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 Kwikpen 10mg vs Wegovy — What's the Difference?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight loss injections licensed in the UK. The 10mg Mounjaro Kwikpen dose represents a mid-range escalation in tirzepatide therapy. While both medications help support weight management alongside diet and physical activity, they work differently and have distinct dosing schedules. This guide compares the two on mechanism, doses, expected outcomes, and how your prescriber might determine which is more suitable for you. Use our GLP-1 weight loss calculator to explore potential outcomes, and our BMI calculator to understand your starting point.
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.
Mechanism, Doses, and Trial Data Comparison
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — it activates two natural hormone pathways, which is why it differs from other weight loss injections. The 10mg Kwikpen dose sits in the mid-escalation range; the maximum dose is 15mg weekly. SURMOUNT-1 clinical trial data showed that at 15mg (not 10mg), tirzepatide helped participants lose an average of approximately 20.9% of their body weight over 72 weeks.
Wegovy (semaglutide) is a GLP-1-only receptor agonist — it activates a single hormone pathway. The maximum Wegovy dose is 2.4mg weekly. STEP-1 trial data showed semaglutide at 2.4mg helped participants lose an average of approximately 14.9% of body weight over 68 weeks. Important: individual results vary significantly, and weight loss requires concurrent lifestyle changes including reduced-calorie diet and increased physical activity.
- Mounjaro doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg (escalated over weeks)
- Wegovy doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg (escalated over weeks)
- Both are once-weekly injections delivered via pre-filled pen
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.
Side Effects, Eligibility, and How Your Prescriber Decides
Both medications carry similar common side effects: nausea, diarrhoea, vomiting, constipation, and stomach pain are most frequent, typically improving with time. Injection site reactions, fatigue, and decreased appetite are also possible. Both require the same UK eligibility criteria: BMI 30 or above, or BMI 27–29.9 with a weight-related health condition (type 2 diabetes, high blood pressure, cardiovascular disease, or sleep apnoea). For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply.
Your prescriber will assess which medication suits you based on your medical history, any other medications you take, tolerance to side effects, and treatment goals. Neither medication is "better" — suitability is individual. Some prescribers may prefer the dual mechanism of Mounjaro; others may choose Wegovy based on your specific health profile. Both require prescription through NHS specialist services or private online prescribing with clinical assessment.
- 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 does the 10mg Mounjaro Kwikpen dose mean?
The 10mg Kwikpen contains a single 10mg dose of tirzepatide for one weekly injection. It's a mid-range dose in Mounjaro's escalation schedule (doses go from 2.5mg up to 15mg). Most patients on Mounjaro eventually move to a maintenance dose; 10mg is often effective, though some prescribers escalate further depending on response and side effects.
Is Mounjaro 10mg more effective than Wegovy?
Clinical trials showed Mounjaro 15mg (the maximum dose) produced slightly higher average weight loss than Wegovy 2.4mg (the maximum Wegovy dose). However, these are averages — individual results vary widely. Neither medication assures a specific outcome. Your prescriber will choose based on your personal health factors, not trial averages alone.
Can I switch from Wegovy to Mounjaro Kwikpen?
Yes, switching between medications is possible and managed by your prescriber. There is no official established conversion chart — switching requires clinical assessment and timing. You cannot simply switch doses week-to-week; your prescriber will give specific instructions on timing and any transition period needed.
What are the common side effects of Mounjaro 10mg?
The most common side effects are nausea, diarrhoea, vomiting, constipation, and stomach pain. These typically improve after the first few weeks as your body adjusts. Less common are injection site reactions, fatigue, headache, and dizziness. Serious side effects are rare but seek urgent medical attention if you experience severe stomach pain, signs of allergic reaction, or gallbladder problems.
How do I access Mounjaro Kwikpen 10mg in the UK?
Mounjaro is prescription-only. NHS access is through specialist tier 3 weight management services (usually requires GP referral); availability and waiting times vary by region. Private access is available through GPhC-registered online pharmacies following a clinical assessment by a UK-licensed prescriber. Your prescriber will determine which dose is appropriate for you after evaluation.
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.