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
Does Mounjaro Cause Low Blood Pressure?
Mounjaro (tirzepatide) doesn't directly cause low blood pressure as a primary side effect, but some people may experience blood pressure changes during treatment. Understanding how Mounjaro and Wegovy (semaglutide) affect cardiovascular parameters is important if you're considering either medication. Both are prescription-only weight management injections licensed in the UK, and both require a clinical assessment before use. Your prescriber will review your current blood pressure and medications to determine which option is suitable for you.
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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.
How Mounjaro and Wegovy Affect Blood Pressure
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways. In clinical trials like SURMOUNT-1, blood pressure improvements were observed in participants taking tirzepatide — averaging around 2–3 mmHg reduction in systolic pressure. This is generally considered beneficial for weight management, as excess weight often contributes to elevated blood pressure.
Wegovy (semaglutide) is a GLP-1 receptor agonist only, with a single hormone mechanism. STEP trials showed similar or slightly smaller blood pressure reductions compared to Mounjaro. Both medications' effects on blood pressure appear to be secondary benefits related to weight loss itself, not direct blood pressure-lowering actions.
- Weight loss typically improves blood pressure naturally
- Neither medication is designed as a blood pressure treatment
- Individual responses vary significantly
- Some people report dizziness early in treatment (possible but uncommon)
Clinically BackedWeight Loss
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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.
Which Medication Might Be Right for You?
Choosing between Mounjaro and Wegovy depends on your individual health profile, not just blood pressure considerations. Your GP or a licensed prescriber will assess factors including your current blood pressure readings, any existing blood pressure medications you take, your BMI, weight-related health conditions, and any contraindications. Both medications may interact with certain blood pressure drugs — oral contraceptives, sulphonylureas, and other medications should all be discussed during your consultation. Use our GLP-1 weight loss calculator to estimate potential outcomes with either medication, and talk to your prescriber about which option aligns best with your cardiovascular health goals.
- 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 cause dangerously low blood pressure?
No. Mounjaro does not directly cause hypotension (dangerously low blood pressure) as a known side effect. Some people may experience mild dizziness early in treatment, but this is typically related to dose adjustment or dehydration rather than blood pressure dropping too low. Always inform your prescriber if you experience persistent dizziness or fainting.
Is Mounjaro safe if I already take blood pressure medication?
Yes, but requires prescriber oversight. Many people taking Mounjaro also use blood pressure medications like ACE inhibitors or beta-blockers. Your prescriber may need to monitor your blood pressure more closely when starting, as weight loss can gradually lower your reading. Never stop blood pressure medication without medical advice.
Does Wegovy lower blood pressure more than Mounjaro?
Clinical trials suggest Mounjaro and Wegovy have similar blood pressure effects — both show modest improvements averaging 2–3 mmHg systolic reduction. These improvements appear linked to weight loss rather than the medications directly lowering pressure. Individual results vary, and prescriber assessment is essential for personalised suitability.
What cardiovascular side effects should I watch for?
Serious cardiovascular side effects are rare with both medications. Seek urgent medical attention for: chest pain, shortness of breath, rapid or unusual heartbeat, or fainting. Mild dizziness or headache early in treatment is more common and often temporary. Report any persistent symptoms to your GP.
Which medication is better if I have heart disease history?
Both Mounjaro and Wegovy can be used by people with cardiovascular history, as weight loss generally benefits heart health. However, your specific diagnosis, medications, and prescriber assessment determine suitability. Discuss your full cardiovascular history during your clinical assessment — your prescriber will guide you toward the safest option. ```
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.