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
Weight Loss Injections: NHS Cost and UK Availability
Weight loss injections are prescription-only medicines available to eligible adults in the UK through both NHS and private routes. The cost varies significantly depending on whether you access treatment through the NHS or privately, and availability differs across regions. This guide explains your options, what you might pay, and how to find out if you qualify for prescription weight management 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.
UK-Licensed Weight Loss Injections and Eligibility
Three GLP-1 and GIP/GLP-1 receptor agonist medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All are prescription-only and require a clinical assessment before being prescribed.
To be eligible, you typically need a BMI of 30 or above, or a BMI of 27–29.9 with at least one weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, or cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds (BMI 27.5+). Use our free BMI calculator to check where you stand. Weight loss injections work best when combined with dietary changes and increased physical activity — they are not a replacement for lifestyle changes. Individual results vary significantly, and clinical trials have shown average weight loss ranging from 15–21% of body weight depending on the medication and dose.
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: Costs and Availability
NHS access: Weight loss injections are available through NHS tier 3 specialist weight management services following a GP referral. There is no direct cost to you if prescribed on the NHS — treatment is free. However, availability varies significantly by region, and waiting lists can be several months to over a year in many areas. NICE has approved tirzepatide (Mounjaro) for NHS use, though regional ICBs control local implementation.
Private access: You can obtain a prescription through a GPhC-registered online pharmacy following a digital clinical assessment — no NHS referral needed. Private costs typically range from £129 to £320+ per month depending on the medication, dose, and provider. Start by asking your GP about NHS options; if waiting times are long or you're not eligible, discuss private routes. Track your progress with our free progress tracker once you begin 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.
How much do weight loss injections cost on the NHS?
Weight loss injections prescribed through the NHS are free — there is no direct cost to you. However, availability depends on your local NHS integrated care board (ICB), and you will need a referral from your GP to a tier 3 specialist weight management service. Waiting lists can be lengthy.
What is the typical private cost for weight loss injections in the UK?
Private costs vary but typically range from £129 to £320+ per month, depending on the medication (Mounjaro, Wegovy, or Saxenda), the dose, and the provider. Some online pharmacies offer different pricing structures. Costs may decrease at higher doses due to bulk pricing.
What is the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed average weight loss of 15–21% with Mounjaro and approximately 15% with Wegovy. Both are once-weekly injections. Individual results vary, and either may be more suitable depending on your health profile.
Am I eligible for weight loss injections on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with a weight-related health condition such as type 2 diabetes or high blood pressure. Lower BMI thresholds apply for certain ethnic groups. Speak to your GP, who can refer you to a specialist weight management service for assessment. Use our BMI calculator to check your starting point.
How long does it take to get weight loss injections on the NHS?
This varies widely by region. Some areas offer appointments within weeks, while others have waiting lists of 6–18 months or longer. Private routes are typically faster — you can usually get a prescription within days of a digital assessment — though you will pay for the medication.
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.