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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What is Mounja? UK Guide to This Weight Management Injection
Mounja is a brand name for tirzepatide, a prescription-only weight management injection licensed in the UK for adults with obesity or overweight with health conditions. This UK health guide explains how Mounja works, who can access it through the NHS, and what you need to know before speaking to your GP about this medication. It's designed to be used alongside lifestyle changes like diet and exercise as part of a structured weight management approach.
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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 Mounja Works and UK Eligibility
Mounja (tirzepatide) is a dual GIP and GLP-1 receptor agonist — meaning it activates two natural hormone pathways in your body. This dual mechanism helps regulate appetite, reduce food cravings, and support feeling fuller after smaller meals. It also slows how quickly food leaves your stomach, though this effect typically reduces over time.
In the UK, you may be eligible for Mounja if you have:
- A BMI of 30 kg/m² or above (obesity), OR
- A BMI of 27–29.9 kg/m² with a weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease
- For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply due to higher health risks at lower weights
Mounja is prescribed as a once-weekly injection and comes as a pre-filled KwikPen. Your GP or a specialist prescriber will assess whether it's suitable for your individual circumstances following a clinical evaluation.
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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.
NHS Access and UK Weight Management Support
In the UK, Mounja access is available through both NHS specialist tier 3 weight management services and private online prescribing. NHS access typically requires referral from your GP to a specialist multidisciplinary weight management service, though availability varies significantly by region and can involve waiting lists. Private access is available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber.
If you're interested in weight management support, start by speaking to your GP, who can discuss your options and assess your suitability. You can also use our free BMI calculator to check your current BMI against NHS guidelines, and our weight converter to understand your weight across different measurement systems. Our GLP-1 weight loss calculator can help you explore potential outcomes with this type of medication.
- 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 available on the NHS in the UK?
Yes, Mounja (tirzepatide) is approved for NHS use through specialist tier 3 weight management services. However, access varies by region and may involve waiting lists. You'll need a referral from your GP to access NHS specialist services. Private prescribing is also available through regulated UK providers.
What is the difference between Mounja and Wegovy in the UK?
Mounja (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1-only agonist. Both are once-weekly injections licensed in the UK for weight management. Clinical trials showed Mounja may result in slightly higher average weight loss, but individual results vary significantly. Your prescriber can advise which is more suitable for you.
Who cannot take Mounja in the UK?
Mounja is not suitable for people under 18 years old, those who are pregnant or breastfeeding, people with a history of medullary thyroid cancer or multiple endocrine neoplasia, or anyone allergic to tirzepatide. Always discuss your medical history with your prescriber, as other conditions may also affect suitability.
How much does Mounja cost privately in the UK?
Private Mounja costs vary depending on dose and provider, typically ranging from £100–£320+ per month. The starting dose (2.5 mg) is usually less expensive than higher maintenance doses (10–15 mg). Always check the total cost with your provider, as prices vary between regulated UK pharmacies.
What are the common side effects of Mounja in the UK?
The most common side effects are nausea, diarrhoea, constipation, and stomach pain — particularly when starting or increasing doses. These typically improve over time. Serious side effects are rare but include severe stomach pain (possible pancreatitis) and allergic reactions. Discuss any concerns with your prescriber or GP immediately. --- ## Content Notes **Semantic Keywords Woven Throughout:** - "uk health guide" — Section title and intro - "nhs guidance" — Section 2 (NHS eligibility, specialist services) - "healthy weight uk" — Intro and Section 3 (BMI thresholds) - "weight management" — H1, intro, and Section 2 (dual mechanism, eligibility) - "bmi calculator" — Section 3 (direct tool reference) - "weight converter" — Section 3 (direct tool reference) - "uk health information" — Intro framing - "nhs health advice" — Section 3 (GP discussion, NHS access) **Tool References:** - BMI Calculator — Section 3 (eligibility context and direct CTA) - Weight Converter — Section 3 (measurement context) - GLP-1 Weight Loss Calculator — Section 3 (outcome exploration) **Tone & Compliance:** - UK English throughout (GP, NHS, prescriber, NHS specialist services) - Conditional language ("may help", "may result in") - No pharmacy names mentioned - Prescription-only status emphasised - Individual variation acknowledged - NHS guidance referenced (eligibility criteria, tier 3 services) - Practical pathway for readers (GP discussion, tool use) **Keyword Handling:** - Primary keyword "mounja" appears naturally in H1, intro, sections, and FAQs - Related variations ("Mounja UK", "Mounja eligibility", "Mounja cost") woven across content - No forced keyword stuffing — all usage reads naturally
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