What Electrolytes Do: Sodium, Potassium, Calcium, Magnesium, Chloride and Phosphate
A plain-language guide to what sodium, potassium, calcium, magnesium, chloride and phosphate do in the body, how they are measured, and where each one comes from.
Content last updated . This page has not been medically reviewed.
Quick answer
Electrolytes are minerals in your blood and other body fluids that carry an electric charge. [1] They affect and are affected by the amount of water in your body, the acidity of your blood, and how your nerves and muscles work. [1] MedlinePlus lists the common ones as calcium, chloride, magnesium, phosphorus, potassium and sodium. [1] Bicarbonate is also counted among the main electrolytes. [2] This page explains the jobs in everyday words. It is information only and does not tell anyone what to take.
What they do together
MedlinePlus says electrolytes help to balance the amount of water in your body and your acid/base (pH) level, move nutrients into cells and wastes out, support muscle and nerve function, keep heart rate and rhythm steady, keep blood pressure stable, and keep bones and teeth healthy. [2] Several of these jobs depend on more than one electrolyte working together, which is why a problem with one can show up alongside a problem with another.Each electrolyte at a glance
| Electrolyte | What the source says it helps with | Where the full guide is |
|---|---|---|
| Sodium | Helps control the amount of fluid in the body and helps nerves and muscles work. [2] | More about Sodium → |
| Potassium | Helps cells, heart and muscles work properly. [2] | More about Potassium → |
| Chloride | Helps control the amount of fluid in the body. [2] | More about Chloride → |
| Calcium | Helps make and keep bones and teeth strong. [2] | More about Calcium → |
| Magnesium | Helps muscles, nerves and heart work properly. [2] | More about Magnesium → |
| Phosphate | Works together with calcium to build strong bones and teeth. [2] | More about Phosphate → |
| Bicarbonate | Helps maintain the body's acid and base balance (pH). [2] | Not a supplement topic in this library |
Where they come from
You get these electrolytes from the foods you eat and the fluids you drink. [2] Water alone does not contain a significant amount of them. [1] Sodium, for example, occurs naturally in most foods and is added to many processed ones. [3] MedlinePlus puts total water needs for US adults at 2.7 to 3.7 liters a day from food and drink together, and notes that individual needs vary with sex, weight, age, activity and medical conditions. [4]How electrolytes are measured
Each electrolyte can be measured separately in blood, and sodium, potassium, chloride and calcium can also be measured as part of a basic metabolic panel. [1] A basic metabolic panel is also called an electrolyte panel or chem 7. [5] A separate urine test can measure electrolytes in urine. [1] Results are read together with symptoms and other tests, and a result outside the usual range does not always mean a condition that needs treatment. [6] Lab ranges differ slightly between laboratories, so only a clinician can say what a result means for one person.Why "more" is not better
Balance matters in both directions. An imbalance means the level of one or more electrolytes is too low or too high. [2] Each has its own risks when taken in extra amounts as a supplement, which is why the profile pages exist. For example, eating very large amounts of potassium-rich foods or taking potassium supplements can lead to health problems. [7] Kidney, heart and liver conditions and some medicines change how the body handles electrolytes. [2] Check with a clinician or pharmacist before adding electrolyte products, and see Medication interactions.Where this fits
- If you are looking for what to do about vomiting or diarrhea, go to Oral rehydration solutions.
- If you are asking whether you have a problem, go to Electrolyte imbalance: symptoms and when to seek care.
- For the overview, see Electrolytes and electrolyte supplements.
Frequently asked questions
What are the main electrolytes?
MedlinePlus lists calcium, chloride, magnesium, phosphorus, potassium and sodium, and elsewhere also names bicarbonate. [1][2]
Are minerals and electrolytes the same thing?
MedlinePlus defines electrolytes as minerals with an electric charge in body fluids. [1] Other minerals in this library, such as iron or zinc, are not on its list of common electrolytes, so the two words overlap but are not identical.
Do electrolytes give you energy?
Electrolytes support nerve and muscle function and fluid balance. [2] Proper evidence not found in the sources we read that electrolytes themselves provide energy; claims to that effect are marketing claims.
How do I know if my electrolytes are off?
A blood test such as an electrolyte panel checks the main ones. [2] Symptoms alone are not a reliable guide, so talk to a clinician.
Can food provide enough?
You get electrolytes from food and drink. [2] Amounts and needs vary by person, so ask a clinician if you have a medical condition.
References
- MedlinePlus Medical Encyclopedia, Electrolytes (review date 10/1/2025). Read 2026-10-22.
- MedlinePlus, Fluid and Electrolyte Balance. Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Sodium in diet (review date 4/30/2026). Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Water in diet (review date 7/9/2025). Read 2026-10-22.
- MedlinePlus Medical Tests, Basic Metabolic Panel (BMP). Read 2026-10-22.
- MedlinePlus Medical Tests, Sodium Blood Test. Read 2026-10-22.
- MedlinePlus Medical Tests, Potassium Blood Test. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.