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 Smoothies and Prescription Medication in the UK
Weight loss smoothies can be a helpful part of a healthy diet, but for many people seeking significant weight loss, prescription medication may offer additional support. The UK has several licensed weight management options available through the NHS and privately. This guide explains how smoothies fit into a weight loss plan, the prescription medications available in the UK, and how to find out if you're eligible for treatment.
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 Prescription Weight Loss Options
Three prescription-only medications are currently licensed in the UK for weight management in eligible adults. Mounjaro (tirzepatide) is a once-weekly injection that works by activating two hormone pathways — GIP and GLP-1 — and in clinical trials helped participants lose an average of 15–21% of their body weight. Wegovy (semaglutide) is another once-weekly injection that activates GLP-1, with clinical trial results showing approximately 15% average weight loss. Saxenda (liraglutide) is a daily injection option. All three require a prescription following a clinical assessment.
You may be eligible if you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply. Use our free BMI calculator to check where you fall, and our GLP-1 weight loss calculator to estimate potential outcomes at different doses. These medications work alongside diet and exercise — not instead of them.
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 Prescription Weight Loss
NHS access is available through specialist tier 3 weight management services, typically after referral from your GP. However, waiting lists are often very long, and access varies significantly by region. Private prescription access is faster — you can have an online consultation with a UK-licensed prescriber and receive a prescription within days if clinically appropriate. Costs typically range from £129–£320 per month depending on the dose and provider.
Your GP can discuss your eligibility, recommend NHS services in your area, or advise whether private prescription weight loss treatment is suitable for you. Track your progress with our free progress tracker, and use the weight converter to monitor changes across kg, stone, and pounds. Remember: individual results vary, and these medications are most effective alongside a reduced-calorie diet and increased physical activity.
- 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 weight loss smoothies alone help me lose significant weight?
Weight loss smoothies can support weight management when part of a calorie-deficit diet, but results are usually modest without other lifestyle changes. For significant weight loss, combining smoothies with reduced overall calories, exercise, and potentially prescription medication (if eligible) is more effective. Talk to your GP about your weight loss goals.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes or high blood pressure, may be eligible. Lower thresholds apply for South Asian, Black African, Chinese, and Black Caribbean adults. A GP or licensed prescriber will assess your individual eligibility following a clinical consultation.
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections, but Mounjaro activates two hormone pathways (GIP + GLP-1) while Wegovy activates one (GLP-1). In clinical trials, Mounjaro showed slightly higher average weight loss (15–21% vs ~15%), but results vary between individuals. Your prescriber will recommend which is most suitable for you.
How much weight can I expect to lose with prescription medication?
Clinical trials show average weight loss of 15–21% of body weight over 68–72 weeks, alongside a reduced-calorie diet and physical activity. However, individual results vary significantly. Some people lose more, others less. Use our GLP-1 weight loss calculator to estimate potential outcomes based on current dose recommendations.
Can I get prescription weight loss medication through the NHS?
Yes, through specialist tier 3 weight management services. Access is via GP referral, but waiting times can be months to years depending on your region. Private prescription options offer faster access but require payment. Contact your GP to discuss NHS availability in your area or explore private options with a licensed UK prescriber.
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.