When it comes to electrolytes and GU products, we typically focus on sodium chloride (salt) replenishment above all else. Why do we do this? Well, when you look at the typical electrolyte concentration of adult sweat, you’ll see that the largest losses are from sodium and chloride, with magnesium losses only comprising a small amount (0-36 mg/L of sweat). Since the average athlete loses about 1-3 liters of sweat per hour, it is far more important to replace the largest constituent electrolytes (sodium and chloride) than the lowest (magnesium). It is worth noting, however, that we include 9 mg magnesium per capsule in our Roctane Electrolyte Capsules. If athletes are concerned over heavy sweat losses incurred during hot/humid conditions or very prolonged (> 4 hours) exercise, they might consider adding electrolyte capsules to their nutrition strategy. The general recommendation there would be to take 1-2 capsules per hour of activity, in addition to sports drinks, gels, chews, etc. This would help offset losses of sodium, chloride, and magnesium simultaneously.