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
Women's Vitamins for Weight Loss — What Actually Works in the UK
While vitamins and supplements are often marketed for weight loss, the evidence for their effectiveness is limited. If you're looking for clinically proven support for weight management in the UK, prescription medications like Mounjaro and Wegovy offer significantly stronger evidence. This guide explains what the research shows about supplements, and how to access evidence-based weight loss medication if you're eligible. Use our free BMI calculator above to check where you stand, and discover what options might be right for you.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
UK-Licensed Prescription Weight Loss Medication for Women
For women seeking effective weight management support, prescription medications are more evidence-based than vitamins or supplements. Three options are currently licensed in the UK:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 pathways. Clinical trials showed women lost an average of 15–21% of body weight alongside diet and exercise changes.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Women in trials lost approximately 15% of body weight on average at the maximum dose.
- Saxenda (liraglutide) — a daily GLP-1 injection, offering an alternative for those preferring daily administration.
All three are prescription-only and require a clinical assessment to confirm eligibility. Individual results vary significantly, and these medications are most effective when combined with reduced-calorie diet and increased physical activity.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
NHS Access vs Private Prescribing — How to Get Started
NHS route: Weight loss medications are available through specialist tier 3 weight management services, typically accessed via GP referral. Availability and waiting times vary significantly by region and NHS integrated care board (ICB). Some areas have long waiting lists.
Private route: GPhC-registered online pharmacies offer prescription weight loss medication following an online clinical assessment with a UK-licensed prescriber. This route is faster but comes at a cost, typically £129–£320 per month depending on dose.
Start by discussing your weight and health goals with your GP, who can assess your BMI and eligibility. Use our free weight loss calculator to explore potential outcomes at different doses, and track your progress with our progress tracker once you begin treatment.
- 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.
Are vitamins and supplements effective for weight loss?
Limited scientific evidence supports weight loss vitamins or supplements for significant, sustained weight loss. Most herbal and vitamin supplements lack strong clinical trials in humans. Prescription medications like Mounjaro and Wegovy have robust clinical evidence showing 15–21% average body weight loss.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or BMI 27–29.9 with a weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea), may be eligible. South Asian, Chinese, Black African, and Black Caribbean women may qualify at lower BMI thresholds due to higher health risks at lower weights.
How long does it take to see results with Mounjaro or Wegovy?
Most people notice appetite changes within the first few weeks. Measurable weight loss typically becomes apparent within 4–8 weeks of treatment. Maximum effects are usually seen after 16–20 weeks at a stable dose. Individual timelines vary significantly.
Can I get weight loss injections through the NHS?
Yes, GLP-1 and GIP/GLP-1 medications are available through NHS specialist weight management services (tier 3), but access varies by region and waiting times can be lengthy. Private prescription through online services is typically faster, though not available on the NHS.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) activates two hormone pathways (GIP and GLP-1), while Wegovy (semaglutide) activates one pathway (GLP-1 only). Clinical trials suggest Mounjaro may produce slightly greater average weight loss (up to 21% vs 15%), but individual results vary. Both are once-weekly injections.
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.