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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Cheapest Weight Loss Injection in the UK
If you're looking for the cheapest weight loss injection in the UK, it's important to understand that costs vary significantly depending on whether you access prescription weight loss medication through the NHS or privately. Wegovy (semaglutide), Mounjaro (tirzepatide), and Saxenda (liraglutide) are all licensed for weight management in the UK, but pricing differs considerably by dose, provider, and route. This guide breaks down the actual costs and helps you understand what affects the price of weight loss injections in the UK.
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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.
Understanding UK Weight Loss Injection Pricing
Weight loss injections in the UK fall into two pricing categories: NHS access and private prescription. On the NHS, weight loss medication is available through specialist tier 3 weight management services, but availability is extremely limited and varies significantly by region. When NHS access is available, there is no charge at the point of care beyond your standard prescription charge (currently £11.90 per prescription in England, regardless of dose). However, waiting lists for NHS specialist services can span months or even years in many areas, and not all regions commission these services equally.
Privately, weight loss injections are available through GPhC-registered online prescribing services. Current typical costs range from approximately £129 to £320 per month depending on the medication, dose, and provider. Wegovy generally costs between £180–£280 per month for the maximum dose. Mounjaro typically ranges from £200–£320 per month at higher doses. Saxenda (daily injection) costs roughly £130–£150 per month. Costs are lower at starting doses and increase as you escalate through the treatment pathway.
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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.
Which Injection Is Cheapest — and What Affects Price?
The "cheapest" option depends on your circumstances. At the lowest starting doses, Saxenda is often the lowest-cost option, as it is typically priced around £130 per month even at the starting dose. However, it requires daily injections rather than once-weekly, which may affect adherence. Wegovy and Mounjaro are both once-weekly injections and more convenient, though typically slightly more expensive at equivalent doses. Many private providers offer tiered pricing or discounts for larger upfront commitments (for example, paying for three months in advance). To check costs accurately, you'll need to request quotes from different GPhC-registered online prescribing services, as pricing varies between providers. Remember that all weight loss injections are prescription-only medicines and require a clinical assessment before being prescribed. Cost should never be the only factor — your GP or prescriber will assess which medication is clinically appropriate for you based on your health profile, BMI, and any existing conditions.
- 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.
Is Mounjaro or Wegovy cheaper in the UK?
Wegovy typically costs £180–£280/month at maximum dose, while Mounjaro ranges £200–£320/month. Costs vary by provider and dose. Saxenda is often cheapest at around £130–£150/month, but requires daily injections instead of weekly. Always request quotes from multiple providers.
Can I get weight loss injections free on the NHS?
Yes, through NHS specialist weight management services (tier 3). However, availability is extremely limited and varies by region. Waiting lists can be very long. Your GP can refer you, but access depends on your BMI, health conditions, and local NHS commissioning. Private access is faster but involves costs.
What's the difference between Wegovy and Ozempic pricing?
Wegovy (semaglutide 2.4mg) is licensed for weight loss in the UK. Ozempic (semaglutide up to 2mg) is licensed for type 2 diabetes, not weight loss. Using Ozempic for weight loss is off-label. Wegovy is the appropriate licensed option and is priced for weight management use (£180–£280/month typically).
Does dose affect the price of weight loss injections?
Yes, significantly. Starting doses (e.g., Wegovy 0.25mg or Mounjaro 2.5mg) cost less than maximum doses (Wegovy 2.4mg or Mounjaro 15mg). You escalate doses gradually over weeks, so initial costs are lower. Full-dose pricing typically applies after 3–4 months of treatment escalation.
Can I use MyWeightCheck tools to estimate my eligibility for weight loss injections?
Yes. Use our free BMI calculator to check your current BMI — adults with BMI 30+ (or 27+ with weight-related health conditions) may be eligible for weight loss medication. Our GLP-1 weight loss calculator can also help you explore projected weight loss at different doses and understand the clinical trial data behind these medications.
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.