Daisy--After looking around for electrolytes in a ready made package, I found that "Emergen-C" had 50 mg calcium, 60 mg magnesium, and, most importantly, 200 mg of potassium per package. That's four times that found in Gatorade. In recent hikes over 5 miles, 2 packages of Emergen-C in a pint or quart of water taken upon reaching camp for the night has prevented cramps. A problem is that I have to force feed myself the drink as I am too tired to be thirsty. The taste is OK. Before finding this remedy I often had severe hamstring cramps in the tent. At age 69, I now have more comfort in extending the comfort zone.