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
Alcohol and Weight Loss — What You Need to Know
Alcohol is high in calories and can undermine weight loss efforts, but the relationship between drinking and weight management is more nuanced than simply avoiding alcohol entirely. If you're struggling with weight and considering your options, UK-licensed prescription weight loss medications may help alongside lifestyle changes. This guide explains how alcohol affects weight loss and what prescription weight management options are available to eligible adults in the UK.
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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 Prescription Weight Loss Options
If you're looking to lose weight and manage your health, the UK has several prescription-only weight loss medications available for eligible adults. These are licensed by the MHRA and prescribed through the NHS or private clinical assessments.
- Mounjaro (tirzepatide) — A once-weekly injection that activates dual GIP and GLP-1 pathways. Clinical trials showed average weight loss of 15–21% body weight over 72 weeks, alongside a reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — A once-weekly GLP-1 injection. The STEP-1 trial demonstrated average weight loss of approximately 15% body weight at the maximum dose.
- Saxenda (liraglutide) — A daily GLP-1 injection option, though less commonly prescribed than Mounjaro or Wegovy.
Eligibility typically requires a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Individual results vary, and these medications work best alongside dietary changes and increased physical activity.
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.
How to Access Weight Loss Treatment in the UK
NHS route: You can ask your GP for a referral to a specialist weight management service (tier 3). Access varies significantly by region and waiting times can be lengthy. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results.
Private route: Prescription weight loss medications are available through private online consultations with UK-licensed prescribers. A clinical assessment determines whether medication is suitable for you. Our GLP-1 weight loss calculator can help you estimate potential weight loss at different doses.
Whichever path you choose, a prescriber will assess your individual health, medications, and eligibility before issuing a prescription. Your GP can also advise whether prescription weight loss treatment is appropriate for your situation.
- 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.
Does alcohol affect weight loss?
Yes. Alcohol is calorie-dense (7 calories per gram) and can contribute significantly to daily calorie intake. It may also reduce motivation to stick to healthy eating habits and can increase appetite. Reducing or eliminating alcohol is often recommended as part of a weight management plan, alongside increased physical activity and dietary changes.
How do GLP-1 injections like Wegovy and Mounjaro work?
These are receptor agonist medications that activate natural hormone pathways in the body. They may help reduce appetite, increase feelings of fullness, and support healthier food choices. Mounjaro uses a dual mechanism (GIP and GLP-1), while Wegovy uses GLP-1 alone. Both are prescription-only and require clinical assessment before prescribing.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above are generally eligible. Those with a BMI of 27–29.9 may be eligible if they have weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, and Black Caribbean adults may have access at lower BMI thresholds due to higher health risks at those levels.
Can I get weight loss injections through the NHS?
Yes, but access is through specialist tier 3 weight management services, not standard GP prescriptions. You need a GP referral and assessment. NHS availability varies significantly by region, and waiting lists can be very long. Private prescription options are also available through online clinical assessments with UK-licensed prescribers.
What does the NHS recommend for healthy weight loss?
The NHS recommends losing weight at a rate of 0.5 to 1 kg (1–2 lbs) per week as sustainable and safe. This typically requires a calorie deficit of around 500 calories per day, achieved through dietary changes and increased physical activity. Our BMI calculator and weight converter can help you track your starting point and set realistic targets.
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.