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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What Are The Doses Of Mounjaro In The UK?
Mounjaro (tirzepatide) is available in six different dose strengths in the UK, ranging from 2.5 mg to 15 mg, administered as a once-weekly injection via KwikPen. Your prescriber will start you on the lowest dose and gradually increase it over several weeks, a process called dose titration. This approach helps your body adjust to the medication whilst minimising side effects. Understanding how Mounjaro dosing works is important whether you're accessing it through NHS tier 3 specialist weight management services or via private prescribing routes 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 Dose Schedule And Titration Protocol
Mounjaro doses follow a structured escalation plan. You begin with 2.5 mg weekly for weeks 1–4, then progress to 5 mg for weeks 5–8+. If tolerated well, your prescriber may increase to 7.5 mg (weeks 9–12), then 10 mg (weeks 13–16), 12.5 mg (weeks 17–20), and finally 15 mg (week 21 onwards) as the maximum therapeutic dose.
Each dose must be maintained for a minimum of 4 weeks before escalation. Your prescriber will not rush this process — they assess your tolerability, side effects, and weight loss response at each stage. Each KwikPen contains 4 doses (4 weeks' supply), so you'll need a new prescription approximately every month. If you experience troublesome side effects, your prescriber may pause escalation or keep you on a stable dose rather than continuing upward titration.
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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 Access To Mounjaro And Dose Management
In the UK, Mounjaro is accessed through NHS tier 3 specialist weight management services via GP referral, or privately through registered prescribers. NHS services follow NICE guidance and assess eligibility based on BMI (30+ or 27+ with weight-related health conditions). Once prescribed, your NHS specialist team will monitor your progress at regular intervals, adjusting your dose based on clinical response and tolerability.
Regional variation in NHS availability means waiting times differ significantly across the UK — some areas have established Mounjaro services whilst others have limited access. Privately, prescribers follow similar dose protocols but may offer more flexible appointment scheduling. Whichever route you access Mounjaro through, dose titration follows the same evidence-based schedule designed to maximise safety and effectiveness.
- 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 in the UK?
The starting dose is 2.5 mg once weekly, administered via injection. This introductory dose is maintained for 4 weeks to allow your body to adjust. Most people experience nausea or digestive side effects at this stage, which typically improve as your body adapts.
Can I stay on a lower dose of Mounjaro if a higher dose causes side effects?
Yes. Your prescriber can keep you on any dose that works well for you. Many people achieve good weight loss results on 5 mg, 7.5 mg, or 10 mg rather than the maximum 15 mg dose. Your prescriber will discuss this with you based on your individual response.
How long does it take to reach the maximum dose of Mounjaro?
Reaching 15 mg typically takes 20 weeks or more, as each dose must be held for at least 4 weeks before increasing. This gradual approach helps your body tolerate the medication. Some people never reach 15 mg if lower doses work effectively for them.
Is Mounjaro dose the same whether I access it on the NHS or privately in the UK?
Yes, the dose schedule is the same. Whether prescribed through NHS tier 3 services or private prescribers, Mounjaro follows the same titration protocol. The difference is in access pathway and monitoring arrangements, not in the medication dosing itself.
What happens if I miss a Mounjaro injection?
If you miss a dose within 4 days, take it as soon as you remember and resume your normal schedule the following week. If more than 4 days have passed, skip that dose and take your next scheduled dose. Never take a double dose to make up for a missed injection. ```
Ready to take control of your weight loss journey?
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