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
NHS Criteria for Weight Loss Injections in the UK
To access weight loss injections through the NHS in the UK, you need to meet specific BMI and health criteria. Most people qualify if they have a BMI of 30 or above, or a BMI of 27 to 29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or heart disease. However, NHS access is limited — weight loss injections are prescribed through specialist weight management services, not standard GP practice, and waiting lists can be lengthy in many regions. Understanding your eligibility and local NHS options is the first step toward accessing this prescription weight loss 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.
NHS Weight Loss Injection Eligibility
Standard eligibility criteria: You may qualify for prescription weight loss injections through the NHS if you have:
- A BMI of 30 kg/m² or above (obesity)
- A BMI of 27–29.9 kg/m² (overweight) AND at least one weight-related health condition
Qualifying health conditions include: Type 2 diabetes or prediabetes, high blood pressure, abnormal blood fats (dyslipidaemia), obstructive sleep apnoea, or a history of heart attack or stroke. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply — eligibility can start at a BMI of 27.5 or above, reflecting higher cardiovascular risk at lower BMI levels. You can check your personal BMI using our free BMI calculator to understand where you fall within NHS categories. Your GP can then assess whether you meet full criteria for referral to a specialist weight management service.
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.
How to Access Weight Loss Injections on the NHS
Weight loss injections are not prescribed directly by most GPs — they are accessed through specialist tier 3 or tier 4 weight management services, typically based in hospitals or specialist centres. Your GP must refer you to these services, and you will then be assessed by a multidisciplinary team. However, NHS availability varies significantly by region. Some areas have good access; others have waiting lists stretching months or even years. If your local NHS service has limited availability, you may explore private prescription routes through GPhC-registered online pharmacies, which offer faster access following a clinical assessment. Track your weight loss progress with our free progress tracker while waiting for NHS assessment or managing your weight independently.
- 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 BMI do I need to qualify for NHS weight loss injections?
You need a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, heart disease, etc.). For some ethnic groups, lower thresholds apply — discuss with your GP to clarify your eligibility based on your background.
How long are NHS waiting lists for weight loss injections?
Waiting times vary significantly by region and local ICB. Some areas offer relatively quick access; others have waiting lists of many months. Contact your local NHS weight management service for typical waiting times in your area.
Can my GP prescribe weight loss injections directly?
Most GPs cannot prescribe weight loss injections — these are available only through specialist tier 3/4 weight management services. Your GP can refer you to these services if you meet criteria, but the specialist team will make the final prescription decision.
Are there alternative routes to weight loss injections if NHS waiting times are long?
Yes. Private prescription pathways are available through GPhC-registered online pharmacies. Following a clinical assessment by a UK-licensed prescriber, you can access medications like Wegovy or Mounjaro privately, typically with faster availability than NHS routes.
What if my BMI is 29 — can I still access weight loss injections on the NHS?
If your BMI is 27–29.9, you may qualify if you have a weight-related health condition (diabetes, high blood pressure, heart disease, sleep apnoea, or cardiovascular history). Your GP can assess whether your specific health situation meets criteria for referral.
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.