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
Why Is Mounjaro Going Up In Price in the UK?
Mounjaro (tirzepatide) prices have increased significantly across the UK in recent months, leaving many people wondering why costs are rising. Several factors contribute to these price increases, including supply constraints, manufacturing costs, and market demand. Understanding what's driving these changes—and knowing your NHS and private access options—can help you make informed decisions about weight management 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.
What's Causing Mounjaro Price Increases in the UK?
Mounjaro price rises are driven by several interconnected factors. Supply chain pressures have affected global pharmaceutical manufacturing, particularly for injectable medications requiring specialised storage and delivery systems like the KwikPen device. Increased demand for tirzepatide since NICE approval has outpaced supply in many regions, allowing providers to adjust pricing upward. Manufacturing complexity means producing a dual GIP and GLP-1 receptor agonist is more costly than single-mechanism alternatives like Wegovy (semaglutide). Currency fluctuations, particularly the pound's value against the US dollar, also affect UK import costs for Eli Lilly's product. Additionally, private market competition between online prescription services has stabilised somewhat after initial price wars, resulting in more consistent but higher pricing across providers. NHS access remains unaffected by these private market increases, though NHS availability varies significantly by region through specialist tier 3 weight management services.
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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 vs Private Access: How Costs Compare
NHS route: Mounjaro is available free through NHS specialist weight management services for eligible adults—no direct cost to you. However, NHS access requires referral from your GP to a tier 3 or 4 specialist service, and availability varies greatly by integrated care board (ICB). Waiting lists can be lengthy in some areas. Private route: Private online prescribing typically costs £129–£320 per month depending on your dose, with no NHS referral needed. You'll complete an online consultation with a UK-licensed prescriber who assesses your eligibility before issuing a prescription dispensed by a GPhC-registered pharmacy. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses, and consult our BMI calculator to understand your current weight category alongside any treatment decision.
- 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.
Will Mounjaro prices keep rising?
Likely to stabilise rather than continue rising steeply. Once supply catches up with demand and manufacturing scales up, prices should moderate. Private providers may offer competitive pricing as competition increases. NHS costs remain unaffected by market pressures.
Is Mounjaro cheaper than Wegovy in the UK?
Pricing is often similar between tirzepatide and semaglutide on the private market (£129–£320/month depending on dose). Wegovy typically costs slightly less at maximum dose because semaglutide is more established. Both are available free on the NHS for eligible patients through specialist services.
Why is NHS Mounjaro free when private costs so much?
NHS medications are purchased at negotiated bulk prices far lower than private retail prices. The NHS pays manufacturers significantly less per dose than private patients through pharmacies, allowing free provision to eligible patients within NHS services.
Can I get Mounjaro on the NHS if I'm waiting too long?
Yes. You can pursue private prescription while on an NHS waiting list—the two pathways are separate. Some people do both. Discuss with your GP if you're considering private treatment alongside NHS referral, as they may need to note this in your medical records.
What does the KwikPen cost separately?
The KwikPen device is included in the prescription cost—you don't pay for it separately. Each pre-filled KwikPen contains four weekly doses (one month's supply). Disposal is free at pharmacies. The device cost is built into the per-dose pricing you pay.
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.