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
Free tracker included with every download this week
Weight Loss Programs For The Gym
If you're planning a gym-based weight loss program in the UK, combining exercise with the right support can significantly improve your results. Whether you're looking at lifestyle changes alone, NHS-supported weight management, or exploring prescription options like GLP-1 medication, there are several proven approaches available to UK adults. This guide covers the main options and how to find the right program for your goals.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 Loss Options
If you meet eligibility criteria, several prescription weight loss medications are available in the UK to support gym-based programs. Mounjaro (tirzepatide) and Wegovy (semaglutide) are once-weekly injections approved for weight management in UK adults. These work as GLP-1 (or dual GIP/GLP-1) receptor agonists, helping reduce appetite and support feeling fuller after smaller meals—complementing your gym routine by making calorie control easier.
- Mounjaro: Clinical trials showed average weight loss of 15–21% body weight when combined with diet and exercise over 72 weeks.
- Wegovy: STEP trial data showed average weight loss of around 15% body weight at 68 weeks alongside reduced-calorie diet and increased activity.
- Saxenda (liraglutide): A daily GLP-1 injection, also available through NHS and private prescribing for eligible adults.
You're eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Use our free BMI calculator to check your current status.
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 Weight Loss Programs vs. Private Access
In the UK, weight management support is available through both NHS specialist services and private prescribing. The NHS offers tier 3 and tier 4 services, including behaviour change programmes, dietitian support, and prescription medications—but access varies significantly by region and may involve waiting lists. Alternatively, private online prescribing allows eligible adults to access medications like Mounjaro and Wegovy without an NHS referral, following a clinical assessment with a UK-licensed prescriber.
Before starting any weight loss program, speak with your GP about which approach suits you. They can assess your health, discuss eligibility for prescription options, and help you build a sustainable plan combining gym activity, diet, and any recommended medication. Try our GLP-1 weight loss calculator to explore potential outcomes if you're considering prescription 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 use weight loss medication while going to the gym?
Yes. GLP-1 medications like Mounjaro and Wegovy are designed to be used alongside diet and exercise. They work best when combined with a regular gym routine and balanced nutrition. Always inform your GP or prescriber about your exercise plans so they can monitor your progress safely.
What's the difference between NHS and private weight loss programs?
NHS programs are accessed through your GP and specialist weight management services (tier 3/4), often involving multi-disciplinary teams and long-term support—but waiting times vary by region. Private programs allow faster access to prescription medications and consultations through registered online pharmacies, though you pay privately. Both require clinical assessment.
How quickly can I expect weight loss with medication and gym training?
Safe, sustainable weight loss is typically 0.5–1 kg per week. Clinical trial data for GLP-1 medications shows average losses of 15–21% body weight over several months when combined with diet and exercise. Individual results vary significantly based on adherence, starting weight, and personal factors.
Do I need to change my diet if I'm taking prescription weight loss medication?
Yes. Weight loss medications work best alongside a reduced-calorie diet and regular physical activity. They help manage appetite, but they're not a substitute for healthy eating. Many people find that combined with medication, maintaining a calorie deficit becomes easier alongside their gym routine.
How do I find out if I'm eligible for NHS weight loss treatment?
Start by speaking with your GP. You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Your GP can refer you to specialist weight management services in your area, assess your suitability for medication, and discuss your options—including gym-based programs.
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.