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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PCOS Weight Loss Medication in the UK
Weight management is an important part of managing polycystic ovary syndrome (PCOS), and several prescription medications are now available in the UK that may help. GLP-1 receptor agonist medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) have shown evidence of supporting weight loss, which can improve insulin resistance and PCOS symptoms. This guide explains how these medications work, UK eligibility, and how to access them through the NHS or private prescribing.
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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 GLP-1 Medications May Help with PCOS
GLP-1 receptor agonist medications mimic a natural hormone that helps regulate appetite and blood sugar. For people with PCOS, this mechanism may be particularly beneficial because many with PCOS have insulin resistance — a condition where the body doesn't respond properly to insulin, leading to weight gain and worsening symptoms.
In clinical trials, Wegovy (semaglutide) helped participants lose an average of approximately 15% of body weight over 68 weeks, whilst Mounjaro (tirzepatide) — which works on two hormone pathways — showed average weight loss of 15–21% in the SURMOUNT trials. These medications are prescription-only and require a clinical assessment before being prescribed. Weight loss achieved through medication is typically more effective when combined with reduced-calorie diet and increased physical activity.
Use our free GLP-1 weight loss calculator to estimate potential weight loss outcomes at different doses, and our BMI calculator to check your starting point.
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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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UK Access to PCOS Weight Loss Medication
In the UK, prescription weight loss medication may be available through two routes: NHS specialist weight management services and private online prescribing.
NHS access: You can ask your GP for a referral to your local tier 3 specialist weight management service. NICE has approved both tirzepatide (Mounjaro) and semaglutide (Wegovy) for use within NHS specialist services. However, availability varies significantly by region, and waiting times can be several months to over a year in some areas.
Private access: GLP-1 medications are available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. This route does not require an NHS referral. Always verify the pharmacy is registered with the General Pharmaceutical Council before ordering.
Track your weight loss journey using our free progress tracker.
- 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 Wegovy or Mounjaro better for PCOS weight loss?
Both medications may help with PCOS-related weight loss. Wegovy (semaglutide) is a GLP-1 agonist with strong trial evidence. Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist that showed higher average weight loss in trials (~20% vs ~15%). Individual results vary significantly. A prescriber can assess which is more suitable for your health profile. Either medication is prescription-only and requires clinical assessment.
How quickly will I lose weight on these medications?
Weight loss happens gradually. Most people see results within 4–6 weeks of starting, with progressive loss over 12–16 weeks as the dose increases. Average weekly loss is approximately 0.5–1 kg, but this varies. Clinical trials measured weight loss over 68–72 weeks. Sustainable weight loss is typically 0.5–1 kg per week. Results depend on individual metabolism, diet, and physical activity alongside the medication.
Can I get weight loss medication on the NHS for PCOS?
Yes, if you meet eligibility criteria. You need a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions (PCOS may qualify). Ask your GP for a referral to your local tier 3 specialist weight management service. Availability and waiting times vary by region. Some ICBs have longer waits than others. Your GP can check local pathways.
What are the main side effects of GLP-1 medications?
Common side effects include nausea, diarrhoea, constipation, and stomach pain — usually mild and temporary. Most people tolerate these well. Serious side effects are rare but may include severe stomach pain (possible pancreatitis) or gallbladder problems. Always report persistent symptoms to your prescriber. Side effects often reduce over time as your body adjusts.
Do I need to stay on the medication forever?
Not necessarily. Some people maintain weight loss after stopping, especially if they've changed eating habits and activity levels. Others regain weight when stopping medication. This varies individually. Your prescriber will discuss a long-term plan with you. For PCOS specifically, weight management is ongoing, and medication is one tool alongside diet and lifestyle changes.
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.