The B vitamins can be confusing, primarily because there are so darn many of them. However, they’re important for health, especially for producing energy and metabolizing macronutrients, and are critical for immune and nerve function. And many athletes are deficient in B vitamins because of their intense training regimens. If you train hard, then it’s in your best interest to best the B’s. Choose a B complex that provides 100 milligrams of B-1 (thiamine), B-2 (riboflavin), B-3 (niacin), B-5 (pantothenic acid) and B-6 (pyridoxine), and at least 100 micrograms of B-7 (biotin), B-9 (folic acid) and B-12 (cyanocobalamin). And remember, B vitamins are water-soluble, which means your body can’t store them, so take one dose in the morning and another with your evening meal.