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 Thrush?
Thrush is not listed as a common side effect of Mounjaro (tirzepatide) in UK clinical trials or the official prescribing information. However, any changes to your digestive system or blood sugar levels while taking weight loss medication could theoretically increase infection risk. If you experience symptoms of thrush—such as itching, white patches, or discharge—while taking Mounjaro, contact your GP immediately for assessment and treatment. Individual responses to medication vary, and your healthcare provider can give you personalised advice.
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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 Works and Infection Risk
Mounjaro is a dual GIP and GLP-1 receptor agonist that works by mimicking natural hormones to regulate appetite and blood sugar levels. The way it works—slowing gastric emptying and affecting glucose metabolism—could theoretically create an environment where fungal infections like thrush become more likely, though this is not a proven direct link.
Thrush occurs when Candida yeast overgrows, often triggered by:
- Changes in blood sugar levels (high glucose favours Candida growth)
- Disruptions to the normal balance of gut bacteria
- Slower digestive transit time, which may affect the microbiome
- Oral thrush can also be a complication in people with poorly controlled diabetes
If you're taking Mounjaro through an NHS specialist service or private prescription in the UK, your prescriber should monitor you for any unusual symptoms. Report any suspected thrush symptoms to your GP without delay—thrush is easily treatable with antifungal medication.
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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 Suspect Thrush While on Mounjaro
If you develop symptoms suggestive of thrush—genital itching, white coating on the tongue, unusual discharge, or vaginal burning—contact your GP as soon as possible. Do not stop taking Mounjaro without medical advice. Your GP can diagnose thrush through examination or swab and prescribe appropriate antifungal treatment, such as fluconazole or a topical antifungal cream.
In the meantime, you can help reduce fungal overgrowth by maintaining good hygiene, avoiding tight clothing, limiting sugary foods, and staying hydrated. If thrush symptoms are severe or recurrent while on Mounjaro, inform your prescriber—they may need to review your treatment plan. Keep a record of any side effects and share this with your healthcare team at your next check-in.
- 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 known side effect of Mounjaro in the UK?
Thrush is not listed as a common or very common side effect in UK clinical trials or the Mounjaro product information. However, any medication affecting digestion or blood sugar could indirectly increase infection risk. If you experience thrush symptoms, contact your GP for assessment and treatment.
Why might Mounjaro increase the risk of thrush?
Mounjaro slows gastric emptying and affects glucose metabolism. High blood sugar and changes to gut bacteria can favour Candida yeast overgrowth. However, this is a theoretical risk, not a proven direct effect. Your individual risk depends on many factors.
What are the symptoms of thrush I should watch for?
Oral thrush: white patches on the tongue or mouth, soreness, difficulty swallowing. Genital thrush: itching, white or cream-coloured discharge, burning during urination. If you notice any of these while on Mounjaro, contact your GP promptly.
Should I stop taking Mounjaro if I develop thrush?
No—do not stop Mounjaro without medical guidance. Contact your GP to confirm thrush and start antifungal treatment. Your prescriber can advise whether to continue or adjust your Mounjaro dose based on your individual health.
How is thrush a UK pharmacy in people on weight loss medication?
Thrush is typically a UK pharmacy with antifungal medications: fluconazole (oral tablet), clotrimazole (topical cream), or miconazole (oral gel). Your GP will choose the most appropriate option. These treatments work alongside Mounjaro and do not usually require stopping your injection.
Ready to take control of your weight loss journey?
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