2 forms studied
Does magnesium help with back pain?
Yes — but only in one form. Magnesium Oxide is the one that was tested, and the others sold for this do not carry the same evidence.
Form by form
Strongest first. Evidence for one salt or ester is not evidence for another, so each is rated on its own trials.
Magnesium OxideSolid
Trials used 300–400 mg · 1 study · tested as IV magnesium sulfate (2 weeks) followed by oral magnesium oxide + gluconate (4 weeks) — not glycinate
Magnesium GlycinateNot verified
Trials used 300–400 mg · 2 studies · tested as magnesium sulfate (intravenous) and magnesium oxide + magnesium gluconate (oral) in Yousef 2013; unspecified oral magnesium salt in Bayram 2021
Worth knowing before you buy. Magnesium Glycinate is widely sold for back pain, but the trials behind that use tested magnesium oxide instead.