Use and Dosage
The maximum Upper Tolerable Limit for magnesium in supplement form for adults is 350 mg per day of elemental magnesium according to the National Institutes of Health (NIH). In addition, according to the NIH, total dietary requirements for magnesium from all sources (i.e. food and supplements) is 320–420 mg of elemental magnesium per day, though there is no UTL for dietary Magnesium. As a laxative syrup with a concentration of 1.745 g of magnesium citrate per fl. oz, a typical dose for adults and children twelve years or older is between 7 and 10 US fluid ounces (210 and 300 ml; 7.3 and 10 imp fl oz), followed immediately with a full 8 US fluid ounces (240 ml; 8.3 imp fl oz) glass of water. Consuming an adult dose of 10 oz of laxative syrup (@ 1.745 g/oz) implies a consumption of 17.45 g of magnesium citrate in a single 10 oz dose resulting in a consumption of approximately 2.0 g of elemental magnesium per single dose. Given that this laxative dose contains five times the recommended nutritional dose for magnesium, caution should be taken to avoid prolonged usage (i.e. over five days) and to follow the manufacturer's instructions strictly. For children between three and twelve years of age, the typical dose is roughly half that, based on physician recommendation. Magnesium citrate is not recommended for use in children and infants two years of age or less.
Although less common, as a magnesium supplement the citrate form is sometimes used due to its increased bio-availability to other common pill forms, such as magnesium oxide. However, according to one study, magnesium gluconate is marginally more bio-available than magnesium citrate.
Magnesium citrate, as a supplement in pill form, is useful for the prevention of kidney stones.
Read more about this topic: Magnesium Citrate