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 Mental Health — What the NHS Evidence Shows
Weight management with tirzepatide (Mounjaro) may affect mental health and mood, and this is an important consideration when deciding whether this prescription-only injection is right for you. The relationship between GLP-1 receptor agonist medications and mental wellbeing is complex — some people report improved mood alongside weight loss, whilst others experience changes in appetite regulation that can influence emotional eating patterns. If you're considering Mounjaro through the NHS or privately, understanding how it may affect your mental health is essential for making an informed decision about treatment.
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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 Mounjaro May Affect Mood and Mental Wellbeing
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that works primarily on appetite and blood sugar regulation. However, GLP-1 pathways are also present in brain regions that regulate mood, reward, and emotional processing. This means tirzepatide may influence mental health in several ways:
- Appetite and emotional eating: By reducing cravings and hunger signals, Mounjaro may help some people break cycles of emotional eating, potentially improving mood and self-esteem as weight decreases.
- Blood sugar stability: Better glucose control can support more stable energy and mood throughout the day.
- Weight-related psychological benefits: Successful weight loss often improves confidence, body image, and overall mental wellbeing — though this varies significantly between individuals.
- Nausea and appetite suppression: Early-stage nausea or reduced appetite may temporarily affect mood or energy, though these side effects typically diminish after the first few weeks.
Individual responses to Mounjaro vary considerably. Some people experience improved mood and mental clarity, whilst others notice no change, or in rare cases, experience mood changes that require monitoring.
Clinically BackedWeight Loss
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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 Mental Health Screening for Mounjaro
If you're accessing Mounjaro through an NHS tier 3 specialist weight management service, your prescriber will ask about your mental health history as part of the clinical assessment. This is routine and important — it helps identify whether Mounjaro is suitable for you and whether any additional monitoring is needed. Tell your GP or specialist about any history of depression, anxiety, eating disorders, or other mental health conditions, as these may affect suitability or require closer follow-up during treatment.
The MHRA (Medicines and Healthcare products Regulatory Agency) and NICE continue to monitor safety data on tirzepatide use in the UK. If you develop new or worsening mood changes, anxiety, or unusual thoughts whilst taking Mounjaro, contact your GP or prescriber immediately. Mental health changes should never be ignored — they warrant a clinical review of your treatment.
- 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 Mounjaro cause depression or anxiety?
Whilst depression or anxiety are not listed as common side effects of Mounjaro, individual responses vary. Some people experience mood changes, and GLP-1 pathways do affect mood-regulating brain regions. If you develop new mood symptoms whilst taking Mounjaro, inform your GP or prescriber immediately so they can assess whether the medication is the cause and whether continued use is appropriate.
Will Mounjaro improve my mental health?
Mounjaro itself is not an antidepressant or anti-anxiety medication. However, successful weight loss and improved blood sugar control may indirectly support mental wellbeing by boosting confidence and reducing weight-related health anxiety. That said, weight loss alone does not treat clinical depression or anxiety — if you have a diagnosed mental health condition, continue working with your mental health team alongside any weight management treatment.
Should I tell my GP about mental health conditions before starting Mounjaro?
Yes. Always disclose any history of depression, anxiety, eating disorders, bipolar disorder, or other mental health conditions when discussing Mounjaro with your GP or prescriber. This information helps them assess whether Mounjaro is safe for you and whether you need additional monitoring during treatment. Mental health history is part of a thorough clinical assessment.
Can I take Mounjaro if I'm on antidepressants?
In most cases, yes — Mounjaro can be used alongside antidepressants or other mental health medications. However, GLP-1 medications may affect how quickly some oral medications are absorbed. Inform your prescriber of all medications you're taking, including antidepressants, so they can advise on any necessary adjustments or monitoring.
How does weight loss from Mounjaro affect emotional eating patterns?
By reducing physical hunger signals and food cravings, Mounjaro may help some people step out of emotional eating cycles. However, if emotional eating is linked to an eating disorder or disordered eating patterns, it's important to work with a mental health professional alongside weight management — Mounjaro is not a treatment for eating disorders and should be avoided in active eating disorder diagnoses.
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.