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 To Make Mounjaro Work Better
Mounjaro (tirzepatide) works best when combined with sustained lifestyle changes—diet, exercise, and hydration all play a crucial role. While clinical trials showed impressive weight loss results, individual outcomes depend significantly on how you support the medication with daily habits. This guide covers practical, evidence-based strategies to help you get the most from your tirzepatide treatment, whether you're accessing it through NHS specialist services or a private UK 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.
Lifestyle Changes That Amplify Mounjaro Effectiveness
Mounjaro is most effective when paired with a reduced-calorie diet and regular physical activity—exactly as used in clinical trials. A calorie deficit of 500 kcal per day typically supports around 0.5 kg weight loss weekly. Focus on protein-rich foods (which help preserve muscle during weight loss), whole grains, and plenty of vegetables. Many people find that Mounjaro naturally suppresses appetite, but eating smaller, nutrient-dense meals prevents nutritional deficiencies.
- Consistency matters more than perfection—sustainable eating habits beat strict restriction
- Strength training (2–3 times weekly) helps preserve muscle mass as you lose fat
- Walking or moderate cardio (150 minutes weekly) supports cardiovascular health alongside weight loss
- Sleep quality affects hunger hormones and weight loss—aim for 7–9 hours nightly
Use our free GLP-1 weight loss calculator to estimate potential weight loss at your current dose, then adjust your target based on these lifestyle factors.
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 Tips to Support Your Mounjaro Treatment
Hydration is essential—Mounjaro can cause nausea and constipation, and dehydration worsens both. Aim for 2 litres of water daily. Eat slowly and chew thoroughly; Mounjaro slows gastric emptying, so rushing meals increases nausea risk. If side effects feel overwhelming, speak to your prescriber—dose adjustments or timing changes can help. Track your progress with our free progress tracker to identify patterns: which foods cause nausea? When do you feel fullest? This data helps you refine your approach over time.
Remember that results vary individually—some people see significant loss quickly, others progress more gradually. Weight loss injections are a tool to support your efforts, not a replacement for them.
- 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.
How long does it take to see results with Mounjaro?
Clinical trials showed measurable weight loss by week 8–12. However, individual timelines vary—some people notice appetite changes within days, while weight loss may take several weeks. Each dose increase (every 4 weeks) may provide additional benefits. Consistency with diet and exercise accelerates results.
Does diet matter if I'm taking Mounjaro?
Yes, significantly. Mounjaro helps suppress appetite and cravings, but you still need a calorie deficit to lose weight. The medication makes this easier—you may feel full on smaller portions—but eating highly processed, calorie-dense foods can slow progress. Focus on whole foods, protein, and vegetables.
Can I lose weight on Mounjaro without exercise?
Diet is the primary driver of weight loss, so exercise isn't strictly required. However, adding even 150 minutes of moderate activity weekly (brisk walking, swimming) preserves muscle mass, improves cardiovascular health, and often accelerates results. Strength training is especially helpful during weight loss.
What should I do if Mounjaro stops working?
"Plateaus" are common—your body adapts over time. First, check your calorie intake (using an app like MyFitnessPal); many people unconsciously increase portions as appetite suppression wears off. Second, your prescriber can assess whether a dose increase is appropriate. Third, vary your exercise routine—this can restart progress.
Should I change my diet when I increase my Mounjaro dose?
Not necessarily—your prescriber will adjust your dose gradually (every 4 weeks minimum), giving your body time to adapt. Your appetite suppression may increase with each dose, meaning smaller portions feel satisfying. Listen to your body and adjust food intake based on hunger, not a fixed meal plan.
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.