Evidence A · Strong (safety)
Water-soluble
Acute
A mix of essential electrolytes for replenishment during prolonged training and long races. It combines sodium, potassium, magnesium, and calcium in proportions optimized for replacement through sweat — unlike standalone magnesium products (such as Magnen B6 or Neuro-Mag), which serve a metabolic/cognitive purpose rather than acute replacement.
Why it matters for ultramarathon
- Sodium: the main electrolyte lost in sweat (200–2,000 mg/L). Replacing it prevents dilutional hyponatremia in races >4h.
- Potassium: essential for nerve conduction and muscle contraction; lost in smaller amounts than sodium.
- Magnesium: regulates muscle relaxation (prevents cramps) and ATP activation.
- Calcium: muscle contraction; in long races, it helps avoid "exhaustion cramps".
Product in use: Nutricost Electrolyte Complex
Nutricost Electrolyte Complex (capsule version) delivers a complete blend in a practical, portable format. Typical composition per capsule:
- Sodium (Himalayan rock salt + KCl) — ~125 mg
- Potassium (KCl) — ~100 mg
- Magnesium (di-magnesium malate) — ~30–60 mg
- Calcium — ~40 mg
- Chloride, Zinc, B6, B12
Bottle120 capsules
Daily use1 capsule (maintenance)
Race use1–2 caps/hour during effort
FoodIndependent; with water
Usage strategy
- Day-to-day (maintenance): 1 cap in the morning with water — useful in hot climates or if your diet is low in sodium (e.g. low-carb, prolonged fasting).
- Long sessions (Z2 >90 min): 1 cap every 60–90 min of effort, with 200–500 ml of water.
- Race/Ultra (>3h): 1–2 caps per hour depending on the heat and your personal sweat rate.
- Pre-race: 1 cap 60 min before the start with 500 ml of water helps "load" your stores.
⚠️ Hyponatremia: in ultras >4h, the risk of death from hyponatremia (sodium <135 mmol/L) is greater than from mild dehydration. Don't drink water alone — always replace sodium. Early symptoms: nausea, headache, swollen fingers, weight gain during the race.
How to find your personal rate
- Patch test (Precision Hydration, h2pro): measures the sodium in your sweat directly.
- Weigh yourself before/after a session: estimates total fluid loss. Each 1 kg lost = ~1 L of sweat.
- "Salty sweater": sweat that leaves white marks on your clothes = you need more sodium.
Difference vs. Magnen B6 and Neuro-Mag
- Magnen B6 (Glycinate + B6): standalone magnesium for chronic metabolic/muscular support (daily use).
- Neuro-Mag (L-Threonate): magnesium that crosses the blood-brain barrier for cognition and sleep.
- Nutricost Electrolyte Complex: a complete mix for hydro-electrolyte replacement during effort/heat.
- The 3 are complementary, not redundant — they act on different compartments and purposes.
Trusted brands (alternatives)
- LMNT: powder sachet, high sodium (1000mg/sachet), sugar-free — the standard for low-carb.
- SaltStick FastChews/Caps: precise doses, easy to take while running.
- Precision Hydration: lines with different concentrations (PH500, PH1000, PH1500) — choose according to your patch test.
- Liquid IV: a mix with glucose for absorption via SGLT1 (race use).
Evidence
- Wilderness Medical Society — Exercise-associated hyponatremia WMS Practice Guidelines
- ISSN: hydration and endurance performance JISSN