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
Free tracker included with every download this week
What Are the Side Effects of 7.5mg Mounjaro?
At the 7.5mg dose, Mounjaro (tirzepatide) may cause side effects as your body adjusts to this mid-range injection. The 7.5mg dose is typically used during the dose titration phase — usually around weeks 9–12 of treatment — as your prescriber increases your dose towards the maintenance level. Side effects at this stage are usually similar to lower doses but may persist. Most effects are temporary and tend to reduce over time. This guide explains what to expect, which side effects are common, and when to contact your GP.
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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.
Common Side Effects at 7.5mg
Very common side effects (affecting more than 1 in 10 people) during dose escalation include nausea, diarrhoea, vomiting, and constipation. Stomach (abdominal) pain is also frequently reported. These are typically most noticeable in the first few days after injection and often settle within 3–5 days as your body adjusts.
Common side effects (affecting up to 1 in 10 people) include indigestion, acid reflux (GORD), injection site reactions such as redness or bruising, fatigue, dizziness, and hair loss. Some people also report decreased appetite — which is actually the intended mechanism but can feel uncomfortable if it leads to eating too little.
At 7.5mg, you may notice these effects are slightly more pronounced than at 5mg, but most people find them manageable. Using our free GLP-1 weight loss calculator can help you understand what dose escalation stage you're at and what to expect next.
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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.
Managing Side Effects and When to Seek Help
Managing nausea and digestive issues: Eat smaller, lighter meals; avoid fatty or spicy foods; stay hydrated; take anti-sickness medication if prescribed; eat slowly and chew thoroughly.
When to contact your GP urgently: Seek immediate medical attention if you experience severe, persistent stomach pain spreading to your back (possible pancreatitis), serious allergic reactions (swelling of face, lips, throat), changes in vision, gallbladder pain, or symptoms that don't improve after one week. Most side effects at 7.5mg are mild and temporary, but your GP must assess any concerning symptoms. Always inform your prescriber if side effects are affecting your quality of life — dose adjustments or a slower titration schedule may be appropriate.
- 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 do 7.5mg Mounjaro side effects last?
Most side effects peak within 24–48 hours of injection and settle within 3–5 days as your body adjusts. By day 7 (just before your next injection), many people feel back to normal. However, some people experience mild symptoms throughout the week. If effects persist beyond one week, contact your GP — they may slow your dose escalation.
Is 7.5mg Mounjaro safe in the UK?
Yes. Mounjaro is MHRA-approved and licensed for weight management in UK adults. The 7.5mg dose is a standard part of the dose titration schedule. Your prescriber has assessed that you're eligible and suitable for this dose. However, it's prescription-only and requires ongoing clinical monitoring. Report any concerning side effects to your GP.
Can I reduce my 7.5mg dose if side effects are too much?
Do not adjust your dose yourself. If side effects are severe or affecting your quality of life, contact your prescriber or GP. They may recommend staying on your previous dose longer, slowing the titration schedule, or other management strategies. Your clinical assessment took your individual health into account, so any changes must be supervised.
Are 7.5mg side effects different from lower Mounjaro doses?
At 7.5mg, side effects are typically similar in type to 5mg but may be slightly more noticeable because your body is receiving a higher dose of tirzepatide. This is normal and expected during dose escalation. Most people tolerate the increase well. Use our GLP-1 weight loss calculator to track your dose stage and expected timeline.
What's the difference between Mounjaro and Wegovy side effects?
Both are weight loss injections but with different mechanisms. Mounjaro is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is GLP-1 only. Side effects are broadly similar (nausea, diarrhoea, constipation) because both slow stomach emptying. However, Mounjaro's dual action means some people experience slightly different patterns. Individual responses vary significantly, so ask your prescriber about your specific situation.
Ready to take control of your weight loss journey?
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