Experts say melatonin regulates circadian timing while magnesium aids relaxation, with limited mixed trial evidence and benefits tied to deficiency or clock‑related sleep problems.
Melatonin and magnesium act through different pathways, according to genetic engineer Şebnem Ünlüişler and GP Opel Baker. Melatonin is a hormone that signals the body’s night phase and is most useful for sleep‑timing issues such as jet lag, shift work or delayed schedules. Magnesium is an essential mineral that supports nerve and muscle function and may promote relaxation, especially in people with low dietary intake or deficiency.
Clinical evidence for magnesium as a sleep aid is mixed. A 2024 randomized controlled trial in Sleep Medicine reported that 1 g of magnesium L‑threonate daily for three weeks improved sleep in 80 adults aged 35‑55 with sleep problems versus placebo. A 2025 placebo‑controlled trial in Nature and Science of Sleep found modest sleep improvements in 155 adults (18‑65) taking 250 mg of magnesium bisglycinate daily for four weeks. A 2024 Cureus review of multiple magnesium trials concluded that the data are too heterogeneous to draw a strong overall conclusion.
Both experts agreed that magnesium may help individuals who are deficient or whose sleep is affected by muscle tension, while melatonin is better suited for circadian‑related difficulties. Neither supplement is a universal solution, and underlying causes such as stress, sleep apnea, restless legs, medications or hormonal changes should be considered.
Safety considerations were highlighted: melatonin’s effectiveness depends on timing and dose and can cause next‑day drowsiness, headache, dizziness or medication interactions; magnesium can cause gastrointestinal upset, diarrhea, nausea, abdominal cramping, and should be used cautiously in people with impaired kidney function. Both experts emphasized that supplements should complement, not replace, good sleep hygiene practices. The available evidence for magnesium as a general sleep aid remains limited and mixed.