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 and Bloating: UK Cost and Access Guide
Bloating is one of the most commonly reported side effects when starting Mounjaro (tirzepatide) in the UK. While usually mild and temporary, understanding what causes it and how to manage it is important before accessing this prescription-only injection. This guide explains bloating in the context of UK costs and access routes — whether through the NHS or private prescription — so you can make an informed decision about treatment.
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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 Bloating Fits Into Mounjaro Cost and Access Decisions
Bloating and other gastrointestinal side effects affect how people experience Mounjaro treatment, which influences both access decisions and the overall value for money. Bloating typically occurs in the first 4–8 weeks as your stomach adjusts to the medication's effects on gastric emptying — how quickly food moves through your digestive system. While often mild, severe or persistent bloating can lead to dose reductions or treatment discontinuation, affecting the cost-benefit calculation.
Understanding bloating in advance helps you decide whether to pursue NHS specialist services (free but with longer waiting lists) or private online prescription routes (faster but at personal cost). Private prescribers can offer closer monitoring and faster dose adjustments if bloating becomes problematic. NHS specialists can provide ongoing support but may have limited appointment availability. The side effect profile, including bloating, is part of the clinical assessment both routes will conduct before issuing a prescription.
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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 Access in the UK: NHS vs Private Routes and Costs
NHS Route: Free prescriptions through tier 3 specialist weight management services. Requires GP referral. Waiting lists vary by region (ICB) — currently several months to over a year in many areas. Includes ongoing clinical monitoring and medication adjustments.
Private Route: Online consultation with a UK-licensed prescriber, typically £20–£50. If approved, Mounjaro costs roughly £130–£320 monthly depending on dose. A 2.5mg starter pen (4 doses) costs around £129, while higher doses (10–15mg) can reach £280+ monthly. Private prescribers often offer faster access and flexible appointment scheduling. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, helping you weigh costs against expected results. Check your BMI using our BMI calculator to confirm eligibility before pursuing either route.
Tirzepatide eligibility: Adults with BMI ≥30 kg/m², or BMI 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, or cardiovascular disease). South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds.
Both routes require clinical assessment confirming you have no contraindications — including severe gastroparesis or a history of medullary thyroid cancer. Bloating and other GI side effects are discussed during assessment. The KwikPen device requires no special storage equipment once opened (up to 30 days at room temperature), making private access practical. Your prescriber will guide you through dose titration schedules, starting at 2.5mg and increasing every 4 weeks if needed, which helps manage side effects like bloating.
- 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 Mounjaro bloating worse on higher doses?
Bloating often peaks during dose increases, particularly between weeks 5–12 of treatment. Higher maintenance doses (10–15mg) can trigger bloating more than starter doses (2.5–5mg). However, most people find bloating improves significantly after 8–12 weeks as their stomach adjusts. Individual experiences vary widely — some people experience minimal bloating regardless of dose.
Can I get Mounjaro on the NHS if I'm concerned about side effects like bloating?
Yes. NHS specialists conduct full clinical assessments and discuss side effects before prescribing. They monitor you throughout treatment and can adjust your dose or switch medications if bloating becomes problematic. However, NHS waiting lists are typically 6–12 months, so you won't access treatment immediately. Private prescribers offer faster access if you're willing to pay.
How much does Mounjaro cost privately in the UK, and does bloating affect the decision?
Private costs range from £129–£320 monthly depending on dose. Starting doses (2.5–5mg) are cheaper. If bloating forces you to stay on lower doses longer, your monthly cost decreases but weight loss results may be slower. Many people find the faster NHS access via private prescription worth the cost for better side effect management and dose adjustments.
What's the difference between Mounjaro and Wegovy bloating?
Wegovy (semaglutide) is a single GLP-1 agonist; Mounjaro (tirzepatide) is a dual GIP + GLP-1 agonist. Both cause bloating similarly. Clinical trials show comparable GI side effects. Mounjaro may produce slightly different outcomes, but bloating profiles are very similar. Both require prescription and clinical assessment.
Should I use the GLP-1 weight loss calculator if I'm worried about bloating affecting my results?
Yes. Our GLP-1 weight loss calculator shows potential weight loss at different doses. If bloating concerns you, you might stay on lower doses longer, which affects projected results. Seeing realistic outcomes helps you decide whether private access (for faster dose adjustments) or NHS access (for ongoing specialist support) suits your needs better. Discuss bloating management with your prescriber during clinical assessment.
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.