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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When To Increase Your Mounjaro Dose For Weight Loss
Mounjaro (tirzepatide) requires a careful dose escalation schedule supervised by your prescriber. This guide explains the NHS-aligned approach to dose increases, what to expect at each stage, and how your weight loss response is monitored. Your prescriber will assess your tolerance and results before any increase — there is no fixed timeline that applies to everyone, as individual responses vary significantly.
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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.
How Mounjaro Dose Titration Works In The UK
Mounjaro is supplied as a weekly weight loss injection delivered via the KwikPen device, with doses escalating over several weeks. Your prescriber follows a structured titration schedule: you start at 2.5 mg for 4 weeks, then progress to 5 mg, 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg (the maximum dose). You must remain on each dose for at least 4 weeks before any increase — this allows your body to adjust and your prescriber to assess how well you're tolerating the medication and losing weight.
The key principle is that dose increases are not automatic. Your prescriber will only escalate if: (1) you're tolerating the current dose without intolerable side effects, (2) you're experiencing meaningful weight loss, and (3) there are no safety concerns. If you experience severe nausea, vomiting, or other serious side effects, your dose may not increase — or you may need to pause before continuing. Use our GLP-1 weight loss calculator to project potential outcomes at different dose levels based on clinical trial data.
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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.
When Your Prescriber May Delay or Skip a Dose Increase
Not every patient increases through all dose levels. Your prescriber may recommend staying on your current dose if you're already achieving good weight loss results, have reached your goal, or if you're experiencing bothersome side effects that improve at the current dose level. Some patients find that 5 mg or 10 mg is their optimal dose — increasing further may not improve results and could increase side effects. Additionally, if you have other medical conditions or take certain medications (particularly oral contraceptives), your prescriber may recommend a slower escalation or a lower maximum dose. Track your progress using our free progress tracker to identify patterns in your weight loss and side effect tolerance — this information helps your prescriber make informed decisions about dose adjustments.
- 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 happens if I don't lose weight on my current Mounjaro dose?
If you're not seeing meaningful weight loss after 4 weeks on a dose, your prescriber may recommend increasing to the next dose level. However, they'll also assess whether lifestyle factors (diet, activity) need adjustment. Weight loss medication works best alongside a reduced-calorie diet and increased physical activity — medication alone is not sufficient.
Can I increase my Mounjaro dose faster than 4 weeks?
No. UK prescribing guidance requires a minimum of 4 weeks on each dose before escalation. Faster increases raise safety risks and prevent your body from adjusting properly. Your prescriber will not recommend faster titration outside of this schedule.
How much weight should I lose at each Mounjaro dose level?
Individual results vary significantly. Clinical trials showed average weight loss of approximately 15–21% body weight at maximum dose, but this varies by person, dose level, and adherence to lifestyle changes. Our GLP-1 weight loss calculator shows average trial data — your personal results may differ.
What if I want to stay on a lower Mounjaro dose?
You can absolutely remain on a lower dose (5 mg, 10 mg, etc.) if you're satisfied with your weight loss, achieving your goals, or experiencing manageable side effects. Dose increases are not mandatory — the goal is finding the optimal dose for your health, not reaching the maximum dose.
Is Mounjaro dose titration different on the NHS versus private prescription?
The titration schedule is the same — all UK prescribers follow MHRA guidance requiring 4-week intervals minimum between dose increases. NHS specialist services and private prescribers both use this same protocol. Access varies by region (NHS) or provider (private), but the clinical approach is consistent.
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.