Magnesium

What magnesium is

Magnesium is an essential mineral your body uses in more than 300 enzymatic reactions — including nerve signaling, muscle relaxation, and the regulation of neurotransmitters like GABA that calm the nervous system. Because of that calming role, it's become one of the most popular sleep-related supplements.

Many adults get less than the recommended amount of magnesium from diet alone. Food sources include leafy greens, nuts, seeds, legumes, and whole grains.

What the evidence says

The evidence is promising but not definitive. Some small trials — particularly in older adults with insomnia — show modest improvements in how quickly people fall asleep and their sleep quality. Larger, higher-quality studies are still needed, and results are mixed.

Forms and timing

Not all forms absorb equally. Magnesium glycinate and citrate are commonly preferred for sleep because they're well-absorbed and gentler on digestion; magnesium oxide is cheap but poorly absorbed and more likely to cause loose stools. If used for sleep, it's typically taken one to two hours before bed.

Safety and limits

Magnesium from food is safe. From supplements, high doses can cause digestive upset and diarrhea, and people with kidney problems should be especially cautious. It can also interact with certain medications.