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 Magnesium Glycinate Help with Weight Loss in the UK?
Magnesium glycinate is a supplement that some people take for general health, but it's not a weight loss medication. If you're looking for effective weight management in the UK, prescription options are available for eligible adults. This guide explains the difference between supplements and clinically proven weight loss treatment, and how to find out if you qualify for NHS or private prescription weight management options.
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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.
UK-Licensed Prescription Weight Loss Options
If you're interested in weight management in the UK, the most effective evidence-based options are prescription weight loss medications. Three main options are currently licensed:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist injection, once weekly
- Wegovy (semaglutide) — a GLP-1 receptor agonist injection, once weekly
- Saxenda (liraglutide) — a GLP-1 receptor agonist injection, once daily
In clinical trials, these prescription weight loss medications helped participants lose an average of 15–21% of their body weight when combined with a reduced-calorie diet and increased physical activity. Individual results vary significantly. These are prescription-only medicines requiring a clinical assessment before being prescribed. You can check your eligibility using our free BMI calculator and GLP-1 weight loss calculator on this page.
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 Weight Loss Treatment
In the UK, prescription weight loss medication can be accessed through two routes:
- NHS access: Through specialist tier 3 weight management services. You'll need a GP referral. Availability and waiting times vary significantly by region.
- Private access: Through a UK-licensed prescriber and GPhC-registered pharmacy following an online clinical assessment. No NHS referral needed.
To find out if you're eligible, you'll need a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Start a conversation with your GP about weight management options available to you.
- 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 magnesium glycinate an approved weight loss treatment in the UK?
No. Magnesium glycinate is a dietary supplement, not a licensed weight loss medication. It may support general health, but there is no clinical evidence it causes weight loss. If you're seeking evidence-based weight management, ask your GP about prescription options like Mounjaro or Wegovy.
What are the NHS weight loss medications available in the UK?
The NHS provides access to Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide) through specialist weight management services. These are GLP-1 and GIP/GLP-1 receptor agonists. You need a GP referral and meet specific BMI and health criteria. Regional availability varies.
How much weight can I expect to lose with prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight with Mounjaro or Wegovy, though results vary between individuals. Actual outcomes depend on your starting weight, dose, diet, activity level, and personal metabolism. Your GP or prescriber can discuss realistic expectations.
How do I know if I'm eligible for weight loss medication in the UK?
Use the free BMI calculator on this page to check your BMI. You may be eligible if your BMI is 30 or above, or 27 or above with a weight-related health condition such as type 2 diabetes or high blood pressure. Speak to your GP for a formal assessment.
Can I get prescription weight loss injections on the NHS?
Yes, through a referral to a specialist weight management service. Availability depends on your local NHS integrated care board. Waiting times can be long in many areas. Private prescription options are also available without an NHS referral.
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.