Magnesium is one of the most common supplements, yet the form on the label changes how well it absorbs and what it is best used for. Buying "magnesium" without checking the form is how people end up disappointed.

The common forms

FormOften used forNotes
GlycinateSleep, relaxationGentle on the stomach, well absorbed
CitrateOccasional constipationAbsorbs well; can loosen stools
OxideCheap general usePoorly absorbed; high elemental content
MalateDaytime energyOften taken earlier in the day
L-threonateCognitive supportStudied for brain uptake
Reading tip: the label amount may refer to the compound, not the elemental magnesium. Elemental content is what your body actually uses, so check both numbers.

How to choose

Match the form to the goal: glycinate for evening calm, citrate if regularity is the issue, malate for a daytime option. Start at the lower end of the range and give it a week or two.

Magnesium can interact with certain medications, so check with your clinician if you take prescription drugs, especially for the heart or kidneys.