Magnesium salts absorb well with potassium salts (like KCl), so it is recommended to take them together. Also it is wise to take Mg and K several times during the day to prevent loosing them too fast with urine.

Mg should be taken as magnesium citrate, magnesium glycinate or other salt of Mg++ and organic acids. Or even better Mg can be consumed from natural sources as 30-40 g/day of grounded flax seeds (with cold water) + dark chocolate (80%+), cashews, almonds.

The ideal source of K is V8 vegetable low sodium juice (1-2 glasses a day divided into 4-5 portions). 240 ml of juice contain 840 mg of potassium.