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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Who Qualifies for Weight Loss Injections on the NHS?
If you're struggling with weight management, prescription weight loss injections may be available through the NHS, but eligibility depends on specific criteria. This guide explains who is eligible for weight loss medication under NHS weight management services, the different UK-licensed options available, and how to find out if you qualify for treatment.
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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 Injections and Eligibility Criteria
Three prescription weight loss injections are currently licensed in the UK for adults with overweight or obesity:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist, administered once weekly
- Wegovy (semaglutide) — a GLP-1 receptor agonist, administered once weekly
- Saxenda (liraglutide) — a GLP-1 receptor agonist, administered once daily
To be eligible for prescription weight loss medication on the NHS, you must have a BMI of 30 or above, or a BMI between 27 and 29.9 with at least one weight-related health condition. Weight-related conditions include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, sleep apnoea, or previous cardiovascular disease. Adults of South Asian, Chinese, Black African, or Black Caribbean descent may qualify at lower BMI thresholds (from 27.5 kg/m²) due to higher cardiovascular risk at the same weight. Calculate your personal BMI using our free BMI calculator above to check where you fall.
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: How to Get Weight Loss Injections
NHS access: Available through tier 3 specialist weight management services following a referral from your GP. Availability varies significantly by region, and waiting times can be considerable in many areas. Your GP will assess whether you meet clinical criteria and whether referral is appropriate.
Private access: Available through private prescribers following an online consultation, without requiring an NHS referral. This offers faster access but involves paying privately. Both routes require a clinical assessment confirming you meet eligibility criteria and that weight loss medication is suitable for your individual health.
Start by speaking with your GP about whether you might benefit from prescription weight loss treatment as part of your overall weight management plan.
- 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.
What's the minimum BMI to qualify for weight loss injections on the NHS?
The standard threshold is a BMI of 30 or above. However, if you have weight-related health conditions like type 2 diabetes or high blood pressure, you may qualify at a BMI of 27 or above. Adults from certain ethnic backgrounds (South Asian, Chinese, Black African, or Caribbean) may qualify from a BMI of 27.5 due to higher health risks.
Do weight loss injections work for everyone?
Clinical trials show that GLP-1 and dual GIP/GLP-1 medications help most people lose weight when combined with lifestyle changes, but results vary significantly between individuals. Some people lose more than others. These medications work best alongside a reduced-calorie diet and increased physical activity. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses.
What conditions make me eligible for weight loss injections on the NHS?
Weight-related conditions that may make you eligible include type 2 diabetes, prediabetes, high blood pressure, abnormal cholesterol levels, obstructive sleep apnoea, and a history of heart attack or stroke. You don't need all of these — just one, combined with a BMI between 27 and 29.9, may be enough. Your GP can assess which conditions you have.
How long is the NHS waiting list for weight loss injections?
Waiting times vary significantly by region and NHS area. In some areas, waits exceed 12 months, while others have shorter lists. Specialist tier 3 weight management services manage these referrals. Your GP can tell you the typical wait in your area and discuss whether private options might be worth considering.
Can I get weight loss injections on the NHS without going through my GP?
No — NHS access requires a referral from your GP to a specialist weight management service. Your GP will assess whether you meet eligibility criteria and whether referral is appropriate for your health. If you want faster access without waiting, private prescribing services are available in the UK.
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.