Electrolyte Supplements: When You Need Them, When You Don't, and What to Look For

You need electrolyte supplementation if you sweat heavily (1+ hours of intense exercise), eat very low carb (keto/carnivore), fast regularly, have chronic diarrhea or vomiting, or work outdoors in heat. Outside these situations, food and water handle it.

When you sweat, you lose primarily sodium (about 900mg per liter of sweat), along with smaller amounts of potassium, magnesium, and calcium. Most commercial sports drinks are loaded with sugar and low on actual electrolytes. Gatorade has 160mg sodium per 12oz. That barely replaces what you lose in 15 minutes of hard exercise.

Keto and low-carb dieters are a special case. Insulin (which drops on keto) tells your kidneys to retain sodium. When insulin drops, your kidneys dump sodium. This is why people get "keto flu." It's not a carb withdrawal. It's an electrolyte crash. Supplementing 2,000-5,000mg sodium, 1,000-3,500mg potassium, and 300-500mg magnesium daily fixes it for most people.

Sodium is the most important electrolyte to replace when sweating. Despite decades of salt-fear messaging, most active people under-consume sodium. If you exercise heavily and eat a low-sodium whole food diet, you might actually need 3,000-5,000mg daily. That said, people with hypertension should follow their doctor's sodium guidance.

Potassium is the most under-consumed mineral in the American diet. The adequate intake is 2,600-3,400mg daily. Most people get about 2,500mg from food. A deficit of even a few hundred milligrams can cause muscle cramps, fatigue, and irregular heartbeat. Potassium supplements are capped at 99mg per pill by FDA regulation (because high-dose potassium pills can be dangerous for people with kidney disease). Getting it from food (bananas, potatoes, avocados) or electrolyte drinks is easier.

Magnesium is covered extensively in our magnesium guide. For electrolyte purposes, magnesium citrate or malate work well. 200-400mg daily. If you're cramping during or after exercise despite hydration, magnesium is often the missing piece.

Look for products with at least 500mg sodium, some potassium, some magnesium, and minimal sugar. If the label leads with flavoring and has 50mg sodium, it's a flavored water, not an electrolyte supplement.

DIY electrolyte mix: 1/4 teaspoon salt (590mg sodium), 1/4 teaspoon potassium chloride (NoSalt brand, about 650mg potassium), squeeze of lemon, water. Costs pennies. Works great. Tastes salty (because it is).

Tablets like Nuun are convenient for travel and moderate exercise. They're not high enough for heavy sweat sessions though.

Avoid products with lots of added B vitamins, caffeine, or other "extras." You're buying electrolytes. Keep it simple.