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 and Thrush — UK Patient Guide
Thrush (candidiasis) is not listed as a common side effect of Mounjaro in UK clinical trials, but some patients report experiencing yeast infections whilst taking this tirzepatide injection. Because Mounjaro may affect how quickly food leaves your stomach and can influence blood sugar levels, there may be indirect mechanisms that could increase thrush risk in certain individuals. This guide explains what you need to know about Mounjaro, thrush, and when to contact your GP if you develop symptoms. Our GLP-1 weight loss calculator can help you understand potential outcomes with tirzepatide, and our free BMI calculator provides context for your personal health needs.
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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 Might Increase Thrush Risk
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist approved by the MHRA for UK weight management. Whilst thrush is not formally listed as a common side effect in the product information, there are plausible biological mechanisms that could increase yeast infection risk:
- Delayed gastric emptying: Mounjaro slows stomach emptying, which may affect the balance of gut bacteria and increase candida growth
- Blood sugar changes: Candida thrives in high-sugar environments; any fluctuation in blood glucose control could theoretically increase infection risk
- Nausea and reduced food intake: Gastrointestinal side effects may alter your microbiome balance
- Individual variation: Some patients are naturally more prone to thrush due to genetics, immune function, or vaginal flora balance
If you develop symptoms of thrush whilst taking Mounjaro, contact your GP. Never stop Mounjaro without medical advice.
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.
Recognising Thrush Symptoms and Seeking Help
Symptoms of thrush include: vaginal itching, burning, or thick white discharge (women); redness, itching, or discharge under the foreskin (men); oral thrush with white patches on the tongue or throat; or skin rashes in warm, moist areas. Thrush is not serious but should be a UK pharmacy promptly to prevent recurrence.
Contact your GP if you suspect thrush — diagnosis is straightforward and treatment (usually antifungal cream or tablets) is highly effective. Your prescriber should also know you're taking Mounjaro, as some antifungal medications do not interact with tirzepatide. Keep a symptom log and mention any recurring infections, as your GP may suggest adjustments to your Mounjaro dose or additional preventative measures.
- 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.
Is thrush a common side effect of Mounjaro?
Thrush is not listed as a common side effect in MHRA-approved Mounjaro information. However, some UK patients report yeast infections whilst taking tirzepatide. If you develop symptoms, contact your GP promptly. Thrush is treatable and not a reason to stop Mounjaro without medical guidance.
Can Mounjaro cause thrush in men?
Yes, men can develop thrush whilst taking Mounjaro, though it's less common than in women. Symptoms include redness, itching, or discharge under the foreskin. Seek GP advice if you notice these signs. Antifungal creams or tablets are effective treatments.
Should I stop Mounjaro if I get thrush?
No — do not stop Mounjaro without contacting your prescriber. Thrush is treatable with antifungal medication and does not require stopping your tirzepatide injection. Your GP can advise whether your dose needs adjustment or if preventative measures would help.
How do I prevent thrush whilst taking Mounjaro?
Keep skin dry, wear breathable clothing, avoid douching, and maintain good hygiene. If you're prone to thrush, your GP may recommend preventative antifungal medication. Ensure your blood sugar is well-controlled and discuss any recurring infections with your healthcare team.
Can I take antifungal medication with Mounjaro?
Most antifungal treatments (creams, tablets, oral fluconazole) are safe with Mounjaro. Always inform your GP that you're taking tirzepatide so they can check for interactions. Mounjaro may slightly delay absorption of some oral medications, but antifungals are generally not affected.
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.