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
52 Week Weight Loss Tracker — UK Prescription Medication Guide
A 52-week weight loss tracker helps you monitor progress over a full year, which is realistic for sustainable weight management in the UK. If you're tracking weight loss on medication, understanding your prescription options—Mounjaro, Wegovy, or Saxenda—is essential. These GLP-1 and GIP/GLP-1 medications are available to eligible adults through NHS specialist services or private prescribing. This guide explains what medication is available, who qualifies, and how to access it. Use our free BMI calculator and GLP-1 weight loss calculator to understand your starting point and projected outcomes.
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 Weight Loss Medications and Eligibility
Three prescription medications are currently licensed in the UK for weight management:
- Mounjaro (tirzepatide) — 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 (semaglutide) — GLP-1 agonist, once-weekly injection, doses 0.25–2.4 mg. Average weight loss approximately 15% body weight in trials.
- Saxenda (liraglutide) — GLP-1 agonist, daily injection, doses 0.6–3 mg. Earlier option with established evidence base.
Eligibility criteria: Adults with a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions (diabetes, high blood pressure, sleep apnoea, cardiovascular disease). For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply (BMI 27.5+). A prescriber will assess your individual suitability.
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.
Accessing Weight Loss Medication — NHS vs Private Route
NHS access: Through tier 3 specialist weight management services. Your GP can refer you, but availability and waiting times vary significantly by region. Many areas have substantial waiting lists; some regions offer rapid access while others take several months.
Private access: Through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. Available without NHS referral, typically faster, and costs range from approximately £129–£320 monthly depending on dose.
Either route requires prescription and clinical assessment—no medication is available without a prescriber's approval. Both approaches work best alongside reduced-calorie diet and increased physical activity. Track your 52-week progress using our free progress tracker to stay accountable.
- 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 get weight loss medication on the NHS?
Yes. If you're eligible (BMI 30+ or 27–29.9 with health conditions), your GP can refer you to a tier 3 specialist weight management service. Availability, waiting times, and exact eligibility vary by region. Contact your local integrated care board to check what's available in your area.
What weight loss can I expect over 52 weeks on Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% of body weight (Mounjaro) and approximately 15% (Wegovy) over similar timeframes, alongside diet and activity changes. Individual results vary significantly—some people lose more, some less. Your GLP-1 weight loss calculator can estimate projections based on your starting weight.
Are weight loss injections safe?
Prescription weight loss medications are licensed and regulated by the MHRA. Side effects are generally mild (nausea, constipation) and often reduce over time. Serious side effects are rare. Always discuss any concerns with your prescriber. They'll assess whether medication is suitable for your personal health.
How do I track my weight properly over 52 weeks?
Weigh yourself once weekly at the same time of day, ideally on the same day. Use our free progress tracker to log weekly weights and visualise trends. Weight naturally fluctuates day-to-day (water, food, hormones), so weekly tracking shows the true pattern better than daily weighing.
Do I need to change my diet if I take weight loss medication?
Yes. Weight loss medication works best with a reduced-calorie diet (typically 500 kcal/day deficit) and increased physical activity. Medication supports appetite control and fullness, but diet remains essential. Your GP or a dietitian can advise on realistic, sustainable eating changes.
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.