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
Weekend Weight Loss — UK Prescription Options and Strategies
Weekend weight loss can be challenging, especially when routine changes and social eating interrupt your week. While sustainable weight management happens year-round, prescription medications available in the UK can support your progress alongside lifestyle changes. This guide covers UK-licensed weight loss medication options, eligibility criteria, and practical weekend strategies to help you stay on track with your weight management journey.
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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 Weight Loss Medications for Weight Management
Three prescription-only medications are licensed in the UK for weight management in eligible adults. Mounjaro (tirzepatide) is a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist, with clinical trials showing average weight loss of 15–21% of body weight. Wegovy (semaglutide) is also a once-weekly GLP-1 injection, with trials demonstrating approximately 15% average weight loss. Saxenda (liraglutide) is a daily GLP-1 injection option.
To be eligible for prescription weight loss medication in the UK, you typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions including type 2 diabetes, high blood pressure, or sleep apnoea. People of South Asian, Chinese, Black African, or Black Caribbean heritage may qualify at lower BMI thresholds (27.5+). All three medications are prescribed alongside a reduced-calorie diet and increased physical activity — medication alone is not sufficient for sustainable results.
- Requires clinical assessment from a UK-licensed prescriber
- Individual results vary significantly
- Often used as part of comprehensive weight management approach
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 Access vs Private Routes — Finding the Right Option for You
In the UK, prescription weight loss medication is available through two routes. NHS access comes through specialist tier 3 or 4 weight management services, typically requiring a GP referral. However, NHS availability varies significantly by region, and waiting lists can be substantial — sometimes months to years depending on your local integrated care board (ICB). Private access is available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber, without requiring NHS referral.
To find out if you're eligible, start by speaking with your GP about weight management support. They can assess your health, discuss medication options, or refer you to specialist services if appropriate. Our free BMI calculator above can help you understand your current BMI category and whether you might meet eligibility thresholds. You can also use our GLP-1 weight loss calculator to explore potential outcomes at different medication doses based on clinical trial data.
- 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 lose weight over the weekend with medication?
Weight loss medications like Mounjaro and Wegovy work over weeks and months, not hours or days. However, they can support consistent progress throughout the week, including weekends. Sustainable weekend weight loss comes from combining medication (if eligible) with reduced-calorie eating and physical activity during the weekend period.
How do I know if I'm eligible for weight loss medication in the UK?
You're typically eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes or high blood pressure. Lower thresholds apply for people of South Asian, Chinese, Black African, or Caribbean heritage. Your GP can assess your individual eligibility and discuss options.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 injection with average trial weight loss of 15–21%, whilst Wegovy (semaglutide) is a GLP-1-only injection with approximately 15% average weight loss. Both are once-weekly. Choice depends on clinical assessment, individual factors, and prescriber recommendation.
Can I get weight loss medication on the NHS or do I need to go private?
Both routes exist in the UK. NHS access is through specialist weight management services (tier 3/4) via GP referral, though availability varies by region and waiting lists can be long. Private access is available through GPhC-registered pharmacies following an online clinical assessment — typically faster but involves private costs.
What should I do if I want to explore weight loss medication options?
Start by speaking with your GP about weight management support. They can assess your health, discuss medication eligibility, and either prescribe (if appropriate) or refer you to specialist NHS services. You can also explore private prescribing through registered online pharmacies. Our BMI calculator and GLP-1 weight loss calculator can help you understand your starting point.
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.