Supplement Guide | Electrolytes 01 | The $45 Billion Business Built on a Deficiency Most People Don't Have
This is part 1 of SuppCo's 3-part Supplement Guide on electrolytes. The series covers what electrolytes actually do in the body and why the market around them exploded, the research on when they actually matter for athletic performance, and a practical guide to what to look for when you buy one.
Forty-five billion dollars. That's what market research estimates the global electrolyte drink market is worth this year, on pace to reach seventy-eight billion by 2035. Meanwhile the average American adult already eats more than 3,300 milligrams of sodium a day, per the CDC's current intake data, against a recommended ceiling of 2,300 milligrams. We are already eating past that sodium ceiling and, somehow, also the target market for a growing list of products designed to add more.
Sodium does matter (so do the other electrolytes). What the supplement industry rarely explains is what they do in the body, and who needs them. This article covers both, starting with what the five core electrolytes actually do.
What "Electrolyte" Means
Simply put, an electrolyte is a mineral that carries an electrical charge when it's dissolved in water. Sodium, potassium, chloride, magnesium, and calcium carry the biggest share of that work in the human body, and each one holds a different charge in a different compartment. Sodium stays concentrated in the fluid outside your cells. Potassium stays concentrated inside them. A membrane pump called the sodium-potassium ATPase spends a steady stream of cellular energy keeping that gradient in place, and that gradient is what lets a nerve fire and a muscle contract.
Water follows these minerals, and the clearest proof is in the gut. A transporter called SGLT1 pulls two sodium ions and one glucose molecule across the intestinal wall together, and water follows that pull by osmosis into the bloodstream. Without that sodium-glucose gradient, water crosses far more slowly on its own. That mechanism is the basis for the WHO's oral rehydration solution, the formula used worldwide to treat severe dehydration: a precise mix of sodium, glucose, potassium, and citrate built around exactly this concept.
The Body's Built-In Thermostat
Serum sodium sits in a narrow band, roughly 135 to 145 mmol per liter, and the kidneys defend that range aggressively. When blood volume or blood pressure drops, which happens as sodium and the water that follows it get lost, the kidneys release an enzyme called renin. That kicks off a hormone chain reaction, the renin-angiotensin-aldosterone system, ending with the adrenal glands releasing aldosterone, which tells the kidneys to reabsorb more sodium instead of removing it. When the blood's overall solute concentration climbs too high, the pituitary gland releases antidiuretic hormone, which tells the kidneys to hold onto water instead.
The two systems work against each other constantly, adjusting by the hour, to keep that 135–145 window intact regardless of what's on your plate or in your water bottle.
That regulation is why extra dietary sodium doesn't accumulate in someone with normal kidney function. Eat more than the body needs and the kidneys excrete the surplus, usually within a day, without waiting for thirst or fatigue to signal it first.
Someone already consuming 1,000 milligrams more sodium than they need is somehow still the target market for adding more.
What About Other Electrolytes?
Sodium gets the attention, but potassium, magnesium, calcium, and chloride are part of this conversation too, and the picture is different for each. About 48% of Americans consume less magnesium than the Estimated Average Requirement, the level that meets the needs of half of healthy people in a given group, according to a USDA analysis of NHANES data. Potassium intake runs low too: the average man eats 3,016mg a day against a 3,400mg target, the average woman 2,320mg against 2,600mg.
Eating below a target isn't the same as being deficient. Measured blood-level magnesium deficiency is estimated at 2.5% to 15% of the general population, depending on the population and screening method, and severe hypokalemia is rare in people with normal kidney function, according to the clinical literature. True deficiency in either mineral concentrates in specific groups instead: people with alcohol use disorder, where magnesium deficiency runs close to 30%, along with poorly controlled type 2 diabetes, GI conditions that can interfere with absorption like Crohn's or celiac disease, and anyone on diuretics that flush minerals out through the kidneys.
Calcium and chloride follow a similar split. Blood calcium is regulated tightly enough by parathyroid hormone and vitamin D that a shortfall usually points to one of those systems malfunctioning (not necessarily a diet gap). Chloride mostly moves with sodium too, in everyday diet and sweat losses, but vomiting is the exception: it strips chloride specifically, from stomach acid, faster than it strips sodium, which is why chloride can fall further than sodium does during a bad stomach bug.
Why This Became a Billion-Dollar Habit
GLP-1 medications get blamed for part of the electrolyte boom, on the theory that eating less food means also eating less sodium. A 2019 reanalysis of two small clinical trials found a mixed picture instead. Intravenous exenatide (a GLP-1 receptor agonist) cut sodium intake by up to 30% compared to placebo, but only because it suppressed appetite generally, not sodium specifically. Three months of liraglutide, compared against insulin therapy rather than a placebo, produced no change in sodium intake at all.
Sodium was never the primary outcome either trial was designed to test, and the researchers called for dedicated studies before drawing firm conclusions. A 2025 study of real-world GLP-1 users found the same pattern playing out: average sodium intake still ran about 40% above the recommended limit.
After GLP-1s, add a booming wellness culture that widened "hydration" from a locker-room concept into an everyday habit, and a supplement built for marathoners ends up stocked in the corporate breakroom. Liquid I.V., acquired by Unilever in 2020, is on track to become a $1 billion brand inside that company. Its CEO has said the growth came from recognizing that hydration "is just not for athletes." Powdered hydration mixes as a category grew 20% in 2024 alone, reaching $1.5 billion, and similar products are now sold across retail locations all over the United States.
Who Actually Has a Gap
Some situations create a real, measurable electrolyte deficit. Heavy or prolonged sweating is the obvious one, and Part 2 of this series covers exactly how much that varies person to person. Vomiting or diarrhea can strip sodium and potassium fast enough to cause symptoms within a day. Older adults on diuretic medication lose more sodium and potassium through the kidneys by design, since that's how the drug works.
Outside of those situations, the average sedentary adult eating a normal mixed diet isn't walking around with a sodium shortfall. Current CDC intake data puts the typical adult roughly 1,000 milligrams over the recommended daily ceiling, not under it, and a 2021 CDC analysis of NHANES data found that ~88% of adults exceeded the limit in every single survey cycle measured, with no meaningful improvement over 13 years.
A product… correcting a deficiency that isn't there… isn't doing you any favors.
Where to check yourself:
Heavy or salty sweat, training sessions that leave visible white marks on dark clothing or skin
Training sessions that regularly run past 60 to 90 minutes, especially in heat
Vomiting, diarrhea, or another illness causing fluid loss over more than a day
Diuretic medication, prescribed for blood pressure or fluid retention
Most of these (likely) do not apply to us on a daily basis, and diet alone is very likely covering what your body needs already.
Sodium, potassium, and the rest genuinely run the electrical and fluid systems that keep a body upright. But it is important to understand if that formula is solving something for the person drinking it, or trying to address an issue their kidneys already handled hours ago.
Real physical exertion is the one place that calculation reliably changes, and even there it isn't as simple as sweat equals salt. Part 2 covers when electrolyte needs during exercise are real, how much they vary from one athlete to the next, and why the runners drinking the most water aren't always the safest ones on the course.