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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ADHD and Mounjaro: What the Evidence Shows
If you have ADHD and are considering Mounjaro (tirzepatide), you may be wondering whether this weight loss injection could affect your ADHD symptoms or medications. There is currently no strong evidence that Mounjaro directly treats or worsens ADHD. However, some people report changes in focus or concentration during weight loss treatment, which may relate to appetite suppression, energy levels, or improved metabolic health rather than Mounjaro itself. It's essential to discuss any concerns with your GP before starting, especially if you take ADHD medications like methylphenidate or atomoxetine, as tirzepatide may affect how some oral medications are absorbed.
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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.
How Mounjaro Works and Potential Effects on Focus
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — a once-weekly injectable weight management medication licensed in the UK for adults with a BMI of 30 or above, or 27 or above with weight-related health conditions. It works by activating two natural hormone pathways that regulate appetite, blood sugar, and how quickly food leaves the stomach.
Some people experience changes in concentration or mental clarity during weight loss treatment. This can happen for several reasons: reduced calorie intake may affect energy levels initially; improved blood sugar control can enhance focus; or appetite suppression may reduce distracting hunger signals. Importantly, Mounjaro does not directly target ADHD or dopamine pathways — any changes to focus are typically indirect effects of weight loss and metabolic improvement, not the medication itself.
If you take ADHD medication, inform your prescriber. Mounjaro may slow gastric emptying, potentially reducing how quickly oral medications (including ADHD drugs) are absorbed from the stomach. Your prescriber can assess whether dose adjustments are needed and monitor your response.
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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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ADHD Medications and Mounjaro Interactions
Key ADHD medications to discuss with your prescriber: methylphenidate (Ritalin, Concerta), amphetamines (Adzenys), atomoxetine (Strattera), and guanfacine (Intuniv). All of these are oral medications that depend on absorption in the stomach and small intestine. Because Mounjaro slows gastric emptying — especially at higher doses — there is a potential for reduced absorption of these medications, which could lower their effectiveness.
This does not mean you cannot take Mounjaro with ADHD medication. It means your GP or specialist prescriber must be aware of both treatments and may need to monitor you more closely. You might need a different ADHD medication formulation, adjusted timing of doses, or regular reviews to ensure your ADHD remains well-controlled during tirzepatide treatment. Always provide a complete list of your medications when discussing Mounjaro eligibility.
- 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 make ADHD worse?
There is no evidence that Mounjaro directly worsens ADHD. However, if gastric slowing reduces absorption of your ADHD medication, your ADHD symptoms could worsen due to lower medication levels in your bloodstream. This is why it's crucial to tell your prescriber about all medications you take. They can monitor your response and adjust your treatment plan if needed.
Does Mounjaro help with focus and concentration?
Some people report improved concentration during weight loss, which may relate to better blood sugar control, improved energy levels, or reduced distraction from appetite. However, Mounjaro does not directly treat ADHD. Any improvement in focus is likely an indirect benefit of weight loss and metabolic health, not the medication itself. Results vary between individuals.
Is Mounjaro safe to use with methylphenidate or Concerta?
Mounjaro can be used alongside methylphenidate, but your prescriber must assess the interaction. Mounjaro may slow how quickly methylphenidate is absorbed. Your GP or specialist may need to monitor you more closely or adjust timings. Always inform your prescriber about all medications, including ADHD drugs, before starting tirzepatide.
Should I stop my ADHD medication before starting Mounjaro?
No — do not stop ADHD medication without medical guidance. Instead, discuss both treatments with your GP or the prescriber assessing you for Mounjaro. They can decide whether your ADHD medication needs adjustment or closer monitoring. Stopping ADHD treatment suddenly can be harmful, so any changes must be managed by a healthcare professional.
What should I tell my prescriber about my ADHD?
Tell your prescriber the name of your ADHD medication, the dose you take, how frequently you take it, and how well it currently works for you. Mention any side effects you experience with your ADHD drug. This helps them assess whether Mounjaro is suitable for you and whether any monitoring or adjustments are needed during treatment.
Ready to take control of your weight loss journey?
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