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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Mounjaro Mg in the UK — Cost, Access & Doses
Mounjaro (tirzepatide) comes in doses ranging from 2.5 mg to 15 mg, dosed once weekly as an injection. The cost and how you access it in the UK depends on whether you go through the NHS or choose private prescription. This guide explains the different doses, what they cost, and the two main routes to getting Mounjaro in the UK.
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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.
Mounjaro Doses and Private UK Costs
Mounjaro is available in six dose strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. Each KwikPen contains four weekly injections, so one pen lasts four weeks. Your prescriber starts you on 2.5 mg and gradually increases the dose every four weeks (this is called dose titration) until you reach an effective dose, up to a maximum of 15 mg per week.
Private prescription costs for Mounjaro in the UK typically range from £129 to £320 per month, depending on your dose and the online prescribing service you use. Higher doses cost more. Prices vary between GPhC-registered pharmacies, so comparing providers is worth doing. Some services offer bundle packages if you commit to multiple months. Private access is available without an NHS referral — you complete an online clinical assessment with a UK-licensed prescriber who will assess whether tirzepatide is suitable for you.
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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
NHS access to Mounjaro is through specialist tier 3/4 weight management services, not your GP directly. You need to be referred by your GP and assessed by a multidisciplinary team. NICE has approved tirzepatide for use within NHS weight management services, but availability varies significantly by region and waiting lists can be very long — sometimes months or years. You must meet NHS eligibility criteria (BMI ≥30 or ≥27 with weight-related health conditions) and be willing to engage with lifestyle support.
Private access is faster. You complete an online consultation with a UK-licensed prescriber, who reviews your health and eligibility. If approved, a prescription is issued to a GPhC-registered pharmacy. This typically takes 1–7 days. Private prescriptions require you to meet clinical eligibility but avoid NHS waiting lists. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different Mounjaro doses alongside lifestyle changes.
The online consultation process for private prescription typically involves a health questionnaire covering your weight, height, medical history, current medications, and any contraindications (pregnancy, gallbladder disease, pancreatitis history, or thyroid cancer). The prescriber reviews this and may request additional information — for example, recent blood pressure readings or details about previous weight loss attempts. If you're eligible, a prescription is generated and sent to a pharmacy. Medication arrives at your home within days. You inject once weekly on the same day each week. Always inform your prescriber of all medications you're taking, as Mounjaro can affect oral contraceptive absorption and may interact with diabetes medications. Our BMI calculator can help you assess your current weight status and baseline before starting treatment.
- 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's the difference between Mounjaro and other UK weight loss injections like Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials show Mounjaro may produce slightly higher average weight loss (around 20.9% body weight at 15 mg vs around 15% for Wegovy). Both are once-weekly injections. Access and pricing in the UK are similar — available via NHS specialist services or private prescription. Individual results vary significantly.
Can I get Mounjaro on the NHS in the UK?
Yes, NICE has approved tirzepatide (Mounjaro) for use within NHS specialist weight management services. However, access requires GP referral to a tier 3/4 service and assessment by a multidisciplinary team. Availability and waiting times vary dramatically by region — some areas have long waiting lists. NHS eligibility requires BMI ≥30 or ≥27 with weight-related health conditions. Private prescription is typically faster if you meet clinical criteria.
What happens if I increase my Mounjaro dose — does the cost go up?
Yes. Private prescription costs increase with higher doses. A 2.5 mg or 5 mg dose typically costs less than 15 mg. One pen (four weeks of injections) at a higher dose costs more than the same pen at a lower dose. Costs vary between pharmacies. When your prescriber increases your dose every four weeks during titration, your monthly cost will gradually increase as you reach your target dose.
How long does it take to get Mounjaro through private prescription in the UK?
Private prescription is typically faster than NHS. You complete an online consultation, a UK-licensed prescriber reviews your health within 24–48 hours, and if approved, a prescription is sent to a pharmacy. Medication usually arrives within 3–7 days. NHS access through specialist services can take several months or longer depending on regional waiting lists and service capacity.
Do I need to take Mounjaro forever, or is it a short-term treatment?
Mounjaro is typically used as a longer-term weight management tool. Clinical trials show that when people stop using GLP-1 or GIP/GLP-1 medications, weight regain can occur. Most prescribers recommend continuing treatment as long as it's helping and you're tolerating it well. Your prescriber will review your progress regularly and discuss whether to continue, adjust dose, or stop based on your individual response and health goals.
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.