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
ADHD Medications and Weight Loss — What You Need to Know
Some ADHD medications can affect appetite and weight, and many people taking them wonder about weight management options. If you're concerned about weight change related to ADHD treatment, you're not alone — this is a recognised side effect of certain stimulant medications. The good news is that several prescription weight loss options are now available in the UK for eligible adults. Understanding what's available, how they work, and whether you might be eligible can help you have an informed conversation with your GP about your health and weight management goals.
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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.
UK-Licensed Prescription Weight Management Options
For adults who need support with weight management in the UK, three prescription options are currently licensed: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All work by activating GLP-1 hormone pathways (or dual GIP and GLP-1 pathways in Mounjaro's case) to help reduce appetite and support feeling fuller after eating.
Clinical evidence shows these medications can be effective: in trials, patients lost an average of 15–21% of their body weight over several months, though individual results vary significantly. Mounjaro and Wegovy are once-weekly injections, while Saxenda is a daily injection. All are prescription-only and require a clinical assessment before being prescribed. Eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Use our free GLP-1 weight loss calculator to see what potential results might look like at different doses.
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.
Accessing Weight Management Support — NHS and Private Routes
In the UK, prescription weight loss medication can be accessed through two main routes. NHS access is through specialist tier 3 weight management services — you'll need a referral from your GP, and availability and waiting times vary significantly by region. Private access is available through UK-licensed prescribers via online consultations, with prescription dispensing by GPhC-registered pharmacies, typically without NHS referral.
If you're taking ADHD medication and concerned about weight, your first step should be a conversation with your GP. They can discuss whether your current ADHD medication is contributing, whether dose adjustment is possible, and what weight management options might be suitable for you. Your GP can also refer you to specialist services if needed. Check your BMI using our free BMI calculator to understand your starting point — this information will help guide the conversation.
- 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 I take ADHD medication and weight loss medication together?
This depends on your specific medications and medical history. Some ADHD medications and weight loss medications can interact, so it's essential to inform your prescriber about all medications you're taking. Your GP or specialist can assess safety and adjust doses if needed. Never stop or change ADHD medication without medical guidance.
Will stopping ADHD medication help me lose weight?
This is a decision to make only with your GP. Stopping ADHD medication because of weight concerns isn't usually recommended — ADHD treatment is important for many people's wellbeing and function. Instead, discuss weight management options that work alongside your ADHD treatment. Your GP can help you weigh the benefits and risks.
How long does it take to see weight loss results with GLP-1 medication?
In clinical trials, meaningful weight loss typically begins within 4–8 weeks, with more significant results by 12–16 weeks. However, individual timelines vary. Weight loss is gradual and usually requires at least 12 weeks of consistent treatment to see substantial results. Results are best with dietary changes and increased physical activity.
What's the difference between Mounjaro, Wegovy, and Saxenda?
Mounjaro is a dual GIP and GLP-1 agonist (once weekly), Wegovy is a GLP-1 agonist (once weekly), and Saxenda is a GLP-1 agonist (daily injection). In clinical trials, Mounjaro showed slightly higher average weight loss (15–21%) than Wegovy (around 15%), but all three are effective. Your prescriber will assess which suits you best.
Is prescription weight loss medication available on the NHS?
Yes, tirzepatide (Mounjaro) and semaglutide (Wegovy) are now approved by NICE for use within NHS specialist weight management services. However, NHS access requires a referral to tier 3 services and availability varies by region — waiting lists can be lengthy in many areas. Private access is faster but involves cost.
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.