What electrolytes actually are (and why you're probably not getting enough)

"Electrolytes" is one of those words that gets thrown around in wellness marketing until it stops meaning anything. So let's start over.

An electrolyte is a mineral that, when dissolved in water, splits into electrically charged particles called ions. Those ions do two things in your body: they let water cross cell membranes, and they let nerve and muscle cells fire. Without them, you don't function.

The three that matter most

Your body uses several electrolytes — sodium, potassium, magnesium, calcium, chloride, phosphate, bicarbonate. Three of them do the bulk of the work and are the ones you can actually run low on through a normal day.

Sodium (Na⁺) — the water carrier

Sodium's main job is to hold water in your bloodstream and your extracellular spaces. When sodium concentration drops, water moves out of the blood and into the cells, then leaves the body via the kidneys. Low sodium = low blood volume = low energy, dizziness, and impaired thinking.

Sodium is the electrolyte you lose most aggressively through sweat. It's also the one most under-supplied in modern "clean" diets and most aggressively cut from "healthy" food products.

Potassium (K⁺) — the counterbalance

Potassium works opposite to sodium. Sodium dominates the fluid outside your cells; potassium dominates the fluid inside them. The two play a constant balancing act that regulates everything from blood pressure to heart rhythm to muscle contraction.

Most adults in Northern Europe under-consume potassium. It's the mineral in fruits, vegetables, beans and dairy — the foods modern diets quietly crowd out.

Magnesium (Mg²⁺) — the steady hand

Magnesium is involved in over 300 enzymatic reactions in your body, including ATP production (the actual currency of cellular energy). Low magnesium often shows up as muscle twitches, poor sleep, persistent fatigue, and exercise intolerance.

Magnesium quality matters: magnesium oxide, the cheapest form, is poorly absorbed. Magnesium citrate (what Repleo uses) has dramatically better bioavailability.

How they actually work together

When you actually need them

The honest answer: most people, most of the time, do not need an electrolyte supplement. A balanced diet with a normal amount of salt covers daily life.

You start needing them when something pushes you out of baseline: prolonged sweating (heat, exercise, manual work), low-carb or fasting protocols, illness with vomiting or diarrhoea, alcohol the night before, long flights, hot holidays, or a clean diet combined with a heavy training schedule.

In those situations, getting the right dose matters more than having "an" electrolyte product. Underdosed products won't move the needle; overdosed ones can taste rough and trigger gut issues. The sweet spot is roughly 1,000 mg sodium, 300 mg potassium and 80 mg magnesium per litre — which is, not coincidentally, the Repleo formulation.