Independent supplement ratingsUS and Canada · Updated weekly
A ratings desk for a category that has spent thirty years grading its own homework.
A ratings desk for a category that has spent thirty years grading its own homework.
Citrate is one of the better-absorbed, better-value magnesium forms, which is why it shows up in a lot of the research and on a lot of budget-friendly labels. It delivers a real elemental dose without the premium price of some chelates.
Its defining trait is the laxative effect: magnesium citrate draws water into the bowel, which some people want and many don't. That makes it a great value pick if you tolerate it, and a poor one if you've had loose stools from magnesium before — in which case glycinate is gentler.
Same rule applies: judge it on elemental magnesium, and start low to see how your gut responds. Research on PubMed →
It depends entirely on what you are taking it for, and the two answers are very far apart. As a laxative, a full dose works within roughly 30 minutes to six hours — that is unabsorbed magnesium pulling water into the bowel. As a daily supplement to raise magnesium status, there is no same-day effect to feel; blood levels respond over days and the sleep trials that found anything ran for four to eight weeks.
Magnesium generally has modest support for falling asleep faster, and citrate is a well-absorbed form that qualifies. The trials pooling best used bisglycinate and other chelated forms, mostly because they are gentler at the doses involved. Citrate works; at the top of the range it is likelier to send you to the bathroom. The evidence is in magnesium for sleep.
Two things, at two different doses. At supplemental doses it contributes to your daily magnesium intake like any other form — muscle and nerve function, energy metabolism, sleep. At the much larger doses sold for bowel preparation it acts as an osmotic laxative. The same compound, doing entirely different work.
Citrate is cheaper per gram of elemental magnesium and absorbs well. Glycinate costs more and is easier on the stomach. For most people topping up, citrate is the better value; if you have had loose stools from magnesium before, pay the difference.
Reviewed by the NFS editorial team · Educational only — not medical advice.