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
Mounjaro and Dementia Risk — What the Evidence Shows
There is no established link between Mounjaro (tirzepatide) and dementia risk in current UK health guidance or clinical trial data. Recent media coverage has raised questions about GLP-1 medications and cognitive health, but regulatory bodies including the MHRA have found no causal evidence. This guide explains what we know, what research shows, and when to speak with your GP about weight management options including Mounjaro.
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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.
What Does Current Research Show About Mounjaro and Dementia?
Clinical trials for Mounjaro (the SURMOUNT studies) did not identify dementia or cognitive decline as a safety concern. The MHRA, which regulates all medicines in the UK, continues to monitor tirzepatide closely and has not issued any warnings linking the medication to dementia risk. Some observational studies have suggested a possible association between GLP-1 receptor agonists and reduced dementia risk in people with type 2 diabetes—potentially because better blood sugar control supports brain health. However, these findings are preliminary and require further investigation. The key point is that no regulatory authority has identified a causal link between Mounjaro and dementia. If you have concerns about cognitive health or family history of dementia, discuss these with your GP before starting any weight management medication. Your prescriber can assess your individual risk factors and help you make an informed decision.
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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.
NHS Guidance and When to Speak to Your GP
The NHS recommends that weight management decisions—including prescription medications like Mounjaro—should be made in partnership with your GP or a specialist weight management service. If you have a family history of dementia, neurological conditions, or existing cognitive concerns, mention this during your clinical assessment. Your GP can review your full medical history and any medications you take. Mounjaro is prescribed through NHS tier 3 specialist weight management services or via private online prescribing after clinical assessment. Either route involves a conversation with a licensed healthcare professional who will consider your individual health profile. Never start or stop any medication without professional guidance.
- 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 there scientific evidence that Mounjaro causes dementia?
No. Clinical trials for Mounjaro did not show a link to dementia or cognitive decline. The MHRA continues to monitor tirzepatide and has issued no safety warnings about dementia risk. Some research suggests GLP-1 medications may support brain health through improved blood sugar control, but more evidence is needed. Always discuss concerns with your GP.
What should I tell my GP if I have family history of dementia?
Mention family history of dementia, Alzheimer's disease, or other neurological conditions during your clinical assessment. Your GP or prescriber needs your full medical history to assess whether Mounjaro is appropriate for you. This information helps them weigh benefits against any individual risk factors you may have.
Can I use MyWeightCheck's BMI calculator to check my eligibility for Mounjaro?
Yes—use our free BMI calculator to calculate your current BMI instantly. Mounjaro may be suitable if your BMI is 30 or above, or 27+ with weight-related health conditions. However, BMI is just one factor. A GP or licensed prescriber must assess your full health profile before prescribing.
What is the difference between Mounjaro and Wegovy regarding dementia risk?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are GLP-1-type medications. Neither has been linked to dementia in clinical trials or UK regulatory guidance. Both require a prescription and clinical assessment. Your prescriber can explain the differences and help you choose what's right for you.
How do I get a prescription for Mounjaro through the NHS in the UK?
NHS access to Mounjaro is through specialist tier 3 weight management services. Your GP can refer you if you meet eligibility criteria (BMI 30+, or 27+ with weight-related health conditions). Waiting times vary by region. Private online prescribing is also available—use the GLP-1 calculator on this page to estimate potential outcomes with treatment.
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.