Calcium tightens, magnesium loosens.
I have a problem with cramps, and every once in a while I need
to do a Mg soak. You can try this on the cheap with Epsom Salts (any drugstore and most supermarkets).
I combine that with....
Swanson Ultra Magnesium Chloride Flakes 2.2 lb (35.27 oz) Flakes - Swanson Health Products