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
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NHS Help With Weight Loss — Medication Options Available
If you're struggling with weight management in the UK, prescription medication may be an option worth discussing with your GP. The NHS now offers several clinically proven weight loss treatments for eligible adults, alongside lifestyle changes. This guide explains what's available, who qualifies, and how to access support through the NHS.
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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 Available on the NHS
The NHS prescribes three prescription-only weight management medications for eligible adults: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All three are GLP-1 receptor agonists (Mounjaro also activates GIP receptors), which help regulate appetite and support feeling fuller after smaller meals. Clinical trials show Mounjaro may help users lose approximately 15–21% of body weight, while Wegovy showed average weight loss of around 15%. Saxenda, taken as a daily injection, is also evidence-based for weight management. To qualify, you typically need 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. All medications work best alongside a reduced-calorie diet and increased physical activity.
- Mounjaro: once-weekly injection, doses from 2.5 mg to 15 mg
- Wegovy: once-weekly injection, doses from 0.25 mg to 2.4 mg
- Saxenda: once-daily injection, doses from 0.6 mg to 3 mg
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.
Accessing Weight Loss Support — NHS vs Private Routes
In the UK, NHS prescription weight loss treatment is accessed through specialist tier 3 or tier 4 weight management services, not from your GP directly. Your first step is a conversation with your GP, who will assess your health and may refer you to your local NHS specialist weight management service. Availability varies significantly by region — some areas have established services while others have waiting lists of several months. If you don't want to wait, private online prescribing is also available through UK-licensed prescribers following a clinical assessment, though this involves private costs. Whichever route you choose, a prescriber will evaluate whether the medication is right for you based on your medical history, current medications, and individual health circumstances.
- 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.
How do I know if I'm eligible for NHS weight loss medication?
You're typically eligible if you have a BMI of 30 or above, or 27–29.9 with a weight-related health condition like type 2 diabetes or high blood pressure. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may have lower thresholds. Your GP will assess your individual circumstances during a conversation.
What's the difference between Mounjaro, Wegovy, and Saxenda?
All three are prescription-only GLP-1 medications. Mounjaro is a dual GIP/GLP-1 agonist (once-weekly), Wegovy is a GLP-1 agonist (once-weekly), and Saxenda is a GLP-1 agonist taken daily. Clinical trial data suggests Mounjaro may produce slightly higher average weight loss, but individual results vary significantly. Your GP or prescriber will recommend the most suitable option for you.
How much weight can I expect to lose with these medications?
Clinical trials show average weight loss ranging from approximately 15–21% of body weight depending on the medication and dose, though individual results vary considerably. These results were achieved alongside reduced-calorie diet and increased physical activity. Weight loss is not assured, and your personal outcome will depend on your starting weight, dose, adherence, and lifestyle changes.
How do I start the conversation with my GP about weight loss medication?
Simply book an appointment and explain that you're interested in exploring prescription weight loss options alongside lifestyle changes. Bring your recent weight and height measurements if you have them. Your GP will assess your eligibility, discuss the available medications, and refer you to specialist services if appropriate.
How long does it take to access weight loss medication through the NHS?
This depends on your local NHS area. Some specialist weight management services have short waiting times, while others may have waits of several months. Private routes are typically faster, usually within days to weeks of your online assessment. Ask your GP about typical waiting times in your region when you discuss your options.
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.