Magnesium citrate is effective for treating leg cramps in pregnant women in divided doses of 1.07 grams in the morning and 2.14 grams in the evening, claim Young and Jewell. For the lactate salt, the dosage is 1.01 grams in the morning and 2.02 grams in the evening.
The recommended daily intake of dietary magnesium is around 400 milligrams for adult males and around 300 milligrams for adult females, reports the National Institutes of Health. Low levels of other dietary minerals, such as potassium and calcium, can also cause muscle cramps, notes Mayo Clinic. There is insufficient evidence to demonstrate the effectiveness of magnesium in preventing other types of cramps, such as skeletal muscle cramps in older adults and exercise-associated muscle cramps, according to Garrison et al.