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 Do Electrolytes Do For Weight Loss?
Electrolytes are minerals that regulate vital body functions including hydration, muscle function, and nerve signalling — but they don't directly cause weight loss. However, they become important during weight management and when taking prescription weight loss injections like Wegovy or Mounjaro. Understanding electrolyte balance helps protect your health during dieting and supports the effectiveness of weight loss medication nhs services may recommend. This guide explains what electrolytes actually do and why they matter for safe, sustainable weight loss in the UK.
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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 Electrolytes Support Your Body During Weight Loss
Electrolytes (sodium, potassium, magnesium, and calcium) are minerals that carry electrical charges in your body. They regulate muscle contractions, nerve signals, heart rhythm, and hydration levels. During weight loss, especially with prescription weight loss uk injections, electrolyte balance becomes crucial because:
- Reduced food intake means fewer electrolytes from diet
- GLP-1 medications like Wegovy slow gastric emptying, affecting nutrient absorption
- Dehydration risk increases during weight loss, concentrating electrolytes
- Low electrolyte levels can cause muscle weakness, cramps, fatigue, and dizziness
- Proper electrolyte balance supports healthy metabolism and energy levels
You don't need special electrolyte supplements if you eat balanced meals with plenty of vegetables, fruits, nuts, and lean proteins. However, if you're experiencing symptoms like muscle cramps or persistent fatigue during weight management, your GP can assess whether you need electrolyte support.
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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.
Electrolytes and GLP-1 Weight Loss Medication
If you're taking glp-1 weight loss injections like Wegovy or Mounjaro, electrolyte management is part of staying healthy. These medications slow digestion and reduce appetite, which can lead to lower food intake overall — meaning fewer electrolytes consumed. Additionally, some people experience mild dehydration as a side effect, which can affect electrolyte balance.
To maintain healthy electrolyte levels during weight loss injections: drink plenty of water (not just sugary drinks), eat electrolyte-rich foods like leafy greens, sweet potatoes, bananas, and nuts, and avoid excessive salt restriction unless your GP advises otherwise. Track your progress using our free progress tracker to monitor how you feel alongside weight changes. If you experience persistent fatigue, muscle cramps, or irregular heartbeat, contact your GP immediately — these can signal electrolyte imbalance.
- 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.
Do electrolytes help you lose weight directly?
No. Electrolytes don't burn fat or cause weight loss themselves. However, they're essential for your body to function properly during weight loss. Proper electrolyte balance supports energy, muscle function, and metabolism — all important for sustainable weight management. Weight loss comes from calorie deficit, not electrolytes. Use our free BMI calculator to understand your weight management goals.
What electrolytes do I need during weight loss?
The main electrolytes are sodium, potassium, magnesium, and calcium. Most people get enough from a balanced diet of vegetables, fruits, nuts, lean proteins, and whole grains. You don't typically need supplements unless your GP identifies a deficiency. During prescription weight loss treatment, maintain normal electrolyte intake through food rather than excess salt.
Can electrolyte drinks help with weight loss injections?
Standard electrolyte drinks often contain added sugar and calories, which can interfere with weight loss. Plain water is usually the best choice. If you're concerned about electrolyte balance while taking Wegovy or Mounjaro, discuss this with your prescriber or GP — they can recommend appropriate options without added sugars.
What are signs of low electrolytes during weight loss?
Symptoms include muscle cramps, weakness, fatigue, dizziness, headaches, and irregular heartbeat. If you experience these while dieting or taking weight loss injections, contact your GP. Don't self-treat with supplements without professional guidance — your GP can assess your individual needs and electrolyte levels if necessary.
Should I take electrolyte supplements with Wegovy or Mounjaro?
Most people don't need electrolyte supplements if eating a varied, balanced diet. However, if you're experiencing side effects like persistent nausea or very low food intake, discuss this with your prescriber. They can assess whether supplementation is needed for your situation and recommend appropriate options.
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.