Does magnesium citrate make you poop?
The bottle, yes. A capsule, probably not. Magnesium citrate comes as a laxative drink and as an everyday supplement. They're very different doses. Pick yours:
YES, that's its job.
The label says it usually works in 30 minutes to 6 hours. Half a bottle (5 fl oz) carries about 1,400 mg of magnesium, four times the daily supplement limit, on purpose.
How much magnesium is in one dose
Daily limit from supplements: 350 mg (NIH)
The black line is the 350 mg daily supplement limit. Amounts are elemental magnesium, the number on the label's Supplement Facts and the number the limit counts.
Did magnesium citrate make you go?
The meter says what should happen. Your bowels get a vote too.
Why it works
It pulls water into your gut
Magnesium your body doesn't absorb stays in the bowel and holds water there. More water means softer, faster stool. The laxative bottle is built around that.
Dose is everything
A laxative dose is several times the amount in a daily supplement. NIH puts the limit for magnesium from supplements and medicines at 350 mg a day for adults.
Better absorbed than oxide
NIH notes that citrate is absorbed more completely than forms like oxide. At normal supplement doses that means less left behind to loosen you up.
Sources: NIH Office of Dietary Supplements, Magnesium fact sheet; MedlinePlus, Magnesium citrate; Magnesium citrate oral solution, Drug Facts label.