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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How to Get an NHS Fat Loss Injection in the UK
Fat loss injections like Mounjaro and Wegovy are available in the UK through both NHS and private routes. If you're interested in weight loss injections, your first step is understanding eligibility and which pathway suits you. The NHS offers access through specialist services, while private options provide faster availability. This guide explains both routes, eligibility requirements, and what to expect from the consultation process.
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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.
Eligibility Criteria for NHS Fat Loss Injections
To access fat loss injections through the NHS, you'll need to meet specific criteria set by NICE and your local Integrated Care Board (ICB). BMI thresholds are the primary measure: you're generally eligible if your BMI is 30 kg/m² or above, or 27 kg/m² or above if you have weight-related health conditions.
- Qualifying health conditions include: type 2 diabetes or prediabetes, high blood pressure, abnormal blood cholesterol, obstructive sleep apnoea, or history of cardiovascular disease
- Ethnicity adjustments: If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply (27.5 kg/m² or above) due to higher health risks at lower weights
- Age requirement: You must be 18 or over
- Other factors: Your GP will assess your overall health, medications, and suitability before referral
Use our free BMI calculator above to check whether your weight falls within the eligible range, and discuss your individual circumstances with your GP.
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 Routes — Which Path Is Right for You?
NHS Route: Your GP refers you to a tier 3 specialist weight management service. Availability varies significantly by region—some areas have well-established services, others have waiting lists of several months or longer. Once referred, a specialist team assesses you and may prescribe weight loss injections as part of a comprehensive programme including diet and lifestyle support. This is free but slower.
Private Route: You book an online consultation with a UK-licensed prescriber, complete a health questionnaire, and receive a prescription if clinically appropriate. A GPhC-registered pharmacy then dispenses the medication. This is faster (typically 1–2 weeks) but costs range from £129–£320+ per month depending on dose. Both routes require genuine clinical assessment—weight loss injections are prescription-only medicines, not over-the-counter products.
- 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 long are NHS waiting lists for weight loss injections?
Waiting times vary by region from weeks to over a year. Contact your local ICB or tier 3 weight management service for specific timelines in your area. Some regions have more established services than others.
Do I need to try diet and exercise first before getting a fat loss injection?
Yes. The NHS expects evidence of previous weight loss attempts. All weight loss injections, whether NHS or private, are prescribed alongside a reduced-calorie diet and increased physical activity—they support lifestyle changes, not replace them.
What's the difference between NHS and private weight loss injections?
The medications are identical (Mounjaro, Wegovy, Saxenda). The differences are: NHS involves GP referral and specialist assessment but is free; private is faster but costs £129–£320+ monthly. Both require prescription and clinical judgment.
Can my GP prescribe weight loss injections directly?
Not usually. GPs typically refer eligible patients to tier 3 specialist weight management services, which then assess and prescribe. Some integrated care systems allow GP prescribing after specialist initiation, but this varies by region.
What happens in a private weight loss injection consultation?
You complete a health questionnaire covering medical history, current medications, allergies, and lifestyle. A UK-licensed prescriber reviews this, may ask follow-up questions, then decides if the medication is safe for you. If approved, a prescription is issued to a pharmacy.
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.