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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How Much Will Mounjaro Increase By? UK Titration Guide
Mounjaro (tirzepatide) is prescribed in the UK using a stepwise dose escalation schedule, which means your dose increases gradually over several months. Each increase is carefully timed to give your body time to adjust, and you'll only move to the next dose if tolerated well. Understanding this titration process helps you know what to expect on your weight loss journey.
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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 Dose Escalation in the UK
Mounjaro dose increases follow a standard schedule in the UK, with each dose level lasting a minimum of 4 weeks before escalation. Your prescriber may pause or extend any dose if you're experiencing side effects, so timings can vary individually. The standard progression is: 2.5 mg (weeks 1–4), then 5 mg (weeks 5–8+), 7.5 mg (weeks 9–12+), 10 mg (weeks 13–16+), 12.5 mg (weeks 17–20+), and 15 mg (week 21+) — the maximum dose.
Each KwikPen contains 4 weekly injections, so you'll need a new pen approximately every month. The purpose of gradual titration is twofold: it allows your body to adapt to the medication and it helps identify the lowest effective dose for you. Clinical data shows that many people achieve significant weight loss at the 5 mg or 7.5 mg dose, so your prescriber may recommend stopping escalation if you're seeing good results and tolerating the medication well.
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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.
Managing Increases & NHS Prescribing
If you're accessing Mounjaro through NHS specialist weight management services (tier 3), dose escalation is managed by your specialist team at each appointment or review. Private prescribers follow the same evidence-based schedule but may manage your increases via telehealth reviews. You can use our free GLP-1 weight loss calculator to project potential outcomes at different doses based on clinical trial data, which may help you discuss realistic expectations with your prescriber.
Never increase your dose yourself — only your prescriber can authorise escalation. If you experience significant side effects (severe nausea, vomiting, or stomach pain), inform your prescriber immediately; they may extend the time at your current dose or adjust your approach rather than escalating.
- 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.
Why does Mounjaro dose increase so gradually in the UK?
Gradual titration allows your body to adapt to the medication and minimises side effects. It also helps identify the lowest effective dose for you personally. Most people tolerate each increase well, but extending each dose for 4 weeks reduces nausea and other adjustments.
What's the difference between each Mounjaro dose level?
Each increase (2.5 mg to 5 mg, then 5 mg to 7.5 mg, etc.) typically produces additional weight loss benefit. Clinical trials show 15–21% average weight loss at maximum dose, but many people achieve excellent results at lower doses. Individual response varies significantly.
Can my prescriber skip dose levels or increase faster?
Your prescriber may individualise your schedule based on tolerability and response. However, MHRA guidance recommends minimum 4 weeks at each dose. If you're tolerating well and wanting faster escalation, discuss this with your prescriber — they can advise what's safe for you.
How long does the full titration schedule take in the UK?
Following the standard schedule without pauses, reaching maximum dose (15 mg) takes approximately 20 weeks (just under 5 months). However, many people stay at lower doses long-term, so the full schedule isn't always necessary.
What if I miss a Mounjaro injection during titration?
If you miss a dose within 4 days, take it as soon as you remember and resume your normal schedule. If more than 4 days have passed, skip that dose and take your next one on the usual day. Never double-dose. Contact your prescriber if you're unsure about timing.
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.