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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Mounjaro and Dementia — What the Evidence Shows
There is no established causal link between Mounjaro and dementia based on current evidence. However, concerns have been raised about GLP-1 medications and potential neurological effects, particularly regarding weight loss speed and nutritional intake. This guide explains what we know about Mounjaro safety, dementia risk factors, and why speaking with your GP is essential before starting any prescription weight loss medication in the UK.
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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.
What Does the Evidence Say About Mounjaro and Dementia?
Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist, has not been directly linked to dementia in clinical trials or post-market safety data. The SURMOUNT trials, which evaluated tirzepatide for weight management, did not identify dementia or cognitive decline as a safety concern. The MHRA, which monitors medicines in the UK, has not issued warnings about dementia risk with Mounjaro.
However, some healthcare professionals have raised theoretical concerns about gradual weight management and potential nutritional deficiencies, which could theoretically affect brain health over the long term. These concerns are not specific to Mounjaro but apply to any gradual weight management method. Weight loss of 15–20% of body weight—achieved in clinical trials—can sometimes lead to nutritional gaps if dietary intake is not carefully managed.
- Clinical trial safety data: No dementia cases reported in SURMOUNT-1 or SURMOUNT-2
- Post-market surveillance: MHRA monitoring has not identified dementia as a safety signal
- Theoretical risk: gradual weight management without proper nutrition support could theoretically affect brain health, but this is not unique to GLP-1 medications
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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.
Dementia Risk Factors and Weight Management in the UK
Dementia risk is influenced by multiple factors: age, genetics, cardiovascular health, blood sugar control, physical activity, cognitive engagement, and diet quality. Obesity itself is associated with increased dementia risk—particularly type 2 diabetes and high blood pressure, both weight-related conditions. This means that achieving a healthy weight through safe, medically supervised methods may actually help reduce dementia risk overall.
If you're considering Mounjaro or any weight loss medication, your GP can assess your individual dementia risk profile and help ensure that weight loss is achieved in a way that supports, rather than compromises, long-term brain health. Use our free BMI calculator above to check your current weight status, then discuss the results with your GP as part of a holistic health conversation.
Before starting Mounjaro, always have a comprehensive discussion with your GP about your full medical history, including any family history of dementia or neurological conditions. Your prescriber will assess whether Mounjaro is suitable for you and may recommend additional nutritional support or monitoring if you have specific health concerns. Weight loss should always be paired with balanced nutrition, regular physical activity, and ongoing medical oversight—not rapid restriction.
- 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.
Does Mounjaro cause dementia?
No. Clinical trials did not identify dementia as a side effect, and the MHRA has not issued safety warnings linking Mounjaro to dementia. However, any gradual weight management without proper nutrition support could theoretically affect long-term health, so medical supervision is important.
Is GLP-1 medication safe for people with dementia risk?
GLP-1 medications like Mounjaro have not been shown to increase dementia risk. In fact, achieving a healthy weight may reduce risk by improving blood sugar control and cardiovascular health. Your GP can assess your individual risk profile before prescribing.
What should I tell my GP about dementia risk before starting Mounjaro?
Mention any family history of dementia, neurological conditions, or cognitive changes. Discuss your current diet quality, physical activity level, and any concerns about nutritional intake during weight loss. Your GP may recommend additional monitoring or nutritional support.
Can gradual weight management from Mounjaro affect brain health?
gradual weight management can sometimes lead to nutritional deficiencies if not managed carefully. This applies to any weight loss method, not just Mounjaro. Your GP or a dietitian can help ensure you maintain adequate nutrition while losing weight safely.
How does obesity relate to dementia risk?
Obesity increases dementia risk through several pathways: type 2 diabetes, high blood pressure, cardiovascular disease, and inflammation. Achieving a healthy weight through safe, medically supervised methods may actually help reduce dementia risk overall.
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.