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
Why Does Mounjaro Make You Dizzy?
Dizziness can occur as a side effect when taking Mounjaro (tirzepatide), particularly during the dose titration phase or when increasing doses. Whilst not listed as a very common side effect in UK prescribing information, dizziness has been reported by some patients. This guide explains what causes it, when it's concerning, and how to manage it safely within the NHS and UK healthcare framework. Always discuss any new or worsening symptoms with your GP or prescriber.
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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.
Understanding Dizziness on Mounjaro Treatment
Dizziness on Mounjaro can occur through several mechanisms. Dehydration is a primary cause — Mounjaro frequently causes nausea, vomiting, and diarrhoea, which increase fluid loss. Low blood sugar (hypoglycaemia) may develop if you're also taking diabetes medications like insulin or sulphonylureas, as Mounjaro enhances insulin sensitivity. Rapid gastric emptying during early treatment can affect nutrient and medication absorption, potentially lowering blood pressure temporarily. Blood pressure changes can occur as weight loss progresses. Additionally, the dose titration phase — where you increase from 2.5 mg to higher doses over weeks — may trigger dizziness as your body adjusts to the medication.
- Dehydration from gastrointestinal side effects
- Interactions with diabetes medications causing low blood sugar
- Changes in blood pressure during weight loss
- Dose escalation and body adjustment
- Nutrient absorption changes affecting electrolytes
Your prescriber can help identify which factor applies to you and adjust your treatment plan accordingly.
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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 Seek NHS Medical Help for Dizziness
Contact your GP or NHS 111 immediately if dizziness is accompanied by: chest pain, severe shortness of breath, fainting, confusion, vision changes, or signs of a heart attack. These require urgent evaluation. Book a routine GP appointment if dizziness persists beyond a few days, worsens despite hydration, or interferes with daily activities. Your GP can check your blood pressure, blood sugar, and electrolyte levels. If taking diabetes medications alongside Mounjaro, dose adjustments may be needed. Always inform your prescriber of any new symptoms when your dose increases — this is expected practice during the titration phase, and they can advise whether continuing, pausing, or adjusting your dose is 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.
Can I prevent dizziness while taking Mounjaro?
Yes — stay well hydrated (aim for 2–3 litres of water daily), eat regular small meals to stabilise blood sugar, avoid standing up too quickly, and ensure adequate electrolytes. If taking insulin or diabetes medications, your GP may need to reduce the dose as Mounjaro improves insulin sensitivity. Report any dizziness to your prescriber during dose increases.
Is dizziness a sign I should stop Mounjaro?
Not necessarily. Mild, temporary dizziness during dose titration is common and often resolves within days. However, persistent or severe dizziness requires GP assessment. Your prescriber may recommend pausing the next dose, staying on your current dose longer, or adjusting other medications. Never stop Mounjaro abruptly without medical guidance.
How does dizziness on Mounjaro differ from other side effects?
Dizziness is less commonly reported than nausea, diarrhoea, or constipation, but it's still a recognised effect. It typically suggests dehydration, low blood sugar, or blood pressure changes rather than a direct medication reaction. Addressing the underlying cause — hydration, food intake, or medication interactions — usually resolves it.
What should I tell my GP about dizziness on Mounjaro?
Report when dizziness started (during a dose increase?), how long it lasts, whether you feel faint or unsteady, other symptoms (nausea, sweating, blurred vision), and any diabetes medications you're taking. Your GP may check blood pressure sitting and standing, blood sugar levels, and electrolytes to identify the cause.
Can Mounjaro dose adjustment help with dizziness?
Yes, in many cases. Staying on your current dose longer before escalating, or pausing your next increase until dizziness resolves, allows your body to adjust. Your prescriber can also review interactions with other medications. This is part of personalised titration — there's no single timeline that suits everyone.
Ready to take control of your weight loss journey?
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