Experts say melatonin regulates circadian timing while magnesium aids relaxation, but trial evidence is mixed and benefits depend on individual sleep‑timing issues or magnesium deficiency.
Şebnem Ünlüişler, a genetic engineer at the London Regenerative Institute, explained that melatonin is a hormone that signals biological night and is most useful for sleep‑timing problems such as jet lag, shift work or delayed sleep schedules. She described magnesium as an essential mineral that supports nerve and muscle function and may aid relaxation, particularly in people with low dietary intake or deficiency.
Two randomized, placebo‑controlled trials are cited. A 2024 Sleep Medicine study found that 1 g of magnesium L‑threonate daily for three weeks improved sleep in 80 adults aged 35‑55 with sleep complaints. A 2025 Nature and Science of Sleep trial reported modest improvements in insomnia among 155 adults aged 18‑65 who took 250 mg of magnesium bisglycinate daily for four weeks. A 2024 Cureus review of multiple magnesium trials concluded that the evidence is too mixed to draw a strong overall conclusion.
Both experts agreed that magnesium may help those with a dietary deficiency or muscle‑related sleep issues, whereas melatonin may be more appropriate for circadian‑related problems. They cautioned that neither supplement is universally effective, side effects such as gastrointestinal upset for magnesium and next‑day drowsiness or medication interactions for melatonin are possible, and kidney impairment requires medical guidance. The available reporting notes that evidence for magnesium as a general sleep aid remains limited and mixed.