Topical magnesium: hype vs. evidence for sleep and restless legs
Magnesium is essential and best obtained via diet or oral supplements to address deficiencies (Health Canada notes many adults are deficient, with recommended intakes of about 320 mg/day for women and 420 mg/day for men). Topical magnesium (lotion, oil, spray) is popular for sleep and restless legs, but evidence for meaningful skin absorption is limited and large trials are lacking; a 2017 study found higher blood magnesium with transdermal use, but the difference wasn’t statistically significant. While anecdotes tout quick relief, experts generally consider topical forms safe but unproven for broad benefits, so consult a clinician and prioritize oral magnesium for deficiency.