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
Free tracker included with every download this week
How Much Is Mounjaro Going Up To In September?
Mounjaro (tirzepatide) uses a structured dose titration schedule, with increases typically occurring every 4 weeks if you're progressing well on your current dose. There is no single "September increase" date across the UK — your dose timing depends on when you started treatment and how your body responds. If you're receiving Mounjaro through NHS specialist services or privately, your prescriber will manage dose increases based on clinical assessment and tolerance. Understanding your personal titration schedule helps you prepare for what to expect and manage any temporary side effects during transitions.
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Calculate Your BMI Instantly
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.
How Mounjaro Dose Titration Works in the UK
Mounjaro comes in five escalating doses, and you typically progress through them at your own pace. Starting dose is 2.5 mg once weekly for at least 4 weeks. If tolerated well, your dose increases to 5 mg, then 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg — the maximum maintenance dose. Each dose is administered once weekly as an injection using a KwikPen device.
Your prescriber — whether through NHS tier 3 weight management services or a private online clinic — decides when to escalate based on: how well you're tolerating the current dose, whether you're experiencing problematic side effects (nausea, vomiting, constipation), and your weight loss progress and appetite response. Some people progress through doses quickly over 16–20 weeks; others may stay on a lower dose longer if it's working well. There is no rush to reach the maximum 15 mg dose. The goal is finding the dose that works best for your individual health and weight management, not reaching the highest number.
- 4-week minimum on each dose before escalating
- September increase depends on your start date and tolerance
- Dose timing is personalised, not calendar-based
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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 and Mounjaro Prescribing in the UK
If you're accessing Mounjaro through the NHS, you'll be managed by a specialist tier 3 weight management service following referral from your GP. NHS prescribing follows MHRA and NICE guidance, and your specialist team will manage your dose titration based on clinical assessment. NHS access varies significantly by region and ICB (Integrated Care Board) — some areas have established Mounjaro programmes, while others have waiting lists or limited availability.
Privately, you can access Mounjaro through UK-registered online clinics following an online assessment with a licensed prescriber. Private clinics typically follow the same evidence-based titration schedule but may offer more flexible appointment timing for dose reviews. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, and discuss your personal titration plan with your prescriber to understand when your next dose increase is due.
- 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.
Does everyone's Mounjaro dose go up in September?
No — dose increases are personalised and timed to every 4 weeks from your individual start date, not calendar months. Your September increase depends on when you began treatment and how well you're tolerating your current dose. Your prescriber will confirm your next increase date at each appointment.
What happens if I can't tolerate a dose increase?
If you experience severe nausea, vomiting, or other side effects preventing dose escalation, your prescriber may pause your increase or keep you on your current dose longer. Side effects often reduce after a few days. Some people find their optimal dose before reaching 15 mg, and that's clinically appropriate.
Can I request a dose increase before 4 weeks?
Dose escalation before 4 weeks is not recommended and goes against clinical guidance. The 4-week minimum allows your body to adjust and helps identify the dose that works best for you. Discuss any concerns about progress with your prescriber at your review appointment.
Is the Mounjaro titration schedule the same on NHS and private prescriptions?
Yes — both NHS and private prescribers follow the evidence-based MHRA-approved titration schedule: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg, with minimum 4 weeks between increases. The difference is NHS access pathway and regional availability, not the clinical protocol.
How do I know if I'm ready for my next Mounjaro dose increase?
Your prescriber assesses readiness based on: current side effects (generally manageable), weight loss progress, appetite response, and overall tolerance. You'll discuss this at your appointment or review consultation. If you're uncertain whether you should escalate, raise it with your GP or prescriber before your scheduled increase date.
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.