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 Programs in the UK
Gym weight loss programs combine structured exercise with dietary guidance to help adults lose weight sustainably. In the UK, these programs often work alongside NHS weight management services or private fitness providers. For many people, gyms offer a supportive environment and expert coaching, but some adults may also benefit from prescription weight loss medication if eligible. This guide covers how gyms fit into a comprehensive weight management strategy, and explores medication options available through the UK health system. Our free BMI calculator can help you understand your starting point before beginning any programme.
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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 Weight Loss Options: Exercise, Diet, and Medication
Gym-based weight loss programs typically combine cardiovascular exercise, strength training, and nutritional counselling. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results, which usually requires a calorie deficit of around 500 kcal per day alongside regular physical activity.
For adults meeting certain criteria, prescription weight loss medication is now available in the UK. Three main options are licensed for weight management:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist, given as a once-weekly injection. Clinical trials showed average weight loss of 15–21% of body weight.
- Wegovy (semaglutide) — a GLP-1 receptor agonist, also a once-weekly injection. Studies demonstrated approximately 15% average weight loss alongside diet and exercise.
- Saxenda (liraglutide) — a daily GLP-1 injection, typically used when weekly options are unsuitable.
These are prescription-only medicines. Weight loss injections work best when combined with gym attendance, dietary changes, and increased physical activity—medication supports your efforts, not replacing them.
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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 vs Private Access: How to Start
In the UK, you can access weight loss medication through two routes. NHS access is via referral to a specialist tier 3 or tier 4 weight management service, usually requested by your GP. However, NHS availability and waiting times vary significantly by region. Private access is available through GPhC-registered online prescribing services following a clinical assessment—no NHS referral needed, though costs apply (typically £129–£320 per month depending on dose).
To find out if you're eligible, check your BMI using our free BMI calculator above. Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (such as high blood pressure, type 2 diabetes, or sleep apnoea), may qualify. Start by speaking with your GP about weight management options suitable for you, or explore private prescribing if you prefer faster access.
- 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 gym weight loss programs without medication?
Yes. Many people successfully lose weight through gym attendance, dietary changes, and increased physical activity alone. The NHS recommends this as the first approach. However, if you've tried lifestyle changes without sufficient results, or if you meet eligibility criteria, prescription weight loss medication may be an additional option worth discussing with your GP.
Are gym weight loss programs available through the NHS?
The NHS offers free tier 1 and tier 2 weight management support, including digital programmes and community-based services. Some NHS weight management services are gym-based or include gym referrals. However, access varies by region and some areas have waiting lists. Your GP can tell you what's available in your local area.
What's the difference between gym programs and weight loss medication?
Gym programs focus on exercise and lifestyle change. Weight loss medication (like Mounjaro or Wegovy) works by reducing appetite and food cravings, helping you eat less. They work best together—medication supports your gym efforts, not replaces them. Both require sustained dietary changes and physical activity.
How much weight can I expect to lose with a gym program and medication?
Individual results vary significantly. In clinical trials, GLP-1 medications showed average weight loss of 15–20% of body weight over several months, but this depends on the dose, your starting weight, diet adherence, and exercise consistency. A gym program alone typically supports 0.5–1 kg loss per week. Always discuss realistic expectations with your GP or prescriber.
What weight loss medication is available on the NHS?
Tirzepatide (Mounjaro) and semaglutide (Wegovy) are now approved for NHS prescription through specialist weight management services, though regional availability varies and waiting times can be long. Private prescribing is faster but involves a cost. Your GP can advise whether you meet NHS criteria and discuss local options.
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.