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
What is Manjiro? UK Guide to Semaglutide & Weight Management
Manjiro isn't an official medication name, but it may refer to semaglutide — a GLP-1 injection licensed for weight management in the UK under the brand name Wegovy. This guide explains how semaglutide works, who it's suitable for, and how it compares to other weight management options. Whether you're exploring NHS health guidance or researching weight management approaches, understanding the facts about GLP-1 medications helps you make informed decisions. Use our free BMI calculator to assess your current health status, and our GLP-1 weight loss calculator to understand potential outcomes with treatment.
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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 Semaglutide Works & What Wegovy Does
Semaglutide is a GLP-1 receptor agonist — a prescription-only injection that mimics the natural GLP-1 hormone your gut produces after eating. In the UK, semaglutide is licensed for weight management under the brand name Wegovy (doses up to 2.4 mg once weekly).
It works by:
- Reducing appetite and food cravings
- Helping you feel fuller after smaller meals
- Slowing how quickly food leaves your stomach
- Supporting better blood sugar control
In clinical trials (STEP-1), semaglutide helped participants lose an average of approximately 15% of their body weight over 68 weeks — though individual results vary significantly. Semaglutide is not insulin and does not work the same way.
Important distinction: Ozempic also contains semaglutide but is approved for type 2 diabetes management only. Wegovy is the licensed UK brand for weight management and is what's prescribed for weight loss.
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.
UK Eligibility & How to Access Semaglutide
In the UK, adults may be eligible for semaglutide (Wegovy) if they have a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Use our BMI calculator to check your status — for South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply due to higher health risks at lower BMI levels.
You can access semaglutide through two routes: referral to an NHS specialist weight management service (though waiting lists vary by region and availability is limited), or via a private consultation with a UK-licensed prescriber. Both routes require a clinical assessment. Side effects are common in early weeks — nausea, diarrhoea, and stomach pain — but often improve as your body adjusts. Your prescriber will discuss risks and monitor your progress.
- 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 manjiro the same as semaglutide or Wegovy?
Manjiro isn't an official medication name. You may be thinking of semaglutide, which is sold as Wegovy for weight management in the UK. Both terms refer to the same active ingredient — a GLP-1 injection. Always use the brand name Wegovy when discussing it with your GP or prescriber.
Is semaglutide (Wegovy) available on the NHS in the UK?
Yes, semaglutide is available on the NHS through specialist tier 3 weight management services, but access is limited and regional. You can also access it privately through a UK-licensed prescriber without an NHS referral. Both routes require a clinical assessment and prescription.
How much weight can you lose with semaglutide?
In clinical trials, semaglutide helped people lose an average of 15% of body weight over 68 weeks — roughly 1–2 kg per week initially. However, individual results vary significantly and depend on dose, lifestyle changes, and personal factors. Your actual outcome may differ.
What's the difference between semaglutide and tirzepatide (Mounjaro)?
Semaglutide (Wegovy) is a GLP-1 agonist. Tirzepatide (Mounjaro) is a dual GIP and GLP-1 agonist — it activates two hormone pathways instead of one. Clinical trials show tirzepatide may produce slightly higher average weight loss, but both are effective. Your prescriber will recommend which suits you.
Is semaglutide safe? What are the side effects?
Semaglutide is safe when prescribed appropriately, but side effects are common — especially nausea, diarrhoea, constipation, and stomach pain in the first few weeks. These usually improve as your body adjusts. Serious side effects are rare. Always discuss risks with your prescriber and report any severe symptoms.
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.