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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Can Mounjaro Help With PCOS Weight Management in the UK?
Polycystic ovary syndrome (PCOS) is a common condition affecting many women in the UK, often linked to weight gain and difficulty losing weight. Mounjaro (tirzepatide) is a prescription weight management injection that may help support weight loss in people with PCOS, particularly those who struggle with insulin resistance. This guide explains how Mounjaro works, who may be eligible, and what to expect if you're considering this treatment option. Our GLP-1 weight loss calculator can help you explore potential outcomes with weight loss medication. Always speak with your GP before starting any new treatment, especially if you have PCOS or related health conditions.
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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 May Help With PCOS
PCOS is often associated with insulin resistance — the body becomes less responsive to insulin, leading to higher insulin levels. This can trigger increased appetite, fat storage around the abdomen, and weight gain. Mounjaro (tirzepatide) works differently from standard weight loss injections: it's a dual GIP and GLP-1 receptor agonist, meaning it activates two hormone pathways rather than one.
This dual mechanism may help address some of the metabolic challenges specific to PCOS:
- Reduced appetite and cravings — signals to the brain that you feel fuller
- Improved insulin sensitivity — may help regulate blood sugar and reduce insulin resistance
- Slower gastric emptying — helps you feel satisfied after smaller meals
- Better fat utilisation — supports the body's ability to use stored fat for energy
In clinical trials (SURMOUNT studies), participants taking Mounjaro lost an average of 15–21% of their body weight alongside diet and exercise, though individual results vary significantly. For people with PCOS, weight loss of even 5–10% can improve insulin sensitivity, regulate menstrual cycles, and reduce fertility challenges.
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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
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PCOS, Weight, and Mounjaro Eligibility in the UK
Most adults with PCOS qualify for prescription weight loss treatment in the UK if they have a BMI of 27 kg/m² or above with weight-related health conditions — and PCOS itself is recognised as a condition that increases health risk at lower BMI levels.
Your GP can assess whether a Mounjaro prescription is appropriate based on your individual circumstances, including:
- Your current BMI and health history
- Presence of type 2 diabetes or prediabetes (common with PCOS)
- High blood pressure or abnormal cholesterol
- Previous treatments you've tried
- Other medications you're taking (especially oral contraceptives — these may have reduced effectiveness)
Use our free BMI calculator above to check your current BMI and understand how it relates to treatment eligibility. Access to Mounjaro on the NHS is through specialist tier 3 weight management services, though waiting times vary. Private prescription weight loss UK options are also available following an online 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.
Is Mounjaro safe to take if I have PCOS?
Mounjaro is prescription-only and safety depends on your individual health profile. PCOS itself doesn't prevent Mounjaro use, but your prescriber will review your full medical history, medications (especially hormonal contraceptives), and any complications. Always discuss PCOS-related health concerns with your GP or prescriber before starting treatment.
Will Mounjaro help my irregular periods with PCOS?
Weight loss achieved through Mounjaro may improve hormonal balance and menstrual regularity in PCOS, as insulin resistance is often a key driver. However, Mounjaro is not a PCOS treatment itself — it's a weight management medication. Any menstrual improvements would result from weight loss and improved insulin sensitivity, not directly from the medication.
Can I take Mounjaro if I'm also on the pill for PCOS?
Mounjaro may reduce absorption of oral contraceptives, so you should add a barrier method or switch to a non-oral contraceptive for 4 weeks after starting Mounjaro and 4 weeks after each dose increase. Discuss this with your prescriber before starting, as they can advise on the best approach for your individual situation.
How long does it take to see weight loss results with Mounjaro and PCOS?
Most people begin to notice appetite reduction within days to weeks, but significant weight loss typically takes 8–12 weeks to become apparent. Mounjaro is titrated (doses increased gradually) over 16+ weeks. Individual timelines vary — clinical trials showed average weight loss plateauing around 16–20 weeks at maintenance dose.
What's the difference between Mounjaro and Wegovy for PCOS weight management?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist, whilst Wegovy (semaglutide) is a GLP-1-only agonist. Both are prescription-only weight management injections licensed in the UK. Mounjaro may offer slightly greater weight loss on average, but individual response varies. Your prescriber will recommend the most appropriate option based on your health profile and circumstances.
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.