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.
We ranked every magnesium supplement we could verify on one scale: the elemental dose against the range used in research, the form and its absorption, third-party testing, verified reviews, and price per serving.
Two things decide most of the score: the form and the elemental dose. Oxide is cheap and poorly absorbed; glycinate and citrate absorb well and sit behind most of the research on sleep, cramps and stress. A label that lists “500mg magnesium” tells you nothing until you find the elemental figure — that is the number our dose bar tracks.
Prices are checked at publication and re-checked monthly. Where a brand changed its formula and we could not re-verify the new label, we say so rather than guess. Read the full method →