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 Gym Routine & UK Prescription Options
A structured gym routine combined with lifestyle changes can support sustainable weight loss. In the UK, prescription weight management medications are also available for eligible adults. These include GLP-1 receptor agonists like Mounjaro and Wegovy, which work alongside exercise and dietary changes — not instead of them. This guide covers how to approach weight management through gym routines and explains the prescription weight loss options available through the NHS and private prescribing in the UK.
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
For adults struggling with weight management despite exercise and diet changes, prescription medications are available in the UK. Mounjaro (tirzepatide) and Wegovy (semaglutide) are dual and single GLP-1 receptor agonists respectively, licensed for weight management in UK adults. Saxenda (liraglutide) is also available but requires daily injections rather than weekly ones.
Eligibility typically requires a BMI of 30 kg/m² or above, or 27 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Clinical trial data shows prescription weight loss medication can help participants lose an average of 15–21% of their body weight alongside reduced-calorie diet and increased physical activity — though individual results vary significantly.
These are prescription-only medicines that require clinical assessment before being prescribed. A prescriber will evaluate your personal health history, current medications, and suitability before dispensing.
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 vs Private Access in the UK
NHS access: Prescription weight loss medication is available through tier 3 specialist weight management services. Your GP can refer you, though waiting lists vary significantly by region and may be several months to years in some areas.
Private access: Available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. This typically offers faster access without NHS referral, though costs vary by dose (usually £129–£320 per month).
To find out if you're eligible, speak with your GP first — they can discuss your individual circumstances, BMI, and health conditions. Use our free BMI calculator above to check your starting point, then have a conversation with your healthcare provider about the best approach for your weight management journey.
- 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 a gym routine instead of weight loss medication?
Yes — many people achieve sustainable weight loss through exercise, diet, and lifestyle changes alone. A structured gym routine combined with a calorie deficit can be very effective. However, if you've tried these approaches and struggled, prescription medication may be an option to discuss with your GP. Medication works alongside exercise and diet, not as a replacement.
What type of gym routine supports weight loss?
Combining cardiovascular exercise (running, cycling, swimming) with resistance training is most effective. The NHS recommends at least 150 minutes of moderate aerobic activity weekly, plus muscle-strengthening activities twice weekly. A personal trainer can help tailor a routine to your fitness level and goals.
How quickly will prescription weight loss medication work?
Most people notice changes within 4–12 weeks, though this varies. Mounjaro and Wegovy require gradual dose escalation over several weeks. Results depend on your individual metabolism, adherence to the medication, and lifestyle changes. Your prescriber will monitor progress and adjust doses as needed.
Are prescription weight loss injections available on the NHS?
Yes — NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for NHS specialist weight management services. However, access varies significantly by region and waiting lists can be long. Your GP can refer you to your local tier 3 service, but private options may be faster.
What happens if I stop taking prescription weight loss medication?
Weight may return if lifestyle changes are not maintained. These medications work best as part of a comprehensive approach including exercise and diet. Your prescriber will discuss a plan for stopping medication and maintaining progress through gym routines and healthy eating habits long-term.
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.