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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Reducing Mounjaro Dose Safely
If you're taking Mounjaro (tirzepatide) and considering reducing your dose, you need guidance from your prescriber — dose adjustments should never be made independently. This guide explains when dose reductions might be appropriate, how the adjustment process works in UK practice, and what side effects or health changes might prompt a discussion with your GP or specialist. Mounjaro is a prescription-only weight management injection, and your prescriber will assess whether a lower dose is right for you based on your individual health and tolerance.
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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.
When Mounjaro Dose Reduction Might Be Considered
Dose reduction is typically considered for specific health reasons rather than as a routine step. Your prescriber may suggest reducing your tirzepatide dose if you experience severe side effects (such as persistent nausea, vomiting, or stomach pain) that significantly impact your daily life, even after waiting several weeks for adaptation. If you develop gallbladder problems, pancreatitis symptoms, or signs of diabetic retinopathy complications, your dose may need to be lowered or stopped entirely. Some patients also request dose reduction if they've achieved their weight loss goal and want to maintain results on a lower dose, though evidence on long-term maintenance at reduced doses remains limited. Importantly, missing doses or stopping Mounjaro suddenly is not the same as a planned reduction — accidental gaps should be reported to your prescriber. Always discuss any concerns about your current dose before making changes, as your prescriber can weigh the benefits against risks.
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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.
How Dose Adjustment Works in UK Practice
Mounjaro dose adjustments are managed through your NHS specialist weight management service or private prescriber. Unlike some medications, there is no standard "reduction protocol" — adjustments are individualised based on your response, side effects, and health goals. If you're experiencing intolerable side effects, contact your prescriber to discuss timing: you may pause treatment for 1–2 weeks to let your system settle, or move to a lower dose and stay there longer before any future increase. If you're on a higher dose (10 mg, 12.5 mg, or 15 mg) and tolerating it well, reducing to maintain weight loss at a lower dose is theoretically possible but carries uncertainty about whether the lower dose will sustain your results. Your prescriber will consider your BMI, weight loss progress, and any health improvements when deciding whether reduction is advisable. Discuss your specific situation openly — this helps your prescriber make the safest, most effective recommendation for you.
- 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.
Can I reduce my Mounjaro dose on my own?
No — Mounjaro is prescription-only, and dose adjustments must always be discussed with your prescriber first. Stopping or reducing independently without medical guidance could affect your weight stability and overall health management. Contact your GP or specialist weight management service if you're considering a change.
What if I can't tolerate my current Mounjaro dose due to side effects?
Common side effects like mild nausea often improve within a few weeks as your body adapts. If effects are severe and persistent, tell your prescriber immediately. They may pause your treatment briefly, reduce to a lower dose, or explore other options. Never stop suddenly without guidance.
Will I regain weight if I reduce my Mounjaro dose?
Weight regain risk depends on the dose reduction and your individual response. Some patients maintain results at lower doses, while others experience gradual regain. Your prescriber can advise based on your progress. Continued focus on diet and physical activity supports weight stability regardless of dose.
Is there a standard protocol for reducing Mounjaro in the UK?
There's no single NHS or NICE standard — dose adjustments are personalised. Your prescriber will consider your side effects, weight loss goals, and health status when deciding on any reduction. Always discuss timing and any safety concerns before changing.
What's the difference between Mounjaro and Wegovy if I'm considering switching to a lower-dose medication?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro tends to produce greater average weight loss, but both work through similar hunger-regulation pathways. Switching requires a new prescription and clinical assessment — your prescriber can advise which is more suitable for you.
Ready to take control of your weight loss journey?
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