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 Medications and Weight Loss — A UK Health Guide
ADHD medications, particularly stimulant-based treatments, can affect appetite and weight in different ways. Some people experience weight loss, whilst others gain weight or see no change. This guide explains how ADHD meds influence weight, when to discuss concerns with your GP, and what evidence-based weight management options are available in the UK — including prescription weight loss medication if appropriate. Understanding these connections helps you make informed health decisions.
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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 ADHD Medications Affect Weight
Stimulant medications (methylphenidate, amphetamine-based treatments like Adderall and Elvanse) work by increasing dopamine and noradrenaline in the brain, which can suppress appetite and increase metabolism. This may result in weight loss, particularly in the first few weeks of treatment. However, effects vary significantly between individuals.
Non-stimulant ADHD medications (atomoxetine, guanfacine) typically have less impact on appetite, though weight changes remain possible.
- Some people experience significant appetite suppression — eating less without conscious effort
- Others find appetite returns to normal after initial adjustment (weeks to months)
- A small percentage may experience weight gain despite stimulant use
- Long-term weight change on ADHD meds is often modest or neutral
If you're concerned about weight changes on ADHD medication, discuss this with your GP or prescribing specialist. Never adjust or stop ADHD medication without medical guidance — the benefits for ADHD management typically outweigh weight concerns.
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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.
Weight Management Options if You Have ADHD
If you're managing both ADHD and weight concerns, several evidence-based approaches are available. Your GP can help you explore dietary strategies, physical activity plans tailored to ADHD (structured routines often work better), and behavioural support through NHS weight management services.
For adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure, prescription weight loss medication may be appropriate. GLP-1 weight loss injections such as Wegovy (semaglutide) and Mounjaro (tirzepatide) are licensed in the UK for weight management. These can be used alongside ADHD treatment, though your GP should assess any medication interactions. Use our free BMI calculator above to check your personal BMI, and our GLP-1 weight loss calculator can help you estimate potential outcomes with prescription medication.
- 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.
Do all ADHD medications cause weight loss?
No. Stimulant ADHD medications often reduce appetite initially, but effects vary widely. Some people experience modest weight loss, others see no change, and a few gain weight. Non-stimulant ADHD medications typically have less impact on weight. Long-term effects are often neutral. Always discuss weight concerns with your GP — never stop ADHD medication without guidance.
Is it safe to use ADHD medication and weight loss injections together?
This depends on individual circumstances and which specific medications you're taking. GLP-1 injections like Wegovy and Mounjaro are prescription-only and require clinical assessment. A prescriber will review all your medications, including ADHD treatment, before deciding if weight loss medication is appropriate. Your GP can provide personalised guidance on safe combinations.
How long does appetite suppression last when starting ADHD medication?
Initial appetite suppression typically lasts weeks to a few months as your body adjusts. For some people, appetite normalises after initial adjustment. For others, the effect persists. Weight change during this period varies — some lose weight, others maintain. If appetite changes are concerning, discuss timing and expectations with your prescriber.
Can I manage ADHD and weight loss at the same time?
Yes. Many people successfully manage both. Your GP can help coordinate ADHD treatment with evidence-based weight management, such as structured dietary support, NHS weight management programmes, or (if eligible) prescription weight loss medication. Routine and structure — often beneficial for ADHD management — also support sustainable weight loss.
What should I do if I've gained weight despite taking stimulant ADHD medication?
Weight gain on stimulant medication is less common but can happen. Discuss this with your GP or prescribing specialist — they may adjust your medication, explore underlying factors (like emotional eating or sleep issues related to ADHD), or refer you to weight management services. Never stop your ADHD medication without medical guidance.
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.