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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Mounja — Understanding Mounjaro Weight Management
"Mounja" is commonly a misspelling of Mounjaro, a prescription-only weight management injection licensed in the UK. If you've come across this term while researching weight loss options or NHS guidance on weight management, you may be looking for information about tirzepatide — the active ingredient in Mounjaro. This guide clarifies what Mounjaro is, how it works as part of a healthy weight UK approach, and how to access it through NHS health advice or private routes. Understanding the correct medication name helps you find accurate information and make informed decisions about your health.
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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.
What Is Mounjaro (Not Mounja)?
Mounjaro is the brand name for tirzepatide, a prescription-only weight management injection available in the UK. It's manufactured by Eli Lilly and works by activating two natural hormone pathways — GIP and GLP-1 — making it a dual-action medication. This is different from other weight loss injections like Wegovy (semaglutide), which activates only GLP-1. Mounjaro may help reduce appetite, support feeling fuller after meals, and assist with sustainable weight loss alongside a reduced-calorie diet and increased physical activity. You inject it once weekly under the skin. It's important to note that Mounjaro is not insulin and works through a completely different mechanism. The medication is subject to additional MHRA monitoring (Black Triangle status), which means it's being closely watched for safety.
- Once-weekly injection (pre-filled KwikPen)
- Dual GIP + GLP-1 receptor agonist mechanism
- Doses range from 2.5 mg to 15 mg
- Requires a prescription and clinical assessment
- Available through NHS specialist services and private prescribing
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.
UK Eligibility and Access Routes
In the UK, you may be eligible for Mounjaro if you have a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, prediabetes, high blood pressure, or sleep apnoea. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply. Access is available through two main routes: NHS specialist tier 3 weight management services (usually by GP referral, with potential waiting lists) or private online prescribing via a UK-licensed prescriber following a clinical assessment. Your GP can help determine if Mounjaro is suitable for you and discuss which route is appropriate. You can also use our free BMI calculator to check your current BMI and understand where you fall on the NHS healthy weight scale.
- 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.
Is "mounja" the same as Mounjaro?
"Mounja" appears to be a misspelling of Mounjaro. Mounjaro is the correct brand name for tirzepatide, a prescription weight management injection. If you've encountered "mounja" in online searches or forums, it's likely referring to this medication. Always use the correct spelling when researching or discussing the medication with your GP or prescriber.
How does Mounjaro differ from Wegovy?
Both are prescription weight loss injections licensed in the UK, but they work differently. Mounjaro (tirzepatide) is a dual GIP + GLP-1 agonist, while Wegovy (semaglutide) activates only GLP-1. Clinical trials showed Mounjaro achieved average weight loss of approximately 15–21% of body weight, while Wegovy showed around 14.9%. Individual results vary significantly, and both require a prescription and lifestyle changes.
Can I get Mounjaro on the NHS in the UK?
Yes, Mounjaro is available on the NHS through specialist tier 3 weight management services. However, access varies significantly by region and usually requires a GP referral. Many areas have waiting lists. Private access is also available through UK-licensed prescribers following an online clinical assessment. Your GP can advise on NHS availability in your area and whether private access might be suitable.
What are the common side effects of Mounjaro?
Very common side effects include nausea, diarrhoea, vomiting, constipation, and stomach pain — these often improve over time as your body adjusts. Other common effects include indigestion, fatigue, dizziness, and injection site reactions. Serious side effects are rare but include severe stomach pain (possible pancreatitis) and gallbladder problems. Always report any concerning symptoms to your prescriber immediately.
How can I check if Mounjaro is right for me?
Start by checking your BMI using our free BMI calculator on this page — this shows your current weight category according to NHS guidelines. If you fall within eligible BMI ranges or have weight-related health conditions, discuss Mounjaro with your GP. They can assess your individual health, medical history, and whether this medication suits you. Private prescribers also conduct thorough clinical assessments before prescribing.
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.