Electrolytes are minerals that carry an electrical charge when dissolved in body fluids — blood, sweat, urine, and intracellular fluid. They are not optional supplements or something you only need after a marathon. Electrolytes regulate your heartbeat, control muscle contraction and relaxation, maintain fluid balance between cells, support nerve signal transmission, regulate blood pH, and enable virtually every biochemical reaction in your body.

The six major electrolytes are sodium, potassium, magnesium, calcium, chloride, and phosphate. Imbalances in any of them can cause symptoms ranging from mild fatigue and muscle cramps to life-threatening cardiac arrhythmias. And yet, most people have no idea how much they are consuming or whether they are getting enough.

This guide covers each electrolyte in detail — what it does, how to recognize deficiency, the best food sources, when supplementation makes sense, and how commercial electrolyte products compare to simple homemade solutions.

The Six Major Electrolytes: Functions and Deficiency Signs

1. Sodium (Na+)

Sodium is the primary electrolyte in extracellular fluid (the fluid outside your cells). It is essential for fluid balance, nerve impulse transmission, and muscle contraction. Despite its reputation as a dietary villain, sodium is critical — your body cannot function without it.

Daily needs: The Adequate Intake (AI) is 1,500 mg/day for adults. The Dietary Guidelines for Americans recommend staying below 2,300 mg/day. However, athletes, heavy sweaters, and people on low-carb or keto diets may need 3,000–5,000 mg/day due to increased excretion.

Deficiency (hyponatremia) symptoms:

Headache, confusion, brain fog
Nausea, vomiting
Muscle weakness, cramps, spasms
Fatigue, low energy
Dizziness, especially upon standing
In severe cases: seizures, coma (medical emergency)

Who is at risk: Endurance athletes who drink excessive plain water without sodium (exercise-associated hyponatremia), people on very low-sodium diets, those taking diuretics, people following keto or intermittent fasting (insulin drops cause kidneys to excrete more sodium).

Key insight: Hyponatremia from overhydration is more dangerous than dehydration in endurance events. A study in the New England Journal of Medicine found that 13 percent of Boston Marathon finishers had hyponatremia — many from drinking too much water without adequate sodium replacement.

2. Potassium (K+)

Potassium is the primary electrolyte inside cells (intracellular). It works in opposition to sodium to regulate fluid balance, and it is essential for heart rhythm, muscle function, and nerve signaling. Potassium also helps blunt the blood pressure-raising effects of sodium — the sodium-to-potassium ratio may matter more than absolute sodium intake for cardiovascular health.

Daily needs: 2,600 mg/day for women, 3,400 mg/day for men (AI). Most Americans consume only 2,300–2,600 mg/day, making potassium one of the most common nutritional shortfalls.

Deficiency (hypokalemia) symptoms:

Muscle weakness, cramps, twitching
Fatigue, lethargy
Heart palpitations, irregular heartbeat
Constipation (smooth muscle in the gut requires potassium)
Numbness or tingling
In severe cases: dangerous cardiac arrhythmias, paralysis

Best food sources: Potatoes (926 mg per medium potato), bananas (422 mg), avocado (690 mg per whole), spinach (839 mg per cup cooked), sweet potatoes (541 mg), white beans (1,004 mg per cup), salmon (534 mg per 6 oz), coconut water (600 mg per cup).

For the complete picture on potassium, including how much you need by age and activity level, see our guide on potassium deficiency symptoms.

3. Magnesium (Mg2+)

Magnesium participates in over 300 enzymatic reactions, including energy production (ATP synthesis), protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. It is also essential for the active transport of calcium and potassium across cell membranes — making it critical for normal heart rhythm and muscle contraction.

Daily needs: 310–320 mg/day for women, 400–420 mg/day for men. Up to 68 percent of Americans do not meet the RDA.

Deficiency (hypomagnesemia) symptoms:

Muscle cramps, twitches, tremors
Fatigue, weakness
Anxiety, irritability, mood changes
Insomnia, difficulty staying asleep
Heart palpitations
Headaches and migraines
Numbness, tingling
Loss of appetite, nausea

Magnesium deficiency is often called the "silent deficiency" because standard blood tests (serum magnesium) only measure the 1 percent of body magnesium in the blood — you can be significantly depleted at the cellular level while showing normal serum levels. Red blood cell (RBC) magnesium is a more sensitive test. For the full rundown, see our guide on signs of magnesium deficiency.

4. Calcium (Ca2+)

While most people associate calcium with bones and teeth (which store 99 percent of body calcium), the 1 percent in the blood and soft tissues plays critical roles as an electrolyte: it is required for muscle contraction, nerve transmission, blood clotting, and hormone secretion. Your body maintains blood calcium levels within an extremely narrow range — if dietary intake is insufficient, it will pull calcium from bones to maintain these levels.

Daily needs: 1,000 mg/day for adults 19–50; 1,200 mg/day for women over 50 and men over 70.

Deficiency (hypocalcemia) symptoms:

Muscle cramps, especially in the calves and feet
Numbness and tingling in fingers, toes, and around the mouth
Brittle nails, dry skin
Fatigue
Difficulty swallowing
In severe cases: muscle spasms (tetany), seizures, abnormal heart rhythms

For a comprehensive guide to calcium needs, food sources, and supplementation, see our article on how much calcium you need.

5. Chloride (Cl-)

Chloride works alongside sodium to maintain fluid balance and blood pressure. It is also a key component of hydrochloric acid (HCl) in the stomach, which is essential for protein digestion and pathogen defense. Chloride deficiency is rare in isolation — it typically accompanies sodium deficiency because the main dietary source is sodium chloride (table salt).

Daily needs: 2,300 mg/day (AI). Easily met through normal salt intake.

Deficiency symptoms: Loss of appetite, muscle weakness, lethargy, dehydration, alkalosis (elevated blood pH). Most commonly seen in people with prolonged vomiting, excessive sweating without replacement, or chronic diuretic use.

6. Phosphate (PO4 3-)

Phosphorus (consumed as phosphate) is the second most abundant mineral in the body after calcium. It is essential for ATP production (cellular energy), bone and tooth formation, DNA and RNA structure, and acid-base balance. Phosphorus deficiency is uncommon because it is found widely in the food supply — meat, dairy, grains, and legumes are all rich sources.

Daily needs: 700 mg/day for adults. Most people easily meet this through diet.

Deficiency (hypophosphatemia) symptoms: Muscle weakness, bone pain, loss of appetite, numbness, irritability, confusion. Most commonly seen in cases of chronic alcohol use, refeeding syndrome, certain kidney disorders, or excessive antacid use (which binds dietary phosphorus).

Electrolytes and Exercise: When You Need More

During exercise, you lose electrolytes primarily through sweat. The composition of sweat varies widely between individuals, but on average:

Electrolyte	Average Loss per Liter of Sweat	High Sweater Loss per Liter
Sodium	460–1,150 mg	Up to 2,300 mg
Potassium	160–390 mg	Up to 600 mg
Magnesium	0.3–2.1 mg	Up to 5 mg
Calcium	1.5–34 mg	Up to 60 mg
Chloride	540–1,580 mg	Up to 3,000 mg

Sodium is by far the most significant electrolyte lost in sweat. A moderate exerciser sweating 1 liter per hour loses roughly 500–1,000 mg of sodium — which is why post-workout replenishment should focus primarily on sodium, not the trace amounts of other electrolytes in sweat.

When You Need Electrolyte Supplementation During Exercise

Exercise lasting more than 60–90 minutes: For shorter sessions, water alone is usually sufficient for adequately nourished individuals
Hot and humid environments: Sweat rates increase dramatically — 2–3 liters per hour is common in hot conditions
Heavy sweaters: Some people produce significantly saltier sweat (visible salt stains on clothing)
Two-a-day training sessions: Insufficient recovery time to replenish electrolytes through food alone
Endurance events: Marathons, triathlons, long cycling — sodium replacement is critical to prevent hyponatremia

For workout nutrition strategies, including pre- and post-exercise electrolyte considerations, see our guide on what to eat before and after a workout.

Commercial Electrolyte Products: A Critical Comparison

The electrolyte supplement market has exploded in recent years. Here is how the most popular products compare:

Product	Sodium	Potassium	Magnesium	Sugar	Best For
LMNT	1,000 mg	200 mg	60 mg	0 g	High-sodium needs, keto, fasting, heavy sweaters
Liquid IV	500 mg	370 mg	0 mg	11 g	General hydration, moderate exercise
Nuun Sport	300 mg	150 mg	25 mg	1 g	Light exercise, daily hydration, low-calorie
Drip Drop ORS	330 mg	185 mg	39 mg	7 g	Medical-grade rehydration, illness recovery
Gatorade (20 oz)	270 mg	75 mg	0 mg	34 g	High-intensity exercise with carb needs
Pedialyte	370 mg	280 mg	0 mg	6 g	Illness recovery, pediatric dehydration
Coconut Water (1 cup)	252 mg	600 mg	60 mg	6 g (natural)	Natural option, high-potassium, light exercise

How to Choose

The "best" electrolyte product depends entirely on your situation:

For heavy exercise (90+ minutes) or heavy sweating: You need high sodium — LMNT or a similar high-sodium, low-sugar product. Gatorade works for exercise lasting 2+ hours where you also need carbohydrates for fuel.
For general daily hydration: Nuun Sport or plain water with a pinch of salt is usually sufficient. Most sedentary to lightly active people get adequate electrolytes from food.
For keto, low-carb, or fasting: LMNT or a similar zero-sugar, high-sodium product. Ketogenic diets and fasting both increase sodium excretion.
For illness recovery (vomiting, diarrhea): Drip Drop or Pedialyte, which use the WHO oral rehydration solution ratios for optimal absorption.

DIY Electrolyte Drinks: Simple, Cheap, Effective

You do not need a commercial product to replenish electrolytes. These homemade recipes work just as well for most situations:

Basic Electrolyte Water

32 oz (1 liter) water
1/4 teaspoon salt (sodium chloride) — provides ~590 mg sodium
1/4 teaspoon lite salt (potassium chloride) — provides ~350 mg potassium
Squeeze of lemon or lime for flavor
Optional: 1 tablespoon honey for taste and carbohydrate (if exercising)

Sport Electrolyte Drink

32 oz (1 liter) water
1/2 teaspoon salt — ~1,180 mg sodium
1/4 teaspoon lite salt — ~350 mg potassium
2 tablespoons honey or maple syrup — ~30 g carbohydrate
Juice of 1 lemon

Post-Workout Recovery

1 cup coconut water — ~600 mg potassium, ~252 mg sodium
Pinch of salt — additional 150–300 mg sodium
1/2 cup orange juice — additional potassium, vitamin C
1 cup water

The key ingredient in any electrolyte drink is sodium. "Lite salt" (a potassium chloride / sodium chloride blend, commonly sold as Morton Lite Salt or Nu-Salt) is the easiest way to add both sodium and potassium.

When You Do NOT Need Extra Electrolytes

The electrolyte supplement industry has a vested interest in making you believe everyone needs electrolyte supplementation. In reality, most people get adequate electrolytes from a balanced diet. You probably do not need extra electrolytes if:

You exercise for less than 60 minutes in moderate conditions
You eat a varied diet that includes fruits, vegetables, dairy or alternatives, and adequate salt
You are not following a very low-carb diet, fasting protocol, or extreme elimination diet
You are not experiencing any symptoms of deficiency
You are not a heavy sweater or exercising in extreme heat

Plain water is sufficient for hydration in most everyday situations. Adding electrolytes when you do not need them is not harmful (your kidneys will excrete the excess), but it is unnecessary expense. For an example of when extra electrolytes might matter around exercise, check our guide on how many calories swimming burns, which covers the unique hydration demands of water-based exercise.

Signs You May Have an Electrolyte Imbalance

Electrolyte imbalances share many symptoms with other conditions (dehydration, poor sleep, overtraining, nutritional deficiencies), which makes them easy to miss. Consider electrolytes as a possible cause if you experience:

Persistent muscle cramps or twitching — especially in the calves, feet, or eyelids
Fatigue that does not improve with rest
Headaches during or after exercise
Dizziness or lightheadedness when standing
Heart palpitations or irregular heartbeat
Excessive thirst despite drinking water
Dark urine — can indicate dehydration and sodium imbalance
Salt cravings — your body's signal that sodium stores are depleted
Brain fog or difficulty concentrating

If symptoms are persistent or severe — particularly heart palpitations, confusion, or severe muscle weakness — see a healthcare provider. A basic metabolic panel (BMP) blood test measures sodium, potassium, chloride, and calcium levels and is the standard diagnostic tool.

How to Track Your Electrolyte Intake

Most people have no idea how much sodium, potassium, magnesium, or calcium they consume on a daily basis. Generic calorie-tracking apps typically show sodium and sometimes calcium, but ignore magnesium, potassium, and chloride — the electrolytes most likely to be insufficient.

Açaí tracks all 245 micronutrients — including every electrolyte — from a single food photo. Instead of manually searching databases for the potassium content of your lunch, you photograph your plate and Açaí's AI calculates everything instantly. Over time, you can see whether you are consistently meeting your targets or falling short in specific electrolytes, allowing you to make targeted adjustments rather than guessing.

Download Açaí for iOS or Android.

Frequently Asked Questions

What are the symptoms of electrolyte deficiency?

Electrolyte deficiency symptoms vary by which electrolyte is depleted. The most common symptoms across all electrolyte deficiencies include muscle cramps and twitching, fatigue and weakness, headaches, dizziness, heart palpitations, nausea, and brain fog. Sodium deficiency (hyponatremia) specifically causes confusion, headache, and in severe cases seizures. Potassium deficiency (hypokalemia) causes muscle weakness, constipation, and irregular heartbeat. Magnesium deficiency causes muscle cramps, anxiety, insomnia, and migraines. Calcium deficiency causes numbness, tingling, and muscle spasms. If you experience persistent or severe symptoms, see a healthcare provider for a basic metabolic panel blood test.

Do I need electrolytes if I exercise?

For exercise lasting less than 60 minutes in moderate conditions, plain water is usually sufficient for adequately nourished individuals. For exercise lasting 60–90+ minutes, high-intensity exercise, exercise in hot or humid conditions, or if you are a heavy sweater, electrolyte supplementation — particularly sodium — is recommended. The primary electrolyte lost in sweat is sodium (500–1,000+ mg per liter of sweat), followed by chloride and potassium. After exercise, replenishing sodium is the highest priority. A simple approach: add a pinch of salt to your water or consume a salty post-workout meal.

What is the best way to replenish electrolytes naturally?

The best natural way to replenish electrolytes is through food. Potassium-rich foods include potatoes, avocados, bananas, spinach, and white beans. Magnesium-rich foods include pumpkin seeds, almonds, spinach, dark chocolate, and black beans. Calcium-rich foods include dairy products, sardines, kale, and fortified plant milks. Sodium is easily obtained from salting food to taste. Coconut water is a natural electrolyte drink that provides potassium, sodium, and magnesium. For a DIY electrolyte drink, mix 1 liter of water with 1/4 teaspoon salt, 1/4 teaspoon lite salt (potassium chloride), and a squeeze of lemon — this provides approximately 590 mg sodium and 350 mg potassium at minimal cost.

What app tracks electrolyte intake?

Most nutrition apps only track sodium and sometimes calcium, missing the electrolytes most commonly deficient — potassium and magnesium. Açaí tracks all 245 micronutrients including every electrolyte (sodium, potassium, magnesium, calcium, chloride, and phosphorus) from a single food photo. This makes it the most comprehensive option for monitoring electrolyte balance alongside your overall nutritional intake, without the tedium of manual database searching.

Is LMNT better than Liquid IV?

LMNT and Liquid IV serve different purposes. LMNT provides 1,000 mg sodium, 200 mg potassium, and 60 mg magnesium with zero sugar — making it ideal for high-sodium needs such as keto diets, fasting, heavy sweating, and endurance exercise. Liquid IV provides 500 mg sodium, 370 mg potassium, and 11 g sugar, using Cellular Transport Technology (CTT) based on the WHO oral rehydration solution — making it better for general hydration and moderate exercise. If your primary need is sodium replacement (keto, fasting, heavy sweating), LMNT is the better choice. For everyday hydration support with a balanced electrolyte profile, Liquid IV works well. Neither is necessary for most people who eat a balanced diet and exercise moderately.

Electrolytes: What They Are, Deficiency Symptoms, and How to Replenish Them