Electrolytes and Electrolyte Supplements: What They Are and When They Matter
What electrolytes are, when illness or heavy sweating makes them matter, what the sources say about electrolyte powders, and why extra sodium, potassium or water can backfire.
Content last updated . This page has not been medically reviewed.
Quick answer
Electrolytes are minerals that carry an electric charge when they are dissolved in blood and other body fluids. [1] Most healthy people get what they need from food and drink. [2] Extra electrolytes matter mainly when a lot of fluid is lost, for example in vomiting, diarrhea or heavy sweating, and in those cases the sources point to oral rehydration solutions or a clinician, not a daily wellness powder. [3] This page is information only. It does not replace advice from a clinician or pharmacist.
Urgent first. Severe dehydration is a life-threatening emergency. [4] In the US, call 911 for someone who loses consciousness, is confused or has a seizure. [4] For a child who has swallowed a supplement, call Poison Help at 1-800-222-1222.
What electrolytes are
The main ones are sodium, potassium, chloride, calcium, magnesium, phosphate and bicarbonate. [2] They help balance the water in your body, support muscles and nerves, keep the heartbeat steady and keep blood pressure stable. [2] Water alone does not contain a significant amount of them, and you lose some when you sweat. [1] For a plain-language tour of each one, see What electrolytes do.When balance can go wrong
An imbalance means one or more electrolytes is too low or too high. [2] Common reasons include certain medicines, severe vomiting or diarrhea, heavy sweating, heart, liver or kidney problems, and drinking too much water. [2] Treatment depends on which electrolyte is off and why. [2] An electrolyte panel, which is a blood test, checks the levels of the main electrolytes. [2] Only a clinician can interpret it. See Electrolyte imbalance: symptoms and when to seek care.Evidence labels used on this page
We use plain labels: established role or treatment (documented in official or clinical sources), evidence in healthy people (trials in people who are not ill), and Proper evidence not found (we looked and found nothing usable).| Situation | What the sources say | Label |
|---|---|---|
| Vomiting or diarrhea | The NHS says to replace lost sugar, salts and minerals, and that a pharmacist can recommend oral rehydration powders. [3] | Established treatment |
| Heavy sweating in sport | MedlinePlus mentions sports drinks with electrolytes for vigorous activity. [5] Reviews of endurance events describe drinking to thirst without extra sodium. [6] | Mixed; see the exercise hyponatremia page |
| Daily powders or tablets in healthy people | Proper evidence not found in the sources below. | Not established |
Electrolyte powders in everyday life
We searched PubMed for trials and reviews of electrolyte supplementation in healthy adults, sodium supplementation and cramps, and electrolyte drinks and blood pressure, and read MedlinePlus and NHS pages on rehydration. Proper evidence not found to support routine daily powders or tablets in people who are not ill or training hard. Claims of "energy", "detox" or "all-day hydration" are marketing claims. The full claim check is on Electrolyte powders, drinks and tablets.What to look for on a label:
- Sodium. Healthy US adults are advised to limit sodium to 2,300 mg a day, and adults with high blood pressure to 1,500 mg. [7] The Daily Value on US labels is 2,300 mg, and 20% DV or more per serving is considered high. [8]
- Potassium. Eating very large amounts of potassium-rich foods or taking potassium supplements can cause health problems. [9]
- Magnesium and calcium have their own limits as supplements; see Magnesium and Calcium.
- Salt tablets. MedlinePlus says not to take them for dehydration because they can cause serious complications. [4]
Water and electrolytes together
Overdrinking can dilute blood sodium. A review says drinking according to thirst is the most individualized way to prevent dangerous low sodium during exercise. [10] MedlinePlus puts total water needs for US adults at 2.7 to 3.7 liters a day from food and drink together, and says individual needs vary. [11]Who should be careful
- People with kidney disease, heart failure or cirrhosis, who may need to limit sodium even more than other adults. [7]
- People taking diuretics, which can lower blood sodium [5], or other medicines; certain medicines and supplements can raise potassium. [9] Ask a pharmacist, and see Medication interactions.
- Children under 5 and older adults, who have a higher risk of dehydration. [3] See Electrolytes for children and infants.
- Anyone pregnant, breastfeeding or planning surgery: no source we read gives electrolyte-product advice for these groups, so ask a clinician.
Related: Sodium and chloride, Potassium, Minerals and kidney disease and Quality testing and certifications.
Frequently asked questions
Do I need electrolytes every day?
Most healthy people get them from food and drink. [2] We found no trial evidence for routine daily powders in healthy people (Proper evidence not found).
What helps with diarrhea or vomiting?
The NHS says a pharmacist can recommend oral rehydration solutions, which are powders mixed with water. [3]
Can you drink too much water?
Yes. Excessive fluid intake is one of the factors behind exercise-associated low blood sodium. [12]
Are salt tablets a good idea?
MedlinePlus says not to take salt tablets for dehydration. [4]
What is low blood sodium?
Hyponatremia is a blood sodium below the normal range of 136 to 144 mEq/L, though lab ranges vary slightly. [5]
References
- MedlinePlus Medical Encyclopedia, Electrolytes (review date 10/1/2025). Read 2026-10-22.
- MedlinePlus, Fluid and Electrolyte Balance. Read 2026-10-22.
- NHS (UK), Dehydration (page last reviewed 1 May 2026). Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Dehydration. Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Low blood sodium (review date 5/19/2025). Read 2026-10-22.
- Review, Proper hydration during ultra-endurance activities, 2019. Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Sodium in diet (review date 4/30/2026). Read 2026-10-22.
- FDA (US), Daily Value on the Nutrition and Supplement Facts Labels. Read 2026-10-22.
- MedlinePlus Medical Tests, Potassium Blood Test. Read 2026-10-22.
- Review, Exercise-Associated Hyponatremia, Frontiers of Hormone Research, 2019. Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Water in diet (review date 7/9/2025). Read 2026-10-22.
- Review, Pathophysiology and treatment of exercise-associated hyponatremia, Journal of Endocrinological Investigation, 2026. 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.