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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Blurry Vision and Mounjaro — What You Need to Know
Blurry vision is a reported side effect of tirzepatide (Mounjaro), though it is not one of the most common effects. This guide explains what blurry vision means in the context of Mounjaro use, how to access this medication in the UK through both NHS and private routes, and what you can expect in terms of costs and clinical assessment. If you experience vision changes while taking Mounjaro, always contact your GP or prescriber immediately for 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.
Understanding Blurry Vision as a Mounjaro Side Effect
Blurry vision is listed as an uncommon side effect of tirzepatide (Mounjaro) in UK prescribing information. It is not reported in clinical trials as a very common effect, but some users have reported temporary vision changes during dose escalation or in the early weeks of treatment.
Why might this happen? Potential mechanisms include rapid blood sugar changes (especially in those with type 2 diabetes), dehydration, or individual sensitivity to the medication. Vision changes can also occur if Mounjaro affects fluid balance or blood pressure.
What should you do? If you notice blurry vision while taking a GLP-1 medication like Mounjaro, contact your GP or prescriber immediately. Do not drive if your vision is significantly affected. Vision changes may resolve within days or weeks as your body adjusts, but medical assessment is essential to rule out other causes such as diabetic retinopathy complications.
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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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Accessing Mounjaro in the UK — NHS vs Private Cost Routes
NHS route: Mounjaro is available through NHS specialist tier 3/4 weight management services following NICE approval. Access is via GP referral and can involve substantial waiting lists (months to over a year in many areas). If prescribed through the NHS, there is no direct cost to you beyond normal prescription charges (£9.90 per item in England for most adults).
Private route: UK-licensed online prescribing services offer consultations and Mounjaro prescriptions without NHS referral. Costs typically range from £160–£280 per month depending on your dose and the prescribing provider. The Mounjaro KwikPen device costs vary: a single pen (4 weeks' supply) ranges from approximately £40–£70 per dose level. Private prescribing is faster—often within 1–2 weeks—and requires an online clinical assessment with a UK-licensed prescriber.
Before starting Mounjaro through any route, your prescriber will assess your eligibility based on BMI (typically 30 or above, or 27+ with weight-related health conditions like type 2 diabetes), medical history, and current medications. Use our free BMI calculator to check where you stand against NHS guidelines. Your prescriber will also review any vision problems or eye conditions before prescribing. Dose titration begins at 2.5 mg and increases gradually over weeks, so costs escalate as you progress to higher maintenance doses. Always discuss blurry vision and any other side effects with your prescriber—they may adjust your dose, monitor your blood sugar control, or refer you for eye examination if needed.
- 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 blurry vision a common side effect of Mounjaro?
Blurry vision is listed as an uncommon side effect of tirzepatide. It is not reported in clinical trials as a very common effect, though some users report temporary vision changes during dose escalation. Always contact your GP if you experience vision changes—they can assess whether it is related to Mounjaro or another cause.
How much does Mounjaro cost on the NHS in the UK?
If prescribed through the NHS, Mounjaro costs the standard prescription charge (£9.90 per item in England). However, accessing Mounjaro via the NHS typically requires referral to a specialist weight management service, which can involve waiting lists of several months to over a year depending on your region.
What is the typical cost of private Mounjaro prescriptions in the UK?
Private Mounjaro usually costs £160–£280 per month depending on your dose level. A single KwikPen (4 weeks' supply) ranges from approximately £40–£70 per injection, with costs increasing as you escalate from the starting 2.5 mg dose to higher maintenance doses.
How do I access Mounjaro through a private UK prescription?
Private online prescribing services offer consultations with UK-licensed prescribers. You complete a health questionnaire, have a video or telephone consultation, and if approved, receive a prescription to be dispensed by a GPhC-registered pharmacy. The process typically takes 1–2 weeks and does not require NHS referral.
What should I do if I experience blurry vision while taking Mounjaro?
Contact your GP or prescriber immediately. Do not drive if vision is significantly affected. Vision changes may resolve as your body adjusts, but medical assessment is essential to rule out serious causes like diabetic retinopathy complications or other underlying conditions.
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