How long does magnesium citrate take to work?

Question

And how much should I consume?

Answer 1

Magnesium citrate solutions generally produces bowel movement in one half to six hours.

The following is taken from wikipedia:

Dosage

The maximum upper tolerable limit for magnesium supplementation in adults is 350 mg per day of elemental magnesium according to the National Institutes of Health (NIH).[1] In addition, according to the NIH, total dietary requirements for magnesium from all sources (i.e. food and/or supplements) is 360 mg of elemental magnesium per day. 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 seven to ten fluid ounces (the latter being 300 mL), followed immediately with a full eight fluid-ounce glass of water. Consuming an adult dose of 10 oz of laxative syrup (@ 1.745 g/oz) implies a consumption of 17.41 g of magnesium citrate in a single 10 oz dose resulting in a consumption of approximately 2000 mg of elemental magnesium per single dose. Given that this laxative dose contains 6 times the normal nutritional dose for magnesium, caution should be taken to avoid prolonged usage (i.e. over 5 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.