electrolytes

Electrolytes are minerals that carry an electric charge when dissolved in body fluids; in supplements the main ones are sodium, potassium, and magnesium. According to MedlinePlus and the NIH Office of Dietary Supplements (ODS), they help keep your body's water balanced and its acid/base (pH) level steady, and they support normal nerve, muscle, and heart function. Most people get adequate electrolytes from a varied diet, and "electrolyte" products (powders, drinks, tablets) mainly combine these minerals.

Electrolytes are essential nutrients, but evidence that supplementing healthy, well-nourished people produces added health benefits is limited and heavily hedged by the NIH. For potassium, ODS notes that getting more potassium and less sodium "might help lower your blood pressure and reduce your risk of stroke" and "might reduce your risk of developing kidney stones," while for blood sugar and type 2 diabetes "more research is needed." For magnesium, ODS states that supplements "might decrease blood pressure, but only by a small amount," that in diet studies "it's hard to know how much of the effect was due to magnesium" versus other nutrients, and that "more research is needed" for diabetes, osteoporosis, and migraine. MedlinePlus frames electrolytes mainly around correcting imbalance from causes such as dehydration, vomiting, diarrhea, or illness rather than around routine supplementation in healthy people.

There is no single dose for an "electrolyte" product; needs depend on age, sex, diet, and fluid losses. NIH ODS lists average daily recommended amounts of roughly 2,600 mg (women) to 3,400 mg (men) of potassium and about 310–420 mg of magnesium for most adults, intended to come mostly from food. MedlinePlus notes that dietary guidelines recommend most adults eat less than about 2,300 mg of sodium per day. Potassium-only supplements typically provide no more than 99 mg per serving, and magnesium from supplements and medications should not exceed the adult upper limit of 350 mg per day unless a clinician directs otherwise (this limit excludes magnesium naturally present in food). Talk to a clinician or pharmacist before starting electrolyte supplements, especially if you have kidney, heart, or blood-pressure conditions or take prescription medications.

From food and beverages, these minerals are generally not harmful in healthy people with normal kidney function, because the kidneys excrete the excess. Supplements carry more risk: ODS warns that getting too much potassium from supplements or salt substitutes can cause dangerously high blood potassium (hyperkalemia), and that magnesium from supplements or medications above the upper limit can cause problems. People with chronic kidney disease, congestive heart failure, type 1 diabetes, liver disease, or adrenal insufficiency, and those taking certain blood-pressure drugs, can develop hyperkalemia even at typical potassium intakes and should consult a clinician before using potassium supplements or salt substitutes.

High intakes of magnesium from supplements or medications can cause diarrhea, nausea, and abdominal cramping, and ODS notes that extremely high intakes can lead to irregular heartbeat and cardiac arrest. Excess potassium from supplements can cause hyperkalemia (high blood potassium), which can disturb heart rhythm. Excess sodium can raise blood pressure, particularly in people whose kidneys cannot clear the excess.

Potassium can interact with ACE inhibitors (e.g., benazepril) and angiotensin receptor blockers (e.g., losartan), and with potassium-sparing diuretics, all of which can raise blood potassium to unsafe levels. Magnesium supplements can interfere with bisphosphonates (osteoporosis drugs) and with certain antibiotics when taken too close together, and some diuretics can change how much magnesium the body keeps or loses. Because of these interactions, ODS advises talking with your health care provider or pharmacist about whether electrolyte supplements are right for you.