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 Dosage in the UK: Access, Cost & How It Works
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK through both NHS specialist services and private prescription routes. Understanding the dosage progression, how to access it, and what it costs will help you make an informed decision about whether this medication is right for you. This guide covers everything you need to know about Mounjaro dosage in the UK, from the starting 2.5 mg dose through to the maximum 15 mg, plus practical information about accessing the medication and associated costs.
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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 Dosage Progression and Cost in the UK
Mounjaro is administered as a once-weekly injectable dose using a pre-filled KwikPen device. The dose titration schedule begins at 2.5 mg and escalates gradually over 16–20 weeks, with each dose maintained for a minimum of 4 weeks before increasing:
- Weeks 1–4: 2.5 mg (starting/adjustment dose)
- Weeks 5–8: 5 mg (first maintenance dose)
- Weeks 9–12: 7.5 mg
- Weeks 13–16: 10 mg
- Weeks 17–20: 12.5 mg
- Week 21+: 15 mg (maximum dose)
Each KwikPen contains 4 weekly doses (one month's supply). Private prescription costs typically range from £129–£320 per month depending on your dose, with higher doses at the upper end of this range. NHS availability varies significantly by region, and waiting lists for specialist tier 3 weight management services can be lengthy in many areas.
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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.
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NHS vs Private Access: How to Get Mounjaro in the UK
NHS route: Referral to a specialist weight management service (tier 3 or tier 4) from your GP is the first step. However, NHS access remains inconsistent across regions, and NICE approval does not assures immediate availability in all areas. Waiting times can extend from several months to over a year.
Private route: A growing number of UK adults access Mounjaro through private online consultations with a UK-licensed prescriber. After a brief clinical assessment (medical history, current medications, contraindications), a prescription may be issued and dispensed by a GPhC-registered pharmacy. This route bypasses NHS waiting lists but requires private payment. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses to support your decision-making.
The online consultation process typically takes 24–48 hours from submission to prescription issue. You'll be asked about your weight, height, medical history, current medications (especially oral contraceptives, as Mounjaro may reduce their effectiveness), and any contraindications like pancreatitis history or family history of medullary thyroid cancer. Once approved, your prescription is sent to a pharmacy, and the first KwikPen is delivered to your home within 2–5 working days, along with full storage and injection instructions.
- 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 is the starting dose of Mounjaro, and can I skip straight to a higher dose?
The starting dose is always 2.5 mg, regardless of your weight or BMI. This allows your body to adjust and helps identify any side effects early. You cannot skip doses — each dose must be maintained for at least 4 weeks before escalating. Rapid escalation increases nausea and gastrointestinal side effects without improving efficacy.
How long does it take to reach the maximum 15 mg dose of Mounjaro?
Following the standard titration schedule, it takes approximately 20 weeks (5 months) to reach the maximum 15 mg dose. However, some people remain on lower doses like 5 mg or 10 mg if they achieve good results and tolerate the medication well — you don't need to reach 15 mg to see weight loss benefits.
Is Mounjaro available on the NHS, and how do I access it?
Yes, NICE has approved tirzepatide (Mounjaro) for NHS use within specialist tier 3 weight management services. However, availability varies by region and ICB (Integrated Care Board). Ask your GP for a referral to your local specialist weight management service. NHS waiting lists are currently very long in many areas — typical waits range from 6 months to 2+ years depending on your region.
How much does Mounjaro cost privately in the UK?
Private prescription costs typically range from £129–£320 per month depending on your dose. Starting doses (2.5–5 mg) are usually at the lower end, while maintenance doses (10–15 mg) cost more. Costs vary slightly between providers. Most private prescribers offer follow-up consultations every 4–12 weeks to monitor your progress and manage any side effects.
Do I need an ongoing prescription from my GP if I access Mounjaro privately?
No. If you access Mounjaro through a private online prescriber, you receive prescriptions directly from that prescriber — you don't need GP involvement unless you choose to inform your GP for continuity of care. However, informing your GP is recommended so they can monitor your health and manage any interactions with other medications you may be taking.
Ready to take control of your weight loss journey?
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