Electrolyte Supplements: Sodium, Potassium, Magnesium for Hydration

Medically reviewed by Dr. Sarah Mitchell, MD — Internal Medicine

See also: Best Electrolyte Supplements 2026: Powders, Pills & Drinks Compared | Potassium Supplements: Best Forms for Blood Pressure and Heart Health

What Are Electrolytes and Why Do They Matter?

Electrolytes are minerals that carry an electrical charge when dissolved in water. They’re essential for:

• Nerve signaling — Every thought and movement depends on electrolyte gradients
• Muscle contraction — Including your heartbeat
• Fluid balance — Regulating how much water is inside vs. outside cells
• pH balance — Maintaining blood pH within the narrow 7.35-7.45 range

The four primary electrolytes are:

1. Sodium (Na⁺) — Extracellular; fluid balance, nerve function
2. Potassium (K⁺) — Intracellular; heart rhythm, muscle function
3. Magnesium (Mg²⁺) — Intracellular; 300+ enzymatic reactions
4. Calcium (Ca²⁺) — Muscle contraction, bone structure

When Do You Need Electrolyte Supplementation?

✅ Likely to Benefit

• Athletes training >1 hour or in hot conditions
• Keto dieters — Ketosis increases sodium, potassium, and magnesium excretion
• After illness with vomiting or diarrhea
• Hot climate workers — Excessive sweating depletes all electrolytes
• Fasting — Reduced food intake means reduced electrolyte intake
• After alcohol consumption — Alcohol is a diuretic that wastes electrolytes

❌ Probably Don’t Need

• Sedentary individuals with normal diet
• Short exercise sessions (<1 hour)
• People eating 3 balanced meals daily

The Optimal Electrolyte Ratios

Best Electrolyte Forms

Sodium

• Sea salt or pink Himalayan salt — Best for food/cooking
• Sodium citrate — Best for supplements (gentle on stomach, enhances absorption)
• Sodium bicarbonate — Good for buffering lactic acid

Potassium

• Potassium citrate — Best absorbed, gentle, alkalizing
• Potassium gluconate — Good alternative
• Potassium chloride — Effective but can cause GI irritation at high doses

Magnesium

• Magnesium glycinate — Best for daily use, no laxative effect
• Magnesium citrate — Well-absorbed, mild laxative effect
• Magnesium malate — Best for energy and muscle pain
• Avoid: Magnesium oxide (poorly absorbed, strong laxative)

DIY Electrolyte Drink Recipe

For a cost-effective alternative to commercial electrolyte drinks:

• 1 liter water
• 1/4 tsp sea salt (500mg sodium)
• 1/8 tsp potassium chloride salt (400mg potassium)
• 1 tbsp honey or maple syrup (energy for athletes)
• Juice of 1 lemon (potassium + vitamin C)
• Optional: 100-200mg magnesium glycinate capsule

Cost: ~$0.50 per liter vs $3-5 for commercial electrolyte drinks.

Commercial Electrolyte Products: What to Look For

✅ Good signs:

• Contains sodium, potassium, AND magnesium
• Uses citrate or gluconate forms (not oxides)
• <5g sugar per serving (or sugar-free)
• No artificial colors or excessive additives

❌ Red flags:

• Only contains sodium (most sports drinks)
• Uses magnesium oxide

• 10g sugar per serving

• Contains high-fructose corn syrup
• “Proprietary electrolyte blend” (hides doses)

Electrolyte Imbalance: Warning Signs

Special Populations

Keto Dieters

Keto increases electrolyte excretion by 3-5x due to lower insulin levels. Most “keto flu” symptoms (headache, fatigue, muscle cramps) are actually electrolyte deficiencies. Increase sodium to 3000-5000mg, potassium to 3500-4700mg, and magnesium to 400-500mg daily.

Endurance Athletes

Marathon runners, cyclists, and triathletes can lose 1-2 liters of sweat per hour, containing 500-1500mg sodium, 100-300mg potassium, and 50-100mg magnesium. Replace electrolytes during exercise lasting >1 hour.

After Illness

Vomiting and diarrhea cause rapid electrolyte loss. The WHO’s oral rehydration solution formula:

• 1 liter water
• 6 tsp sugar
• 1/2 tsp salt
• 1/4 tsp potassium chloride