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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Weight Loss Injections Prices in the UK
Weight loss injections are prescription medications available in the UK for adults who meet specific eligibility criteria. If you're considering GLP-1 weight loss medication, understanding the costs and options — both through the NHS and private providers — is essential. This guide covers the main prescription weight management options available, how pricing works, and how to find out whether you qualify. Use our free BMI calculator above to check if you might be eligible for prescription weight loss treatment.
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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.
UK-Licensed Weight Loss Injections and Costs
Three prescription-only medications are currently licensed for weight management in the UK:
- Mounjaro (tirzepatide) — once-weekly injection, typically £129–£320 per month depending on dose (2.5mg to 15mg). Dual GIP and GLP-1 agonist.
- Wegovy (semaglutide) — once-weekly injection, typically £149–£299 per month (0.25mg to 2.4mg). Single GLP-1 agonist.
- Saxenda (liraglutide) — daily injection, typically £89–£199 per month (0.6mg to 3mg). Single GLP-1 agonist.
Prices vary between GPhC-registered online pharmacies. All three are available on the NHS through specialist tier 3 weight management services, though access is limited and waiting lists vary significantly by region. Private prescriptions typically cost £20–£50 per consultation, with medication costs on top. Our GLP-1 weight loss calculator can help you compare potential outcomes at different doses.
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 and Finding Out If You're Eligible
On the NHS, weight loss injections are available through specialist weight management services after GP referral. You must have a BMI of 30 or above, or 27–29.9 with a weight-related health condition (type 2 diabetes, hypertension, cardiovascular disease, or sleep apnoea). Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may be eligible at lower BMI thresholds. However, NHS availability is limited and waiting times are often lengthy.
Privately, you can access these medications via registered online pharmacies without an NHS referral. A UK-licensed prescriber conducts a clinical assessment, and if appropriate, issues a prescription. This is faster than NHS routes but costs significantly more. Your first step is always to discuss weight management options with your GP, who can assess your eligibility and discuss both NHS and private pathways.
- 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 is the cheapest weight loss injection available on the NHS?
On the NHS, all three medications (Mounjaro, Wegovy, and Saxenda) are available free if you meet eligibility criteria and are accepted by a tier 3 weight management service. Costs depend on your local ICB, not the medication type. Private costs vary: Saxenda is often the most affordable at around £89–£199/month, while Mounjaro and Wegovy typically range £129–£320/month.
How much do weight loss injections cost privately in the UK?
Private prices vary by provider and dose. Consultation fees are typically £20–£50. Mounjaro costs roughly £129–£320/month, Wegovy £149–£299/month, and Saxenda £89–£199/month. Prices are higher at maintenance doses. Compare GPhC-registered online pharmacies for current pricing.
Am I eligible for weight loss injections on the NHS?
You may be eligible if your BMI is 30 or above, or 27–29.9 with a weight-related health condition (diabetes, hypertension, cardiovascular disease, sleep apnoea). South Asian, Chinese, Black African, and Black Caribbean adults may qualify at BMI 27.5 or above. Ask your GP for referral to a tier 3 weight management service.
How long does it take to get weight loss injections on the NHS?
Waiting times vary significantly by region and local NHS availability. Some areas have waiting lists of several months to over a year. Private routes are typically faster — clinical assessment and first prescription can be completed within days. Speak to your GP about both options and local waiting times.
Which weight loss injection is most effective for weight management?
Clinical trials show Mounjaro (tirzepatide) achieved approximately 20.9% average body weight loss at the highest dose, compared to Wegovy (semaglutide) at around 14.9%. However, individual results vary significantly. All three medications work best alongside reduced-calorie diet and increased physical activity. Your GP or prescriber can advise which suits your circumstances.
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.