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
How to Get Fat Loss Injections in the UK
Fat loss injections (also called weight loss jabs or slimming injections) are prescription-only medicines available in the UK through two main routes: NHS specialist weight management services and private online prescribing. Access depends on your BMI, health conditions, and which route you choose. NHS access typically involves a GP referral and waiting list, while private access is faster but comes at a cost. This guide explains eligibility criteria, what the consultation process involves, and how to get started with GLP-1 weight loss injections in the UK.
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.
Eligibility for Fat Loss Injections — Who Can Access Them
To access weight loss injections in the UK, you must meet specific NHS eligibility criteria. Adults with a BMI of 30 or above can access prescription slimming injections. Adults with a BMI of 27 to 29.9 may also be eligible if you have at least one weight-related health condition, such as type 2 diabetes, prediabetes, high blood pressure, abnormal cholesterol levels, obstructive sleep apnoea, or a history of heart disease or stroke.
Lower BMI thresholds apply if you are of South Asian, Chinese, Black African, or Black Caribbean heritage — eligibility may begin at a BMI of 27.5 or above. Your age must be 18 or over. Use our free BMI calculator above to check your current BMI and understand where you fall on the eligibility scale.
You cannot access fat loss injections if you:
- Are pregnant, planning pregnancy, or breastfeeding
- Have a severe allergy to the medication ingredients
- Have untreated or severe gastroparesis (stomach emptying problems)
- Have a personal or family history of medullary thyroid cancer
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 access: Your GP can refer you to a tier 3 specialist weight management service. These services assess your eligibility, provide lifestyle support, and prescribe fat loss injections if appropriate. However, NHS waiting lists are lengthy in many areas — ranging from several months to over a year depending on your region. Once prescribed, NHS prescriptions cost £11.65 per item (standard prescription charge).
Private access: You can consult a UK-licensed prescriber online without a GP referral. The consultation typically takes 10–15 minutes and covers your medical history, current medications, and weight loss goals. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy within 24–48 hours. Private costs range from £129–£320 per month depending on dose and provider. Private access is faster but requires upfront payment.
Track your progress with our free progress tracker once you start treatment.
- 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 exactly are fat loss injections and how do they work?
Fat loss injections are prescription medicines containing GLP-1 receptor agonists (like semaglutide in Wegovy) or dual GIP/GLP-1 agonists (like tirzepatide in Mounjaro). They work by mimicking natural gut hormones that signal fullness to the brain, reduce appetite, and slow how quickly food leaves the stomach. They're used alongside diet and exercise for weight management in eligible UK adults.
Can I get fat loss injections on the NHS?
Yes. Your GP can refer you to a specialist tier 3 weight management service, where prescribers assess your eligibility and prescribe if appropriate. NHS access is free (standard prescription charge applies), but waiting lists can be very long — often 6–12 months or more depending on your region. Availability varies significantly by local integrated care board.
How quickly can I access private fat loss injections?
Private consultations can often be booked within days. Once approved by the prescriber, your prescription is typically dispensed within 24–48 hours by a GPhC-registered pharmacy. The entire process from booking to receiving your first injection can happen within 1–2 weeks, much faster than NHS routes.
What happens during a private consultation for fat loss injections?
A licensed UK prescriber reviews your medical history, current medications, BMI, and weight loss goals. They assess whether slimming injections are suitable for you and explain potential side effects. If approved, they issue a prescription to a pharmacy. The consultation is usually done online via video or telephone and takes 10–15 minutes.
Are fat loss injections covered by insurance in the UK?
Most UK private health insurance policies do not cover weight loss injections because they're considered elective treatments rather than medical necessities. Some policies may cover them if prescribed for an underlying health condition like type 2 diabetes. Check your specific policy or contact your insurer directly. NHS provision is free (prescription charge only) for eligible patients.
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.