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
Does Mounjaro Cause Vertigo?
Vertigo and dizziness are not listed as common side effects of Mounjaro (tirzepatide) in UK clinical data, but some people do report feeling dizzy or unsteady after starting this weight management injection. If you experience vertigo whilst taking Mounjaro, it's important to understand whether it's related to the medication itself or other factors like gradual weight management, dehydration, or underlying health conditions. This guide explains what the evidence shows and when to contact your GP.
10,000+ calculations today · NHS-aligned thresholds · 100% free
Calculate Your BMI Instantly
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.
Understanding Dizziness With Mounjaro
Dizziness is listed as a common side effect in UK clinical trials of Mounjaro, meaning it may affect up to 1 in 10 people. However, true vertigo (the sensation that the room is spinning) is rarely reported directly. The distinction matters: dizziness is often lightheadedness or unsteadiness, whilst vertigo is a specific spinning sensation. Several factors can contribute to dizziness during Mounjaro treatment:
- gradual weight management — losing weight quickly can affect blood pressure and inner ear fluid balance
- Dehydration — Mounjaro side effects like nausea and diarrhoea increase fluid loss
- Blood pressure changes — weight loss may lower blood pressure, causing lightheadedness
- Inner ear sensitivity — gastrointestinal changes may indirectly affect balance mechanisms
- Dose escalation — dizziness may occur when increasing your tirzepatide dose
If dizziness began before starting Mounjaro or worsens significantly, an underlying condition unrelated to the medication may be responsible.
Clinically BackedWeight Loss
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.
When to Contact Your GP
Contact your GP or healthcare provider if you experience:
- Severe vertigo that prevents you from standing or walking safely
- Dizziness accompanied by chest pain, shortness of breath, or confusion
- Persistent dizziness lasting more than a few days after dose increases
- Vertigo with vision changes or hearing loss
- Symptoms that worsen despite staying hydrated and resting
In the meantime, stay well hydrated, move slowly when standing, and avoid driving or operating machinery if dizzy. Your GP may adjust your Mounjaro dose, suggest you pause weight loss temporarily, or investigate other causes. Always inform your prescriber of all symptoms — they can assess whether this tirzepatide side effect is temporary or requires dose adjustment.
- 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 vertigo a listed side effect of Mounjaro in the UK?
Dizziness is listed as a common side effect of Mounjaro (tirzepatide), but true vertigo (spinning sensation) is not specifically highlighted. Dizziness occurs in clinical trials but is usually mild and temporary. Report persistent vertigo to your GP to rule out other causes.
Can gradual weight management from Mounjaro cause vertigo?
Yes. Losing weight quickly can lower blood pressure and affect inner ear fluid balance, both of which may cause dizziness or lightheadedness. This is more likely at higher Mounjaro doses. Staying hydrated and moving slowly when standing can help reduce symptoms.
What should I do if I feel dizzy when starting Mounjaro?
Ensure you're drinking enough water, as Mounjaro side effects like nausea and diarrhoea increase dehydration risk. Avoid sudden position changes, eat balanced meals, and rest if symptoms are severe. If dizziness persists beyond a few days or worsens, contact your GP or prescriber immediately.
Could my vertigo be unrelated to Mounjaro?
Yes. Vertigo can have many causes including inner ear problems, migraines, blood pressure issues, or infections — none related to tirzepatide. If your dizziness started before Mounjaro or is very severe, your GP should investigate other possibilities.
Will stopping Mounjaro supports my vertigo?
If vertigo is dose-related, your prescriber may reduce your tirzepatide dose or pause treatment temporarily to see if symptoms improve. Do not stop Mounjaro without medical guidance. Your GP will help determine the cause and best course of action.
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.