Evidence B · Good
Water-soluble
Chronic
ATP cofactor (the Mg-ATP form) and >300 enzymes. It maintains the Na+/K+ pump and acts as a counterbalance to calcium (muscle relaxation). Losses are high through sweat plus cortisol in ultras.
Dose300–500 mg elemental Mg/day
Morning/trainingMalate (energy/Krebs)
NightBisglycinate (sleep)
HeartTaurate (rhythm)
4 functions in hydration
- Na/K-ATPase pump: requires Mg-ATP to pull K+ into the cell and push Na+ out.
- Counterbalance to calcium: prevents uncoordinated contraction (cramps).
- ATP activation: ATP is only biologically active as Mg-ATP.
- Preventing losses under stress: cortisol flushes Mg out through urine.
Forms to avoid
- Magnesium oxide: very low absorption (~4%), strong laxative effect.
- Pure chloride: may irritate the stomach during long races.
Strategy during a race
Quality salt capsules deliver 50–100 mg of Mg per Na/K dose. Check your product — Mg without Na is less effective for hydration.
How to combine forms
- Malate: morning or pre-workout (200 mg) — sustains Krebs/energy.
- Bisglycinate: before sleep (200–400 mg) — relaxation + sleep.
- Taurate: optional for cardiovascular support during long races.
Product in use: Magnen B6® (Marjan)
Available in Brazilian pharmacies (Drogasil, Drogaria São Paulo, etc.). Each tablet contains:
- 722.2 mg of magnesium glycinate = 130 mg of elemental Mg
- 1 mg of pyridoxine hydrochloride (Vitamin B6)
Dosage (label): 2 tablets/day in 1 or 2 intakes, after meals. Total: 260 mg of elemental Mg + 2 mg of B6.
Why B6 matters
- Pyridoxine is an essential cofactor in the synthesis of neurotransmitters (GABA, serotonin, dopamine).
- It optimizes magnesium uptake into cells — a synergistic effect.
- It reduces cramps of neuromuscular origin in endurance athletes.
💡 Practical strategy: since Magnen B6 uses glycinate (a calming form), it is more useful taken in the second half of the day (after lunch + after dinner). For morning energy support, the ideal would be to add Magnesium Malate separately — or simply accept that glycinate covers general needs.
⚠️ Contraindication: Magnen B6 is contraindicated in severe renal insufficiency (impaired magnesium excretion).