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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Can Mounjaro Cause Dizziness?
Yes, dizziness is a known side effect of Mounjaro (tirzepatide), though it affects relatively few people. According to UK prescribing information, dizziness is listed as a common side effect — meaning it may affect up to 1 in 10 people taking the medication. This guide explains why dizziness occurs, how to manage it, and when to contact your GP for advice. If you're considering Mounjaro or already taking it through an NHS tier 3 weight management service or private prescription, understanding this side effect can help you know what to expect.
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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.
Why Does Mounjaro Cause Dizziness?
Dizziness with Mounjaro can happen for several reasons. gradual weight management itself can cause temporary dizziness as your body adjusts — losing weight changes blood pressure and blood volume. Nausea and vomiting, which are very common Mounjaro side effects, can also trigger dizziness by dehydrating you or affecting your inner ear balance. Additionally, dose titration (when your dose increases from 2.5 mg up to the maximum 15 mg per week) can temporarily worsen side effects, including dizziness, as your body adapts to higher levels of the medication.
Mounjaro slows gastric emptying, meaning food stays in your stomach longer. This can affect nutrient absorption and blood sugar levels, both of which may contribute to dizziness. Low blood sugar (hypoglycaemia) is particularly relevant if you're also taking diabetes medication — your prescriber may need to adjust other medications as Mounjaro improves blood sugar control.
Most people find dizziness improves after the first few weeks as their body adapts, or the sensation may ease when moving between dose increments.
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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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Managing Dizziness and When to Contact Your GP
If you experience dizziness while taking Mounjaro, try staying well hydrated, eating regular small meals, rising slowly from sitting or lying down, and avoiding sudden movements. Keep a symptom diary — note when dizziness occurs, how long it lasts, and what you're doing at the time. This information helps your GP assess whether it's medication-related or something else.
Contact your GP immediately if:
- Dizziness is severe or persistent (lasting more than a few days)
- You're also experiencing chest pain, shortness of breath, or fainting
- Dizziness doesn't improve after the first few weeks on Mounjaro
- It worsens with each dose increase
Your prescriber may suggest staying on your current dose longer before increasing, or may recommend a slower titration schedule. You can also try our free GLP-1 weight loss calculator to track how your symptoms correlate with projected weight loss — sometimes understanding the context helps.
- 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 dizziness a common side effect of Mounjaro in the UK?
Yes, dizziness is listed as a common side effect, affecting up to 1 in 10 people taking Mounjaro. However, most people do not experience it, and when they do, it typically improves within the first few weeks as the body adapts to the medication.
Can dizziness be caused by gradual weight management rather than the medication itself?
Absolutely. gradual weight management can cause dizziness because it changes blood volume, blood pressure, and electrolyte balance. This is especially true in the first 4–8 weeks when weight loss is often most rapid. Staying hydrated and eating regular meals helps manage this type of dizziness.
Should I stop taking Mounjaro if I feel dizzy?
No — do not stop taking Mounjaro without consulting your GP or prescriber. If dizziness is mild and improving, continue as advised. If it's severe or worsening, contact your GP, who can assess whether dose adjustment, a longer titration period, or investigation of other causes is needed.
What's the difference between dizziness caused by Mounjaro versus low blood sugar?
Mounjaro-related dizziness is usually steady and linked to dose changes or nausea. Low blood sugar dizziness comes on suddenly, often with shakiness, sweating, and hunger. If you're also taking diabetes medication, low blood sugar is more likely — tell your prescriber immediately.
How long does dizziness from Mounjaro typically last?
Most people find dizziness resolves within 1–3 weeks as the body adapts. If it persists beyond 4 weeks or worsens with dose increases, speak to your GP — it may indicate a need for slower titration or investigation of other factors affecting your balance.
Ready to take control of your weight loss journey?
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