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
Best Weight Loss Milk and UK Weight Management Options
While milk choice can play a small role in weight management, the most effective approach for many adults in the UK involves prescription weight loss medication alongside lifestyle changes. If you're looking to lose weight and have a BMI of 30 or above, or 27 and above with weight-related health conditions, you may be eligible for prescription weight loss treatment through the NHS or privately. This guide explains your options, how to check eligibility, and why speaking to your GP is the important first step toward sustainable weight loss 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-Licensed Prescription Weight Loss Options
Three prescription medications are currently licensed in the UK for weight management alongside diet and exercise: Mounjaro (tirzepatide), a once-weekly injection that activates dual GIP and GLP-1 pathways; Wegovy (semaglutide), a once-weekly GLP-1 injection; and Saxenda (liraglutide), a once-daily injection. Clinical trials have shown that these medications may help with weight loss when used as part of a comprehensive weight management approach. For example, Mounjaro participants in clinical trials lost an average of 15–21% of body weight, though individual results vary significantly. These are prescription-only medicines that require a clinical assessment before they can be prescribed. Eligibility depends on your BMI, weight-related health conditions, and individual health factors assessed by a qualified prescriber.
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
Access to prescription weight loss medication in the UK varies depending on your circumstances. NHS access is through specialist tier 3 or 4 weight management services, typically following a referral from your GP—waiting times vary significantly by region. Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber, and doesn't require an NHS referral. To find out if you're eligible, start by speaking to your GP about your weight management goals. They can discuss your options, assess your individual health needs, and either refer you to NHS specialist services or advise on private options. Use our free BMI calculator to understand your current BMI category, then take that information to your appointment.
- 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 the type of milk I drink affect weight loss?
Milk choice has a minor impact on weight loss. Skimmed or semi-skimmed milk contain fewer calories than full-fat options, but the difference is small. Weight loss is primarily determined by overall calorie intake, physical activity, and for many people, prescription medication alongside lifestyle changes. Focus on total diet rather than single foods.
What's the difference between Mounjaro and Wegovy for weight loss in the UK?
Both are prescription-only injections, but Mounjaro (tirzepatide) activates two hormone pathways (GIP and GLP-1), while Wegovy (semaglutide) activates one (GLP-1). Clinical trials showed Mounjaro may achieve slightly higher average weight loss (up to 21% vs 15% body weight). Both require clinical assessment. Your prescriber will recommend which is suitable for you.
Am I eligible for prescription weight loss medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27 or above with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). Eligibility varies by region. Contact your GP to discuss referral to NHS specialist weight management services in your area.
How do I start the process of getting prescription weight loss treatment?
Book an appointment with your GP and discuss your weight management goals and any weight-related health conditions. They can assess your eligibility and either refer you to NHS specialist services or advise on private options. You'll need a clinical assessment before any prescription is issued—this ensures the medication is safe and appropriate for you.
Can I use our GLP-1 weight loss calculator to estimate potential results?
Yes. Our free GLP-1 weight loss calculator can help you estimate potential weight loss at different doses based on clinical trial data. However, individual results vary significantly. Always discuss realistic expectations with your prescriber—they'll give you personalised guidance based on your health profile and circumstances.
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.