which route suits you.
Can I get weight loss injections through the NHS?
Yes, if eligible and referred to a specialist weight management service. NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for NHS use, but availability and waiting times vary by region. Ask your GP about local tier 3 services and eligibility criteria.
Is prescription medication necessary for a successful gym weight loss programme?
No. Many people lose weight through diet and exercise alone. However, for those who find it difficult, medication may provide additional support. Calculate your BMI using our free BMI calculator to see where you stand, then discuss options with your GP.
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.