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
Mounjaro Hacks: Practical Tips for Better Results
If you're taking Mounjaro in the UK, understanding practical strategies can help you manage side effects, stick to your treatment plan, and support better outcomes. This guide covers evidence-based tips and real-world strategies that may help you get the most from tirzepatide whilst managing the injection schedule, dietary changes, and lifestyle adjustments needed for sustainable weight loss.
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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.
Managing Side Effects and Optimising Your Experience
Mounjaro side effects — particularly nausea, diarrhoea, and constipation — are very common in the first few weeks. Here are practical strategies: eat smaller, more frequent meals rather than three large ones; choose bland, easily digestible foods (plain rice, toast, lean protein); stay hydrated with water and electrolyte drinks; ginger tea or peppermint may help with nausea; over-the-counter remedies like loperamide can help with diarrhoea if needed (discuss with your GP first); and ensure adequate fibre intake to prevent constipation. Many users find side effects improve significantly after 4–8 weeks as your body adjusts. Keep a simple food diary to identify trigger foods that worsen symptoms. Take your time eating — slower pace may reduce stomach discomfort. If side effects are severe or persistent beyond 12 weeks, discuss dose adjustment with your prescriber rather than stopping treatment.
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.
Injection Technique and Storage Best Practices
The Mounjaro KwikPen is straightforward to use, but technique matters. Always inject into clean, dry skin; rotate injection sites weekly (stomach, thigh, or upper arm) to prevent lipohypertrophy (thickened skin from repeated injections); let the pen warm to room temperature for 30 minutes before injecting — this reduces injection discomfort; count slowly to 3 after pressing the injection button to ensure full dose delivery. Store unopened pens in the fridge at 2–8°C; after first use, you can keep at room temperature (below 30°C) for up to 30 days. Set phone reminders for your weekly injection day to avoid missed doses. If you miss a dose within 4 days, take it as soon as remembered; if more than 4 days have passed, skip and take your next scheduled dose.
- 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.
What's the best time of week to take Mounjaro?
There's no "best" time — consistency matters more than timing. Choose a day that fits your routine and take it at roughly the same time each week. Many people pick Monday or Sunday for easy remembering. Set a phone reminder to avoid missing doses, which could interrupt your progress.
Can I switch between injection sites to reduce discomfort?
Yes, rotating sites is essential. Alternate between stomach, thighs, and upper arm each week. This prevents lipohypertrophy (thickened skin patches) and reduces injection site reactions. Always inspect skin before injecting and avoid areas with bruising or irritation.
Does eating smaller meals really help with nausea on Mounjaro?
Yes. Mounjaro slows stomach emptying, so large meals are harder to manage. Eating 4–6 small meals daily instead of three large ones significantly reduces nausea for most users. Focus on protein and avoid fatty or spicy foods in the first 4–8 weeks.
Should I adjust my diet straight away when starting Mounjaro?
Starting gradually with dietary changes works better than a dramatic overhaul. Begin with portion control and focus on protein-rich, nutrient-dense foods. Use our GLP-1 weight loss calculator to track realistic projections, and combine medication with sustainable eating habits rather than extreme restriction.
What should I do if I experience severe constipation on Mounjaro?
Increase water intake to at least 2–3 litres daily, add fibre gradually (oats, vegetables), and consider a gentle stool softener if needed — discuss options with your GP. Gentle movement and exercise also help. If constipation persists beyond 2–3 weeks, contact your prescriber about possible dose adjustment.
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.