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
Magnesium Citrate for Weight Loss — Before and After Facts
Magnesium citrate is a supplement that some people use hoping it will help with weight loss, but the evidence for direct weight loss is limited. Magnesium citrate is primarily a laxative — it works by drawing water into the bowel to ease constipation. While it may cause temporary water loss and reduced bloating, it is not a weight loss medication. If you're interested in evidence-based weight management in the UK, prescription options like GLP-1 weight loss injections have much stronger clinical backing. This guide explains what magnesium citrate actually does, why it's not a weight loss solution, and what genuinely effective options exist.
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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 Magnesium Citrate Works and Why It's Not a Weight Loss Drug
Magnesium citrate is a type of magnesium supplement combined with citric acid. Its primary function is as a saline laxative — it works by osmosis, drawing water into the intestines to soften stool and ease bowel movements. This is why it's often used to treat constipation and to prepare for medical procedures like colonoscopies.
When people see "before and after" results claiming magnesium citrate weight loss, what they're usually observing is temporary fluid loss and reduced bloating, not actual fat loss. Once you rehydrate after taking magnesium citrate, the weight returns. This is not sustainable weight loss.
Magnesium does play a genuine role in health — it supports muscle function, energy production, and heart rhythm regulation. Some research suggests adequate magnesium intake may support metabolism, but taking excess magnesium citrate specifically for weight loss is not evidence-based practice. The NHS does not recommend magnesium citrate as a weight management tool.
If you're struggling with weight management in the UK, your GP can discuss options ranging from lifestyle changes and structured diet programmes through to prescription weight loss medication, which has clinical trial evidence behind it.
Clinically BackedWeight Loss
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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
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Evidence-Based Weight Loss Options That Actually Work
If you're genuinely interested in weight management, prescription weight loss injections like Wegovy (semaglutide) and Mounjaro (tirzepatide) have strong clinical evidence. Wegovy clinical trials showed an average weight loss of approximately 15% of body weight, while Mounjaro demonstrated up to 21% in SURMOUNT trials — results achieved alongside a reduced-calorie diet and increased physical activity.
These are prescription-only medications requiring a clinical assessment to check if they're suitable for you. Access in the UK is through NHS specialist weight loss services or private online prescribing. Using our GLP-1 weight loss calculator, you can estimate potential weight loss at different doses and see how prescription medication might support your weight management goals.
Sustainable weight loss typically involves a combination of dietary changes, physical activity, and sometimes medication — never a supplement alone. Your GP or a licensed prescriber can help you find the right approach for your circumstances.
- 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.
Will magnesium citrate make me lose weight permanently?
No. Magnesium citrate causes temporary water loss and may reduce bloating, but once you rehydrate, the weight returns. It is not a weight loss medication and does not burn fat. For sustainable weight loss, you need a calorie deficit through diet and activity, or prescription medication approved for weight management.
Is magnesium citrate the same as magnesium supplements for weight loss?
Magnesium citrate is primarily a laxative, not a general health supplement. While magnesium is essential for health, taking extra magnesium citrate for weight loss is not supported by evidence. Other magnesium forms (like glycinate) support general health but are not weight loss drugs either.
What weight loss medication is actually available on the NHS in the UK?
The NHS offers tirzepatide (Mounjaro) and semaglutide (Wegovy) through specialist tier 3 weight management services for eligible adults. GLP-1 weight loss injections are prescription-only and require assessment by a healthcare professional. Availability and waiting times vary by region.
How much weight can I expect to lose with prescription weight loss medication?
Clinical trials show Wegovy users lost an average of 15% of body weight, while Mounjaro users lost 15–21%. However, individual results vary significantly. These medications work best alongside a reduced-calorie diet and increased physical activity. Use our GLP-1 weight loss calculator to estimate potential outcomes for your situation.
What's the safest rate of weight loss according to the NHS?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable results. This typically requires a calorie deficit of around 500 kcal per day. Faster weight loss increases the risk of muscle loss and nutritional deficiency. Always consult your GP before starting any weight loss programme.
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.