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
Can Mounjaro Give You Thrush?
Thrush (Candida yeast infection) is not listed as a known side effect of Mounjaro in the official UK prescribing information or MHRA guidance. However, some people taking tirzepatide have reported yeast infections. This may be an indirect effect rather than a direct side effect. If you're considering Mounjaro or currently taking it and experiencing symptoms, your GP can assess whether any infections are related to the medication or other causes.
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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 Yeast Infection Risk
While thrush isn't formally listed as a side effect of Mounjaro in the UK prescribing data, there are indirect mechanisms that could increase yeast infection risk. Mounjaro (tirzepatide) slows gastric emptying and affects how the body processes nutrients, which may influence the gut microbiome—the community of bacteria that naturally prevents Candida overgrowth. Additionally, if Mounjaro causes nausea, vomiting, or diarrhoea (very common side effects), these gastrointestinal changes can disrupt the balance of protective bacteria. Some people report increased infection risk when taking GLP-1 medications like tirzepatide, though this is not a formally documented adverse effect. Weight loss itself may also temporarily affect immune function. If you're taking Mounjaro and develop symptoms of thrush—such as itching, white patches in the mouth, or unusual vaginal discharge—contact your GP promptly for assessment and appropriate treatment.
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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.
What to Do If You Experience Thrush on Mounjaro
If you notice thrush symptoms while taking Mounjaro:
- Contact your GP or call 111 for advice—thrush is treatable and common
- Do not stop taking Mounjaro without speaking to your prescriber first
- Your GP can prescribe antifungal treatment (tablets, creams, or lozenges depending on the type of thrush)
- Keep your prescriber informed of any new symptoms to help them assess whether they're related to the medication
Thrush is manageable and should not prevent you from continuing Mounjaro if it's otherwise suitable for you. Your healthcare team can help you balance the benefits of the medication against any side effects experienced.
- 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 in the UK?
Thrush is not listed as a known side effect of Mounjaro in the official MHRA prescribing information. However, some people taking tirzepatide report yeast infections, possibly due to indirect effects on gut bacteria or immune function. If you're concerned, discuss it with your GP.
How does Mounjaro affect the risk of getting thrush?
Mounjaro slows digestion and may alter gut bacteria balance, which normally protects against Candida overgrowth. Gastrointestinal side effects like diarrhoea can also disrupt this protective barrier. These indirect mechanisms may increase thrush risk in some individuals.
Should I stop Mounjaro if I get thrush?
No—do not stop Mounjaro without consulting your prescriber. Thrush is treatable with antifungal medication and should not require stopping the injection. Your GP can prescribe appropriate treatment whilst you continue tirzepatide.
What are the symptoms of thrush I should watch for?
Oral thrush: white patches in the mouth, difficulty swallowing, or sore throat. Vaginal thrush: itching, burning, white discharge. Skin thrush: rashes in skin folds. Contact your GP if you notice these symptoms whilst taking Mounjaro.
Can I use the BMI calculator to check my health context with Mounjaro?
Yes—use our free BMI calculator to see your current health context and healthy weight range alongside your Mounjaro treatment. This helps you track whether your weight management is progressing as expected during treatment.
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.