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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Dizziness on Mounjaro — Common Causes and Management
Dizziness can occur when taking Mounjaro (tirzepatide), though it is not listed as a very common side effect in clinical data. Dizziness may be related to several factors including rapid blood sugar changes, dehydration, nausea, or how quickly your body adjusts to the medication. Most cases are mild and temporary, but if you experience persistent or severe dizziness, you should contact your GP or prescriber immediately. This guide explains what causes dizziness on Mounjaro and when to seek medical advice.
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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 Dizziness Occurs on Mounjaro
Dizziness on Mounjaro can develop for several interconnected reasons. Blood sugar regulation: Mounjaro works by improving how your body manages blood sugar, which can cause sudden drops (hypoglycaemia) particularly if you are also taking diabetes medication. Rapid blood sugar changes trigger dizziness and lightheadedness. Dehydration: Mounjaro commonly causes nausea, vomiting, and diarrhoea — all of which increase fluid loss. Dehydration is a frequent cause of dizziness. Appetite suppression and calorie deficit: As Mounjaro reduces appetite through its dual GIP and GLP-1 receptor agonist mechanism, some people consume significantly fewer calories than usual. A sharp calorie drop can cause fatigue and dizziness, especially in the first few weeks. Dose adjustment: Dizziness may occur during dose titration (escalation) as your body adapts to increased medication levels. Medication interactions: If you take blood pressure medication or other drugs that affect cardiovascular function, Mounjaro may interact, lowering blood pressure and causing dizziness.
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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.
When to Contact Your GP or Prescriber
Mild, occasional dizziness that resolves quickly may be manageable with home care, but contact your GP or prescriber immediately if:
- Dizziness is persistent, severe, or worsening
- You faint or lose consciousness
- Dizziness is accompanied by chest pain, shortness of breath, or rapid heartbeat
- You develop severe headache alongside dizziness
- Dizziness prevents you from carrying out daily activities
- You suspect your blood sugar is dangerously low (trembling, sweating, confusion, anxiety)
Your prescriber can review your dose, check your blood pressure, assess for medication interactions, and ensure Mounjaro remains appropriate for you. They may adjust your tirzepatide dose or recommend additional support.
- 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?
Dizziness is not listed as a very common side effect in clinical trials, but some people do experience it. It is more likely during the first few weeks or when your dose increases. If dizziness persists beyond the initial adjustment period, speak to your prescriber.
What can I do to manage dizziness at home?
Stay well hydrated by drinking water regularly. Eat small, balanced meals even if your appetite is suppressed — skipping meals worsens dizziness. Avoid sudden position changes; stand up slowly. Rest when needed. If nausea accompanies dizziness, ginger tea or small snacks may help. Always inform your GP of persistent symptoms.
Does dizziness mean Mounjaro is not right for me?
Not necessarily. Many people experience mild dizziness during the first few weeks as their body adjusts. However, if dizziness is severe or doesn't improve, your prescriber may adjust your dose, switch you to an alternative GLP-1 medication like Wegovy (semaglutide), or explore other options. This decision requires individual assessment.
Can dizziness on Mounjaro be related to blood sugar dropping too low?
Yes, if you take diabetes medication alongside Mounjaro, your risk of hypoglycaemia (low blood sugar) increases. This can cause dizziness, trembling, sweating, and confusion. Monitor your blood sugar if prescribed, and alert your GP if you suspect low blood sugar episodes. Dose adjustment of diabetes medication may be needed.
How long does dizziness usually last when starting Mounjaro?
For many people, mild dizziness resolves within 1–2 weeks as your body adjusts. However, if dizziness persists beyond 4 weeks, changes in severity, or worsens, contact your prescriber. Use our BMI calculator and GLP-1 weight loss calculator to track your overall health journey while managing side effects with professional support.
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.