Do electrolyte packets like LMNT and Liquid IV actually work?

Partly. The sodium in packets like LMNT and Liquid IV genuinely matters for people sweating heavily for over an hour, in heat, or during endurance exercise. For a normal day of sitting, walking and a short gym session, sports dietitians say plain water is doing the same job the evidence actually supports.

What's actually in these packets

LMNT packets carry about 1,000 mg of sodium, 200 mg of potassium and 60 mg of magnesium, with no added sugar. Liquid IV's original formula takes a different approach: sugar is its first listed ingredient, and it carries roughly half LMNT's sodium with no magnesium at all. Neither is inherently better. One is built around a high sodium dose for heavy sweat loss, the other around a sugar-assisted absorption model that sports science supports mainly for intense, hour-plus efforts.

The sodium case, and where it comes from

"Sodium is the primary mineral lost in sweat during exercise," says Kelly Pritchett, a board-certified sports dietitian at Central Washington University and spokesperson for the Academy of Nutrition and Dietetics. That's the real mechanism behind these products: sweat isn't just water, and replacing only the water while ignoring the sodium can actually make things worse during long efforts.

A 2016 study in the Scandinavian Journal of Medicine & Science in Sports, run on triathletes, found a clear, measurable effect. Athletes who added salt tablets to their sports drinks replaced about 71% of the sodium they lost through sweat. Athletes who relied on sports drinks alone replaced only about 20%, and the salt-tablet group finished the race roughly 26 minutes faster. [[INLINE]] That's a meaningful real-world result, not a marketing claim, but notice the population: triathletes, in a multi-hour race, in conditions guaranteed to produce heavy sweat loss.

Where the evidence runs out

"In general, water is only recommended for exercise that lasts up to an hour," says Joy Dubost, a New York City-based board-certified sports dietitian. Below that threshold, sweat losses are small enough that a typical diet already covers the sodium, and there's no research showing an electrolyte packet outperforms water for a 30-minute run or a standard strength session.

That matters because most of these products are marketed and consumed well outside the conditions where the evidence applies: a packet stirred into a desk-side water bottle, a "just in case" scoop before a short walk, a daily habit unrelated to sweat rate at all. In that context, you're mostly paying for salt you'd otherwise get from food, and for people managing blood pressure, that extra sodium load is worth noticing rather than ignoring.

Who actually benefits, and the real warning sign

The clearest beneficiaries are endurance athletes, people who exercise hard for over an hour, heavy or "salty" sweaters (a chalky residue on skin or clothes after a hard session is the practical tell), people working outdoors in heat, and anyone who gets muscle cramps, fatigue, nausea or headaches during long exercise. One review of LMNT's own marketing also flags people eating mostly whole, unprocessed foods, which tend to be naturally lower in sodium than packaged food, along with breastfeeding mothers and people with physically demanding jobs as groups more likely to be running a real deficit rather than a perceived one.

There's a real medical risk on the other side too: drinking large amounts of plain water during long, intense exercise without replacing sodium can dilute blood sodium levels into hyponatremia, which in severe cases is dangerous. That risk is specific to endurance-length efforts, not an argument for daily electrolyte packets at your desk. Sports dietitian Marie Spano's practical workaround for anyone unsure which product to buy is simpler than any branded packet: add a pinch of table salt to 8oz of whatever sports drink you're already using before a hard sweat session.

The other side: can you get too much sodium from these

The flip side rarely makes it into the marketing. Sedentary people, or anyone already eating a typical sodium-heavy processed diet, risk adding electrolyte-packet sodium on top of an intake that's already at or above recommended levels. That's a different conversation than the hydration one, and it matters most for people managing high blood pressure or kidney disease, who should treat a daily sodium-forward packet as a medical question, not a wellness habit, and loop in a doctor before making it routine. Potassium carries its own caution: supplementing it without medical guidance can affect heart rhythm in people with kidney problems, which is one more reason "more electrolytes, always" isn't the right default.

Similar logic applies to how much water you actually need day to day: the right amount depends on activity, heat and body size, not a flat daily number, and the same is true for which electrolyte form, like comparing magnesium glycinate against citrate, actually fits your situation.

Our take

These products aren't a scam, and the sports science behind sodium replacement during heavy sweat loss is solid. But "works for triathletes mid-race" and "everyone needs this daily" are different claims, and only the first one has real evidence behind it. Match the product to your actual sweat rate and session length, not the ad.

This is general information, not medical advice. Talk to a clinician before changing anything, especially if you are pregnant, nursing, or managing a condition.