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
Can Mounjaro Cause Dizziness?
Yes, dizziness can occur with Mounjaro (tirzepatide), though it is listed as a common side effect rather than very common. Dizziness may happen during dose titration or when your body adjusts to the medication. In the UK, understanding potential side effects is essential when considering prescription weight loss treatment through your GP or a private online prescriber. Most episodes of dizziness are mild and tend to improve as your body adapts to the KwikPen injection.
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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.
How Common Is Dizziness with Mounjaro?
According to the UK product information and clinical trial data, dizziness occurs in approximately 1 in 20 to 1 in 50 Mounjaro users — classified as a common side effect. This is different from very common side effects like nausea or diarrhoea, which affect more than 1 in 10 people. Dizziness with Mounjaro may be related to several factors: rapid blood sugar changes, dehydration, blood pressure fluctuations, or adjustment to reduced calorie intake alongside the medication. It is most likely during the initial weeks of treatment or when dose titration occurs (typically every 4 weeks as you progress from 2.5 mg up to 15 mg). Most users find that dizziness resolves within the first few weeks as your body adapts. If dizziness persists or is severe, contact your GP or prescriber immediately — there may be a medical reason requiring assessment.
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.
Accessing Mounjaro in the UK: NHS vs Private Cost
In the UK, you can access Mounjaro through two main routes. NHS access: Through tier 3 specialist weight management services — typically requires a GP referral and assessment of eligibility (BMI 30+ or 27+ with weight-related conditions). NHS waiting lists vary significantly by region; many areas have long delays. Private prescription route: Available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. Private Mounjaro costs typically range from £120 to £250+ per month depending on dose. Before starting any prescription weight loss treatment, whether NHS or private, a prescriber will assess whether tirzepatide is suitable for you, review potential side effects including dizziness, and discuss management strategies.
- 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 with Mounjaro dangerous?
Mild dizziness is usually not dangerous and typically resolves within a few weeks. However, if you experience severe dizziness, fainting, chest pain, or shortness of breath, seek medical attention immediately. Always report persistent dizziness to your GP or prescriber.
What should I do if I feel dizzy after a Mounjaro injection?
Sit or lie down until the dizziness passes. Stay hydrated — dehydration can worsen dizziness. Eat regular small meals to maintain stable blood sugar. Avoid driving or operating machinery until it resolves. Contact your prescriber if dizziness is severe or lasts more than a few hours.
Does dizziness happen with other weight loss injections like Wegovy?
Yes, dizziness is also a common side effect of Wegovy (semaglutide), affecting a similar proportion of users. Compare your individual risk with our GLP-1 weight loss calculator, which helps you understand potential side effects at different doses alongside other aspects of treatment.
Can I prevent dizziness when taking Mounjaro?
Stay well hydrated throughout the day, eat balanced regular meals, avoid rapid position changes (sit up slowly), and limit alcohol. Some users find dizziness worse on an empty stomach. Work with your prescriber to discuss preventive strategies if you experience dizziness.
How much does private Mounjaro cost in the UK per month?
Private Mounjaro costs vary by dose and provider, typically ranging from £120 to £250+ monthly. Starter doses (2.5 mg) are usually cheaper; higher doses (10–15 mg) cost more. Prices vary between GPhC-registered online pharmacies — always compare options and ensure you're using a legitimate, regulated service.
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.