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 and Giving Up Alcohol — What You Need to Know
Giving up or reducing alcohol is one of the most effective changes you can make for weight management in the UK. Alcohol contains significant calories with little nutritional benefit, and reducing intake can support sustainable weight loss. However, if you're struggling with weight despite lifestyle changes, prescription weight management options may help. For eligible adults, NHS services and private prescribers offer clinically approved medications alongside diet and exercise support.
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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
For adults in the UK meeting eligibility criteria, prescription weight management medications are available through NHS specialist services or private prescribers. The main options are Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are GLP-1 receptor agonist medications (Mounjaro is a dual GIP/GLP-1 agonist) that may help reduce appetite and support feeling fuller after smaller meals, making dietary changes like reducing alcohol intake easier to maintain.
- Mounjaro: Once-weekly injection, 2.5–15 mg doses. Clinical trials showed average weight loss of 15–21% body weight over 72 weeks.
- Wegovy: Once-weekly injection, 0.25–2.4 mg doses. Average weight loss approximately 15% body weight in clinical trials.
- Saxenda: Daily injection, 0.6–3 mg doses. Longest-established option in the UK.
All are prescription-only and require clinical assessment to determine suitability based on BMI, health conditions, and individual circumstances.
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 and Next Steps
NHS prescription weight loss treatment is available through tier 3 specialist weight management services, typically requiring GP referral. Access and waiting times vary significantly by region. Private access is available through GPhC-registered online prescribers following a clinical consultation, usually without NHS referral. Eligibility generally requires a BMI of 30 kg/m² or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. South Asian, Chinese, Black African, and Black Caribbean adults may have lower BMI thresholds due to higher health risks at lower weights. Your GP is the best starting point — they can assess your individual situation and discuss whether prescription medication alongside lifestyle changes like reducing alcohol is appropriate for you.
- 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.
Will giving up alcohol alone help me lose weight?
Reducing or giving up alcohol can significantly support weight loss, as alcohol is calorie-dense and often high in sugar. A standard glass of wine contains around 100–130 calories, and beer 150–180 calories, with no nutritional benefit. Removing these calories typically results in gradual weight loss, especially when combined with a healthy diet and physical activity. However, if you've made lifestyle changes without reaching your goals, prescription weight management may help.
Can I take weight loss medication like Mounjaro or Wegovy if I drink alcohol?
Alcohol and weight loss medications are not directly contraindicated, but alcohol adds empty calories that work against weight loss goals and may worsen side effects like nausea. Your prescriber will discuss alcohol use during your clinical assessment. Most guidance recommends minimising alcohol while taking weight loss medication to maximise results and reduce side effects.
How do I check if I'm eligible for prescription weight loss medication in the UK?
You're potentially eligible if your BMI is 30 kg/m² or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Use our free BMI calculator on this page to check your BMI instantly. For a proper assessment, contact your GP, who can refer you to NHS specialist services, or consult a private prescriber online who will conduct a clinical review.
What's the difference between NHS and private prescription weight loss in the UK?
NHS prescription weight loss is available through tier 3 specialist weight management services with a GP referral, though waiting times and availability vary by region. Private prescribing is available through online clinics registered with the GPhC, without NHS referral, and typically faster access. Both require clinical assessment; private treatment involves out-of-pocket costs (typically £129–£320 monthly depending on medication and dose).
Can the GLP-1 weight loss calculator on MyWeightCheck show me potential results?
Yes, our free GLP-1 weight loss calculator can help estimate projected weight loss at different Mounjaro and Wegovy doses, based on clinical trial data. Enter your current weight above to see potential outcomes at various doses. Remember that individual results vary significantly, and all estimates assume the medication is used alongside a reduced-calorie diet and increased physical activity, much like reducing alcohol intake supports overall weight management efforts.
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.