As I have aged I have been plagued by more muscle cramps than before. I am not drinking any less water, or even doing anything differently. The muscle cramps come at night out of the blue when I am the most relaxed. Last year I was religious about taking one multivitamin and one calcium-magnesium pill each night and it did see a bit better. The most painful cramps are the hamstring cramps. Ouch! And when in a sleeping bag and small tent it is almost impossible to quickly get out and stand up to stretch the muscle. And maybe it is female specific- I recall my mother also having serious post-menopausal muscle cramp issues. Since the vitamins seemed to help, does anyone know of a supplement designed specifically for muscle cramps?