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 Much Are Weight Loss Injections in the UK?
Weight loss injections (GLP-1 medications) are available in the UK through both NHS specialist services and private prescribing routes, with costs varying significantly depending on the medication, dose, and where you access treatment. On the NHS, they are typically free once prescribed through tier 3 weight management services, though availability and waiting times vary by region. Through private prescribing, costs range from approximately £129 to £320 per month depending on the specific medication and dose you're prescribed. Understanding both routes and their costs can help you make an informed decision about your weight management options.
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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.
Private Weight Loss Injection Costs in the UK
Private weight loss injections are available through GPhC-registered online pharmacies following an online clinical assessment from a UK-licensed prescriber. Mounjaro (tirzepatide) typically costs between £180 and £320 per month depending on your dose, with starting doses (2.5 mg) at the lower end and maximum doses (15 mg) at the higher end. Wegovy (semaglutide) costs approximately £150 to £280 per month, with similar dose-dependent pricing. Saxenda (liraglutide), a daily injection alternative, typically costs £200 to £290 per month. These prices usually include the prescription fee and medication but may not include delivery costs, which vary by provider. Most private providers offer flexible payment options and may provide discounts for upfront payment of multiple months' supply. Individual prescriber fees may also apply, typically ranging from £30 to £100 for the initial consultation and ongoing reviews.
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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 Weight Loss Injection Access and Availability
Through the NHS, weight loss injections are prescribed free of charge once you have been assessed and approved by a specialist tier 3 or tier 4 weight management service. However, access varies significantly by region—some areas have well-established services while others have lengthy waiting lists of six months to two years. Your GP can refer you to your local service, but not all GPs actively refer patients for injectable weight management treatment. NICE guidance approves tirzepatide (Mounjaro) and semaglutide (Wegovy) for eligible adults, but regional commissioning decisions affect actual availability. If you don't wish to wait for NHS assessment, private prescribing offers faster access without requiring a GP referral, though at personal cost.
- 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.
Are weight loss injections free on the NHS?
Yes, once prescribed through an NHS specialist weight management service, weight loss injections like Mounjaro and Wegovy are free. However, access varies greatly by region, and waiting lists can be several months to two years long. Your GP can refer you, but you'll need to meet specific BMI and health criteria first.
What's the difference in cost between NHS and private weight loss injections?
NHS prescriptions are free but involve waiting times and regional availability issues. Private prescriptions cost £130–£320 monthly depending on medication and dose, but offer faster access without NHS referral. Private treatment requires an online clinical assessment and ongoing prescriber fees (typically £30–£100 per consultation).
Can I switch from private to NHS weight loss injections?
In theory, yes—you can apply for NHS referral while privately prescribed. However, the process varies by region and some services may not accept patients already on private treatment. It's best to contact your local tier 3 weight management service directly to ask about their policy on mid-treatment transfers.
Which weight loss injection is cheapest in the UK?
Saxenda (liraglutide) is often the most competitively priced, starting around £150–£190 monthly, though prices vary by provider. Mounjaro and Wegovy range from £150–£320 depending on dose. It's worth comparing prices across different private providers, as they vary. The best choice depends on clinical suitability, not cost alone.
What else should I budget for when getting weight loss injections privately?
Beyond monthly medication costs, budget for initial prescriber consultation (£30–£100), ongoing review appointments (£30–£100 quarterly), and potential delivery charges. You may also want to work with a nutritionist or dietitian (£50–£150 per session), though this isn't mandatory. Some providers offer package deals combining medication and consultations.
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.