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
How Much Protein Do I Need On Mounjaro?
When taking Mounjaro (tirzepatide), your protein needs don't change significantly, but eating enough protein becomes more important because you're eating less overall food. Most UK adults need around 0.8–1g of protein per kilogram of body weight daily. On Mounjaro, you'll want to prioritise protein-rich foods within your reduced meals to preserve muscle mass during weight loss. Your GP or the healthcare team prescribing your Mounjaro can give personalised advice based on your health. Try our free GLP-1 weight loss calculator to estimate your projected results and plan your nutrition strategy alongside your prescription.
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.
Protein Requirements While Taking Mounjaro
Protein requirements don't change because you're taking Mounjaro — they're based on your body weight and activity level, not your medication. However, because Mounjaro reduces appetite and you'll naturally eat smaller portions, it's crucial to make every calorie count by choosing protein-rich foods.
- Sedentary adults: approximately 0.8g protein per kg of body weight daily
- Moderately active adults: approximately 1.0–1.2g protein per kg of body weight daily
- Regularly exercising adults: approximately 1.2–1.6g protein per kg of body weight daily
On Mounjaro, eating sufficient protein helps preserve lean muscle mass during weight loss, maintains satiety (fullness) longer, and supports your metabolic health. Prioritising protein at each meal — even when portions are smaller — helps prevent muscle loss that can occur with gradual weight management. A UK-licensed prescriber can assess your individual needs based on your activity level and health goals.
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.
Practical Protein Strategies on Mounjaro
Because Mounjaro causes reduced appetite and slower gastric emptying, eating high-protein foods becomes essential. Include lean protein sources like chicken breast, fish, eggs, Greek yoghurt, cottage cheese, and legumes at every meal. If nausea (a common side effect of Mounjaro) makes eating difficult, prioritise easily digested proteins like scrambled eggs, soft fish, or protein-rich broths. Many people find that eating small, frequent high-protein snacks works better than large meals. Track your progress using our free progress tracker to monitor both weight loss and how you're managing your nutrition on Mounjaro. If you struggle to meet your protein target, your GP can discuss whether supplemental protein shakes might help.
- 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 affect how much protein my body needs?
No — Mounjaro doesn't change your baseline protein requirement, which is based on your body weight and activity level. However, because you'll eat less food overall, prioritising protein-rich foods helps preserve muscle during weight loss. Your prescriber can personalise this advice for you.
How do I calculate my exact protein needs on Mounjaro?
Multiply your body weight in kilograms by 0.8–1.6 depending on activity level. For example, a 70kg person doing regular exercise needs approximately 84–112g protein daily. Use our free BMI calculator to confirm your weight, then multiply accordingly.
What if I can't eat enough protein because of Mounjaro nausea?
Nausea is a common Mounjaro side effect (usually improves within weeks). Try softer, easily digestible proteins like scrambled eggs, tinned fish, Greek yoghurt, or bone broth. Protein supplements or shakes may help. Speak to your GP if nausea persists beyond the first month.
Does Mounjaro dose affect how much protein I need?
No — protein requirements don't change based on Mounjaro dose. However, higher doses may cause more appetite reduction, making it even more important to prioritise protein in smaller meals to maintain muscle mass.
Should I use Mounjaro vs Wegovy based on protein needs?
Protein requirements are the same with both medications — both are GLP-1/GIP-based injections that reduce appetite. Mounjaro is a dual GIP and GLP-1 agonist, while Wegovy is a GLP-1 agonist only. Your prescriber will assess which is suitable for you based on clinical assessment, not protein intake.
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.