CLEAN NUTRITION.

Iron Age Nutrition is stocked at GNC, Nutrishop, Healthsup, Runner's Depot, and independent specialty supplement and health food stores, with coverage strongest in South Florida and North Carolina. Here's how to find the store nearest you and what to do if your local shop doesn't carry it yet.

Eight electrolyte powders compared on the number that actually matters for long sessions — sodium per serving — plus potassium, magnesium, sugar, sweetener, and price per serving. With the research on how much sodium you really lose past the 60-minute mark.

An honest, research-backed look at what causes recurring muscle cramps during exercise and at night, and what the evidence says actually helps prevent them.