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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Why Is Mounjaro Going Up in the UK?
Mounjaro (tirzepatide) prices have been rising across the UK since its launch for weight management. The cost increases reflect several factors including supply constraints, manufacturing costs, and rising demand. Whether you're considering Mounjaro through the NHS or private prescription, understanding pricing trends and access routes will help you make an informed decision about weight management options available to you.
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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.
Understanding Mounjaro Pricing in the UK
Private prescription costs for Mounjaro have increased significantly. When Mounjaro was first available for private prescription in the UK, costs ranged from approximately £150–£200 per month for starting doses. Current private prescription costs now typically range from £180–£320+ per month, depending on your dose and the prescribing provider. The KwikPen device contains 4 weeks of doses, so monthly costs scale with dose escalation — higher doses (10mg, 15mg) cost more than lower starting doses (2.5mg, 5mg).
Several factors drive these increases:
- Supply and demand: Mounjaro demand has exceeded supply globally, giving manufacturers greater pricing power
- Manufacturing complexity: Tirzepatide production is more complex than simpler GLP-1 medications, increasing per-unit costs
- Regulatory compliance: Mounjaro carries additional MHRA monitoring (Black Triangle ▼ status), increasing oversight and compliance costs
- Currency fluctuations: UK prescription prices are affected by sterling value against the US dollar
- Distribution and logistics: Cold-chain storage and importation of injectable medications adds cost
Unlike many oral medications, injectable weight management drugs cannot be substituted for cheaper generics — you receive the brand-name KwikPen device as manufactured.
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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: What's Available Now?
NHS access to Mounjaro remains limited and variable by region. NICE has approved tirzepatide for use within specialist NHS weight management services, but access depends on your ICB (Integrated Care Board) and local tier 3 or tier 4 services availability. Many NHS regions have extensive waiting lists — sometimes 12–24 months — due to overwhelming demand and limited budgets. Your GP cannot prescribe Mounjaro directly; you must be referred to a specialist weight management service.
Private prescription remains the fastest access route. After an online consultation with a UK-licensed prescriber, if Mounjaro is clinically appropriate for you, a prescription is issued to a GPhC-registered pharmacy. The entire process typically takes 1–3 working days. Use our free GLP-1 weight loss calculator to understand potential outcomes and whether medication might support your goals alongside lifestyle changes.
NHS access to Mounjaro remains limited and variable by region. NICE has approved tirzepatide for use within specialist NHS weight management services, but access depends on your ICB (Integrated Care Board) and local tier 3 or tier 4 services availability. Many NHS regions have extensive waiting lists — sometimes 12–24 months — due to overwhelming demand and limited budgets. Your GP cannot prescribe Mounjaro directly; you must be referred to a specialist weight management service.
Private prescription remains the fastest access route. After an online consultation with a UK-licensed prescriber, if Mounjaro is clinically appropriate for you, a prescription is issued to a GPhC-registered pharmacy. The entire process typically takes 1–3 working days. Use our free GLP-1 weight loss calculator to understand potential outcomes and whether medication might support your goals alongside lifestyle changes.
- 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 dose of Mounjaro should I expect to pay for?
Costs vary by dose. Starting doses (2.5mg, 5mg) are cheapest — typically £180–£220/month privately. Maximum dose (15mg) costs £280–£320+/month. Your prescriber will start you on 2.5mg and increase gradually, so early costs are lower. NHS prescriptions are free once initiated through a specialist service.
Why has Mounjaro become so expensive compared to when it launched?
Global demand far exceeds supply, giving manufacturers pricing power. Manufacturing tirzepatide is complex, and MHRA monitoring adds regulatory costs. Currency fluctuations and distribution logistics also contribute. Similar patterns occurred when Wegovy (semaglutide) first launched — prices typically stabilise once supply increases and patents expire.
Is Mounjaro cheaper than Wegovy in the UK?
Pricing is comparable at equivalent doses, though individual provider costs vary. Mounjaro typically ranges £180–£320/month; Wegovy usually £150–£280/month. Direct price comparison depends on your dose level and prescribing provider. Our free BMI calculator can help determine if you're eligible for either medication.
How can I reduce the cost of Mounjaro treatment?
Start on the lowest dose (2.5mg) — costs are lower initially. Explore NHS referral if waiting lists are acceptable in your region — NHS prescriptions are free. Compare private providers, as costs vary. Confirm your BMI is ≥30 or ≥27 with comorbidities — you must meet eligibility to be prescribed safely.
Will Mounjaro prices come down in the future?
Eventually, yes — likely within 5–10 years when patents expire and generic versions become available. Similar happened with other injectable medications. For now, supply constraints and patent protection keep costs elevated. NHS budgets may also expand, improving access without out-of-pocket cost.
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.