Electrolytes are minerals that carry an electric charge when dissolved in water or body fluids. The seven main electrolytes in your body are sodium, potassium, calcium, magnesium, chloride, bicarbonate, and phosphate. Each plays a distinct role, from keeping your heart beating in rhythm to maintaining the strength of your bones. When people ask “what is in electrolytes,” they’re usually asking one of two things: what electrolytes are made of biologically, or what’s actually inside those electrolyte drinks and powders. The answer to both starts with the same handful of minerals.
The Seven Major Electrolytes
Your body depends on seven electrically charged minerals to function. They’re dissolved in your blood, sweat, urine, and the fluid inside your cells, and they do far more than “hydrate” you.
- Sodium controls how much fluid your body retains and helps nerves and muscles fire properly.
- Potassium keeps your cells, heart, and muscles working. It partners with sodium in almost every nerve signal your body sends.
- Calcium builds and maintains bones and teeth, but it also triggers muscle contractions and helps blood clot.
- Magnesium supports muscle and nerve function, heart rhythm, blood pressure, and blood sugar regulation.
- Chloride helps maintain fluid balance, blood volume, and blood pressure.
- Bicarbonate acts as a buffer that keeps your blood’s pH in a very narrow safe range. It also shuttles carbon dioxide through your bloodstream to your lungs for exhaling.
- Phosphate works alongside calcium to strengthen bones and teeth and plays a role in how your body stores and uses energy.
How Electrolytes Work in Your Body
The most fundamental job of electrolytes is maintaining an electrical gradient across every cell membrane in your body. Sodium concentrates outside your cells while potassium concentrates inside them, and a specialized pump constantly keeps it that way. This difference in charge is what generates the resting electrical potential of your cells, the baseline voltage that makes nerve impulses and muscle contractions possible.
When a nerve signal travels down your arm to move your fingers, sodium rushes into the cell and potassium rushes out in a rapid, sequential wave. That wave reaches the muscle, triggers calcium release inside the muscle fiber, and the muscle contracts. Without adequate levels of any of these minerals, the signal slows, weakens, or misfires entirely, which is why muscle cramps and heart rhythm problems are hallmark signs of electrolyte imbalance.
Bicarbonate and chloride handle a different but equally critical task. Your blood needs to stay between a pH of 7.35 and 7.45. Carbon dioxide produced by your cells combines with water to form carbonic acid, which then splits into bicarbonate and a hydrogen ion. This buffering reaction absorbs excess acid and prevents your blood from becoming dangerously acidic. Your kidneys fine-tune the process by reabsorbing or excreting bicarbonate as needed.
What’s in Electrolyte Drinks and Powders
Commercial electrolyte products contain the same minerals your body uses, just in isolated, concentrated form. The core ingredients in nearly every product are sodium, potassium, and chloride, because those are the primary electrolytes lost in sweat. Many products also include smaller amounts of calcium and magnesium.
On an ingredient label, you won’t see “sodium” by itself. Instead, you’ll find compound names like sodium chloride (table salt), potassium chloride, magnesium citrate, or calcium carbonate. These are just the chemical forms the minerals take when they’re in a dry powder or dissolved in liquid. Once they hit water (or your stomach), they separate into their individual charged particles and work the same way as the electrolytes in food.
Most electrolyte drinks also contain sugar or some form of glucose. This isn’t just for flavor. Glucose and sodium are absorbed together through the same transport system in your small intestine, so having both present speeds up water absorption significantly. The World Health Organization’s oral rehydration formula uses a 1:1 ratio of glucose to sodium for this reason. Sports drinks typically add more sugar than that formula calls for, which improves taste but can slow absorption if the concentration gets too high.
Some products marketed as “zero sugar” replace glucose with sugar alcohols or artificial sweeteners. These still deliver the minerals, but they lose the absorption advantage that glucose provides. For casual hydration this rarely matters, but during heavy sweating or illness with fluid loss, a formula with some real sugar works faster.
How Much You Need Daily
The daily targets vary by mineral. For potassium, the adequate intake is 3,400 mg per day for adult men and 2,600 mg for adult women. Most Americans fall well short of that. For sodium, mainstream guidelines suggest staying under 2,300 mg per day, though athletes and people who sweat heavily may need more. Magnesium recommendations sit around 400 to 420 mg for men and 310 to 320 mg for women. Calcium targets are 1,000 mg for most adults, rising to 1,200 mg for women over 50.
These numbers sound large, but a varied diet covers most of them without supplements. The gap most people face is in potassium and magnesium, partly because both are concentrated in foods that many people under-eat: leafy greens, beans, and whole fruits.
Food Sources by Electrolyte
You don’t need a supplement or a sports drink to get electrolytes. Whole foods deliver them alongside fiber, vitamins, and other nutrients that isolated supplements don’t provide.
For potassium, the richest sources aren’t bananas (451 mg per medium banana) but leafy greens and legumes. A cup of cooked beet greens delivers 1,309 mg, nearly 40% of a man’s daily target. A cup of cooked Swiss chard has 961 mg. Lima beans provide 969 mg per cooked cup, and a medium baked potato with the skin on tops 900 mg. Even a cup of plain nonfat yogurt provides 625 mg. Prune juice, tomato paste, clams, and acorn squash are all quietly among the most potassium-dense foods available.
Calcium is most concentrated in dairy products, fortified plant milks, canned sardines and salmon (eaten with bones), tofu made with calcium sulfate, and leafy greens like kale and bok choy. Magnesium is richest in pumpkin seeds, almonds, spinach, black beans, and dark chocolate. Sodium and chloride come primarily from salt, which most people get plenty of from processed and restaurant food.
Signs of Electrolyte Imbalance
Each electrolyte produces distinct symptoms when levels drop too low or climb too high, but there’s significant overlap. Muscle weakness, cramping, and irregular heartbeat show up across almost every type of imbalance, which is why a blood test is the only reliable way to identify the specific problem.
Low sodium tends to cause headache and confusion, and in severe cases can progress to seizures. Low potassium produces weakness, fatigue, and a faint or irregular pulse. Low magnesium triggers nausea, leg cramps, tremors, and can also cause heart rhythm disturbances. Low calcium leads to numbness and tingling, especially around the mouth and fingertips, and can cause involuntary muscle spasms.
Excess levels carry their own risks. Too much potassium is particularly dangerous because it can cause life-threatening heart rhythm changes. Too much sodium causes fluid retention, thirst, and irritability. Too much calcium leads to nausea, constipation, and excessive thirst. These extremes are uncommon from diet alone and typically result from kidney problems, certain medications, or overcorrection with supplements.
Mild, temporary imbalances are common during heavy exercise, bouts of vomiting or diarrhea, and extreme heat exposure. In these situations, replacing fluids along with sodium and potassium (through food, a drink, or an oral rehydration solution) is usually enough to restore balance within hours.