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
Does Mounjaro Cause Depression? What the Evidence Shows
Depression is not listed as a common side effect of Mounjaro in clinical trials, but some people have reported mood changes while taking tirzepatide. This guide explains what the evidence shows, how Mounjaro works in your body, and what to do if you experience mood symptoms. It's important to discuss any mental health concerns with your GP, as they can assess whether changes are related to the medication or other factors. Always contact your healthcare provider if you have concerns about how Mounjaro is affecting your wellbeing.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 the Clinical Trials Showed About Mounjaro and Mood
The SURMOUNT clinical trials that led to Mounjaro's UK approval did not identify depression as a common side effect of tirzepatide. The most frequently reported side effects were gastrointestinal — nausea, diarrhoea, vomiting, and constipation — which typically improve as your body adjusts to the dose.
However, clinical trials capture only formally reported adverse events during specific timeframes. Real-world experience may differ. Some people have reported mood changes, including low mood or depressive symptoms, though these reports are not common. It's unclear whether these changes are directly caused by Mounjaro, related to gradual weight management itself, underlying health conditions, or other medications the person is taking.
If you experience persistent sadness, hopelessness, or loss of interest in activities while taking Mounjaro, contact your GP immediately. Your GP can assess whether the symptoms are related to the medication and help you decide on next steps — which may include continuing, adjusting the dose, or switching to a different medication.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
How Mounjaro Works and Why Mood Changes Might Occur
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that works on hormone pathways controlling appetite, blood sugar, and food enjoyment. It slows stomach emptying and signals fullness to your brain. These mechanisms are not directly related to mood regulation.
However, several indirect factors during weight loss treatment could affect mood: gradual weight management can impact energy levels; nutritional deficiencies from restricted eating may affect mental health; the stress of lifestyle changes; or improved health outcomes actually lifting mood. Mounjaro is also used for type 2 diabetes management, and blood sugar regulation can influence mood. Use our free GLP-1 weight loss calculator to see projected weight loss, then track your physical and mental wellbeing alongside progress with our progress tracker.
If you have a history of depression, anxiety, or other mental health conditions, inform your prescriber before starting Mounjaro. They can monitor you more closely and assess whether this is the right medication for you. Some people benefit from weight loss medication while managing mental health effectively; others may need a different approach. Your prescriber and GP can work together to ensure you're supported on all fronts.
Report mood changes promptly: Don't wait for your next scheduled injection. Contact your GP or prescriber if you notice persistent low mood, thoughts of self-harm, increased anxiety, or significant emotional changes. These conversations are routine and important for safe medication use.
- 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 depression a known side effect of Mounjaro listed by the MHRA?
Depression is not listed as a common side effect in the official product information or SURMOUNT clinical trials. The most common side effects are gastrointestinal (nausea, diarrhoea, constipation). However, mood changes have been reported by some users in real-world experience, though causation is unclear and may relate to weight loss itself, other medications, or underlying health factors rather than tirzepatide directly.
What should I do if I feel depressed while taking Mounjaro?
Contact your GP or prescriber immediately. They can assess whether your mood changes are related to Mounjaro, explore other contributing factors, and discuss your options — which may include continuing the medication, adjusting the dose, adding mental health support, or switching to an alternative. Don't stop taking Mounjaro without medical guidance.
Can weight loss itself affect mental health while taking Mounjaro?
Yes. gradual weight management can impact energy, mood, and self-image. Nutritional deficiencies, dehydration, or insufficient calorie intake alongside Mounjaro can lower mood. Additionally, some people experience improved mood from positive health outcomes, while others feel anxious about lifestyle changes. This variation is normal and individual.
Who should avoid Mounjaro if they have depression?
Anyone with active depression, suicidal thoughts, or severe mental health conditions should discuss this with their GP and prescriber before starting Mounjaro. They can assess the risks and benefits for your specific situation. Mounjaro is not contraindicated in depression, but close monitoring is important.
How is Mounjaro different from Wegovy regarding mood side effects?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) work on GLP-1 pathways and have similar side effect profiles — neither lists depression as common. Mounjaro is a dual GIP/GLP-1 agonist, which some research suggests may have additional metabolic benefits, but mood effects are comparable between the two. Individual experiences vary.
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.