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
Can You Go Down A Dose On Mounjaro?
Yes, you can go down a dose on Mounjaro, but dose reductions are typically managed by your prescriber rather than self-adjusted. Mounjaro (tirzepatide) is a prescription-only injection that requires clinical oversight. If you're experiencing side effects, wanting to pause treatment, or need to adjust your dose, this should always be discussed with the healthcare professional who prescribed it. Your prescriber can assess whether a dose reduction is appropriate for your individual circumstances.
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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 Adjustments Work
Mounjaro uses a dose titration schedule, where doses are increased gradually over weeks rather than started at the maximum. The standard progression begins at 2.5 mg weekly, then increases by 2.5 mg increments every 4 weeks up to 15 mg — the maximum dose. However, dose adjustments aren't one-directional.
If you're experiencing significant side effects, your prescriber may recommend staying at your current dose longer, reducing to a previous dose, or pausing treatment temporarily. This is different from stopping entirely — it allows your body to adapt while maintaining the benefits. Some patients find their optimal dose is lower than the maximum, and that's a valid clinical decision made between you and your healthcare provider. Always discuss any concerns about side effects, nausea, or other symptoms with the person managing your Mounjaro prescription.
Clinically BackedWeight Loss
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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 You Might Consider A Dose Reduction
Common reasons to discuss a dose reduction with your prescriber include persistent nausea or vomiting, severe gastrointestinal side effects, loss of appetite affecting nutrition, or feeling that side effects outweigh the weight loss benefits. Some patients also request reductions if they've reached their target weight and want to maintain it at a lower dose.
It's important to note that reducing your dose may mean slower weight loss or smaller total weight loss compared to staying at a higher dose — clinical trials show average weight loss varies significantly by dose level. Your prescriber will help you weigh the benefits and drawbacks. Never reduce your Mounjaro dose without medical guidance. If you're struggling with side effects, speak to your GP or the prescriber who issued your prescription. They can advise on timing, alternative approaches, or whether a temporary break might be helpful.
- 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.
Will reducing my Mounjaro dose stop my weight loss?
Not necessarily — weight loss may continue at a lower dose, though possibly more slowly than at higher doses. Clinical trials show results vary by individual and dose. Your prescriber can advise what to expect at a reduced dose based on your specific situation.
Can I reduce my Mounjaro dose myself?
No — Mounjaro is prescription-only and must be managed by your prescriber. Self-adjusting dosing risks treatment ineffectiveness or unexpected side effects. Always discuss dose changes with your GP or the healthcare professional who prescribed it.
How long does it take to feel better after lowering my dose?
Side effects like nausea often improve within days to a week after dose reduction or pausing. However, appetite and fullness sensations may also change, affecting your weight loss progress. Your prescriber will monitor how you respond.
Is going down a Mounjaro dose the same as stopping it?
No — a dose reduction means lowering to a previous dose (e.g., from 10 mg to 7.5 mg) and continuing treatment. Stopping means discontinuing completely. Both options should be discussed with your prescriber based on your health goals.
What's the difference between Mounjaro and Wegovy for dose adjustments?
Both are prescription-only and adjusted by your prescriber, but they're different tirzepatide and semaglutide medications. Mounjaro starts at 2.5 mg and goes up to 15 mg weekly. Wegovy starts at 0.25 mg and reaches 2.4 mg weekly. Your prescriber chooses based on what's appropriate for you.
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.