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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Mounjaro 10mg — UK Weight Loss Injection Dose Guide
Mounjaro 10mg is a prescription-only weight loss injection dose available in the UK for adults with excess weight. It contains tirzepatide, a dual GLP-1 and GIP receptor agonist that may help reduce appetite and support feeling fuller after meals. The 10mg dose is typically reached during dose titration after starting at 2.5mg and gradually increasing over weeks. Clinical trials showed adults on 10mg experienced an average weight loss of approximately 19.5% of body weight, though individual results vary significantly. Always consult your GP or healthcare professional before considering this medication.
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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 10mg Works & Dose Schedule
Mounjaro 10mg is administered as a once-weekly injection using a KwikPen device. It is a dual receptor agonist, meaning it activates both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 hormone pathways simultaneously — this dual mechanism differs from other weight loss injections like Wegovy, which target GLP-1 alone.
- Starting dose: 2.5mg (weeks 1–4)
- Escalation: 5mg (weeks 5–8), then 7.5mg (weeks 9–12)
- 10mg dose: typically reached around weeks 13–16
- Maximum dose: 15mg (higher doses available if needed)
Each dose is held for a minimum of 4 weeks before increasing. The 10mg dose represents a mid-to-high therapeutic level. Clinical trial data showed approximately 19.5% average body weight loss on this dose over 72 weeks, alongside a reduced-calorie diet and increased physical activity. Our GLP-1 weight loss calculator can help you project potential outcomes at the 10mg dose based on your starting weight.
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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.
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Mounjaro 10mg Eligibility & Side Effects to Know
In the UK, Mounjaro 10mg is typically prescribed for adults with a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Lower BMI thresholds (BMI 27.5+) may apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage due to higher health risks at these weights.
Common side effects at 10mg include nausea, diarrhoea, constipation, and stomach discomfort — these often decrease with time. Serious but rare side effects include pancreatitis (severe stomach pain) and gallbladder problems. Your prescriber will assess your individual suitability and manage dose progression. You can track your weight loss progress using our free progress tracker and use our BMI calculator to monitor your BMI category changes throughout treatment.
- 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.
How long does it take to reach the 10mg Mounjaro dose?
The dose titration schedule takes approximately 13–16 weeks to reach 10mg. Starting at 2.5mg, you increase to 5mg after 4 weeks, then 7.5mg after 4 more weeks, then 10mg after another 4 weeks. Each dose must be held for at least 4 weeks. Your prescriber may adjust this timeline based on how you tolerate each dose.
What's the difference between Mounjaro 10mg and Wegovy?
Mounjaro (tirzepatide) has a dual GIP + GLP-1 mechanism, while Wegovy (semaglutide) is GLP-1 only. Mounjaro maximum dose is 15mg weekly; Wegovy maximum is 2.4mg weekly. In clinical trials, Mounjaro at 10mg showed approximately 19.5% average weight loss, compared to Wegovy's ~15% average. Both require prescription and clinical assessment.
Is Mounjaro 10mg available on the NHS in the UK?
Mounjaro is available through NHS specialist tier 3/4 weight management services following NICE approval. However, NHS access is limited by regional availability and waiting lists can be lengthy. Private prescribing is available through UK-licensed prescribers following an online clinical assessment, often with faster access than NHS routes.
Are there serious side effects at the 10mg dose?
Most side effects are gastrointestinal (nausea, diarrhoea, constipation). Rare serious side effects include pancreatitis (severe upper stomach pain radiating to the back) and gallbladder complications. Seek urgent medical attention if you experience severe stomach pain, persistent vomiting, or signs of allergic reaction. Your prescriber will screen for contraindications before prescribing.
Will I lose weight on Mounjaro 10mg?
Clinical trials showed average weight loss of approximately 19.5% body weight at 10mg over 72 weeks — but individual results vary significantly. Weight loss depends on your starting weight, adherence to a reduced-calorie diet, physical activity, and individual metabolism. Some people may lose more or less than the trial average. Consistent use alongside lifestyle changes optimises outcomes.
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.