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
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Mounjaro Every 6 Days — UK Dosing Information
Mounjaro (tirzepatide) is designed as a once-weekly injection, and the standard UK dosing schedule requires injections seven days apart. Taking Mounjaro every 6 days is not recommended and falls outside the approved dosing guidelines. This guide explains the correct UK dosing schedule for Mounjaro, how the dose titration works, and what happens if you miss or delay a dose. If you're considering weight management treatment in the UK, our free BMI calculator can help you check whether you might be eligible for prescription options.
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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.
UK Dosing Schedule and Dose Titration
Mounjaro is approved in the UK as a once-weekly injection, with doses given exactly 7 days apart. The standard dose titration schedule works as follows: start at 2.5 mg in weeks 1–4, increase to 5 mg in weeks 5–8, then escalate through 7.5 mg, 10 mg, 12.5 mg, and up to the maximum 15 mg dose. Each dose increase requires a minimum of 4 weeks at the previous dose level.
Taking Mounjaro every 6 days would disrupt this carefully designed pharmacokinetic schedule and is not recommended by MHRA guidance. The medicine is formulated to maintain steady levels in your body when dosed weekly. Shortening the interval between injections may lead to unpredictable drug levels and increase the risk of side effects.
- Standard interval: exactly 7 days between doses
- Minimum time between doses: 72 hours (3 days)
- Do not reduce the standard 7-day interval without prescriber guidance
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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.
Missed or Delayed Doses — What to Do
If you miss a Mounjaro dose, UK clinical guidance advises: if you remember within 4 days of the missed injection, take it as soon as possible and continue your normal weekly schedule from there. If more than 4 days have passed, skip that dose and take your next injection on the normal scheduled day. Never inject two doses close together to "catch up."
Occasional minor delays (a day or two) are unlikely to cause harm, but consistently injecting every 6 days rather than 7 would alter your treatment plan. If you're struggling with the weekly schedule, discuss this with your GP or prescriber — they may adjust your dose or explore alternatives. Use our GLP-1 weight loss calculator to track your expected progress at the correct dosing schedule, and our progress tracker to log your actual results.
- 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 Mounjaro every 6 days to speed up weight loss?
No. Mounjaro is specifically approved and formulated for once-weekly dosing (7 days apart). Taking it more frequently is not recommended, may increase side effects, and is not supported by UK MHRA or NHS guidance. Always follow your prescribed schedule and discuss any concerns with your GP.
What if I accidentally inject Mounjaro 6 days instead of 7 days apart?
A single occurrence of injecting one day early is unlikely to cause serious harm, but should be avoided. Adjust your next dose back to the standard 7-day interval. If this happens repeatedly, contact your prescriber to clarify your dosing schedule and ensure you're using it safely.
Does taking Mounjaro every 6 days provide faster weight loss?
No evidence supports this. Clinical trials used the standard 7-day dosing schedule, which is what tirzepatide is designed for. Faster dosing does not improve weight loss and increases the risk of nausea, vomiting, and other side effects without additional benefit.
How do I remember to take Mounjaro on the same day each week?
Set a phone reminder for the same day and time each week. Some people inject on a Monday, others on a Friday — pick a day that fits your routine. Keep a simple calendar or use our free progress tracker to log each injection and stay on schedule.
What if I want to change my injection day from weekly to a different schedule?
Discuss this with your GP or the prescriber who manages your Mounjaro. Do not change your dosing schedule independently. Your prescriber can help you adjust to a different day of the week if needed, but the 7-day interval between doses is standard and important for safety and effectiveness.
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.