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
Is Mounjaro an appetite suppressant?
Mounjaro is not technically a traditional appetite suppressant, but it works in a similar way by activating two natural hormone pathways that help regulate hunger and fullness. The medication contains tirzepatide, a dual GIP and GLP-1 receptor agonist that may help reduce food cravings and support feeling fuller after smaller meals. Unlike older appetite suppressants, Mounjaro works with your body's natural hunger signals rather than simply blocking them. It's a prescription-only medicine licensed in the UK for weight management in adults who meet specific eligibility criteria.
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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 works on appetite and hunger
Mounjaro is a dual GIP and GLP-1 receptor agonist. Rather than simply suppressing appetite, it activates two natural hormone pathways your body already uses to control hunger and satiety. GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) are hormones produced in the gut after eating that signal fullness to the brain. By mimicking and amplifying these signals, Mounjaro may help you:
- Feel fuller for longer after eating
- Reduce cravings and desire to eat between meals
- Feel satisfied with smaller meal portions
- Have less interest in high-calorie or sugary foods
This is different from older appetite suppressants that work through stimulant effects. Mounjaro works with your natural biology, which is why it's considered safer and more sustainable. The medication also slows gastric emptying (how quickly food leaves the stomach), though this effect typically reduces over time as your body adjusts.
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.
Clinical evidence and expected results
In the SURMOUNT clinical trials, Mounjaro demonstrated significant appetite reduction and weight loss results. At the maximum dose of 15 mg weekly, participants lost an average of approximately 20.9% of their body weight over 72 weeks alongside a reduced-calorie diet and increased physical activity. Individual results vary considerably — some people experience strong appetite suppression while others experience more modest effects. Your response depends on factors including your starting weight, metabolism, adherence to lifestyle changes, and how your body responds to the medication. A prescriber will monitor your progress and may adjust your dose based on your individual response and tolerability.
- 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 Mounjaro the same as a traditional appetite suppressant?
Not exactly. Traditional appetite suppressants like older stimulant-based drugs simply block hunger signals. Mounjaro works differently — it activates natural hormone pathways (GIP and GLP-1) that regulate appetite more gently. This natural mechanism is considered safer and more sustainable for long-term weight management.
How long does Mounjaro take to work on appetite?
Many people notice reduced appetite and food cravings within the first 1–2 weeks of starting Mounjaro, though full effects typically develop over several weeks as your dose is gradually increased. Maximum appetite suppression usually occurs after reaching your maintenance dose.
What's the difference between Mounjaro and Wegovy for appetite control?
Mounjaro is a dual GIP + GLP-1 agonist, while Wegovy is a single GLP-1 agonist. Both reduce appetite, but Mounjaro's dual mechanism may provide stronger appetite suppression for some people. Clinical trials show both are effective, though individual responses vary significantly.
Can I use our GLP-1 weight loss calculator to estimate results on Mounjaro?
Yes. Our free weight loss calculator above helps project potential weight loss at different Mounjaro doses based on clinical trial data. Remember these are estimates — your actual results depend on your personal effort with diet and exercise alongside the medication.
Will my appetite return to normal if I stop taking Mounjaro?
Most people find appetite increases gradually after stopping Mounjaro, returning to baseline levels over a few weeks. This is why weight management after stopping the medication requires sustained lifestyle changes. Your GP or prescriber can advise on the best approach for your situation.
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.