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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Cheap Alternatives to Mounjaro in the UK
If you're looking for cost-effective alternatives to Mounjaro in the UK, Wegovy (semaglutide) is the most widely available option and often more affordable privately. This guide explains how to access GLP-1 weight loss injections through NHS specialist services or private online consultations, what each route costs, and how these medications compare. Both Mounjaro and Wegovy are prescription-only medicines, so access requires a clinical assessment from a UK-licensed prescriber.
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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.
Wegovy: The Main Mounjaro Alternative & UK Pricing
Wegovy (semaglutide) is a once-weekly GLP-1 injection licensed for weight management in the UK and is frequently cited as a more affordable alternative to Mounjaro, particularly through private channels. Key differences include: Wegovy uses a single GLP-1 mechanism, while Mounjaro uses a dual GIP/GLP-1 mechanism. Wegovy starts at lower doses (0.25 mg) with a gentler titration schedule, while Mounjaro starts at 2.5 mg. In clinical trials, average weight loss with Wegovy was approximately 15% of body weight, compared to Mounjaro's 15–21% range—though individual results vary significantly.
Private Wegovy costs typically range from £129–£180 per month depending on dose and provider, making it substantially cheaper than Mounjaro, which often costs £180–£250 per month privately. Both require a prescription following an online clinical assessment. The lower price point of Wegovy has made it increasingly popular with UK patients seeking cost-effective weight loss support.
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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.
NHS vs Private: Access Routes & Real Costs
NHS access: Both Mounjaro and Wegovy are available through NHS specialist tier 3 weight management services, but only if you meet eligibility criteria and are referred by your GP. NHS availability varies widely by region—some ICBs have limited stock or long waiting lists (sometimes 1–2 years). There is no cost if prescribed through the NHS.
Private access: Online consultations with UK-licensed prescribers cost £20–£50, with medication costs ranging from £129–£250 per month depending on dose. This route is faster (often 1–2 weeks) but requires you to pay fully. Use our free GLP-1 weight loss calculator to explore potential results at different doses before committing to any route.
- 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 Wegovy cheaper than Mounjaro in the UK?
Yes, privately Wegovy typically costs £129–£180/month compared to Mounjaro at £180–£250/month. This makes Wegovy the more affordable option for most UK patients accessing weight loss injections through private online prescribing. Both require ongoing prescription costs; the NHS covers neither without specialist referral.
Can I get Mounjaro or Wegovy free on the NHS?
Both are available through NHS specialist weight management services (tier 3) if you meet clinical criteria and are referred by your GP. However, NHS availability varies by region—some areas have very long waiting lists. Your GP can advise whether you qualify and what local services are available.
How does Wegovy compare to Mounjaro for weight loss?
In clinical trials, Mounjaro achieved average weight loss of 15–21% of body weight versus Wegovy's approximately 15%. Both work alongside diet and exercise. The difference is modest—individual results vary greatly. Mounjaro's dual mechanism may suit some patients better; Wegovy's lower starting dose suits others. Your prescriber can advise which suits you.
What's the fastest way to get weight loss injections in the UK?
Private online consultations are fastest—typically 1–2 weeks from consultation to first injection. NHS referral through your GP is free but can involve 6–24 month waiting times depending on your region. Your choice depends on budget, timeline, and clinical eligibility.
Do I need to continue taking the medication for results to last?
Yes. Weight loss medications work while you take them. If you stop, weight typically returns over time unless dietary and lifestyle changes have been sustained. This is why long-term use (usually minimum 6–12 months) is recommended, and why ongoing costs matter when budgeting for treatment. ```
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.