Magnesium
Magnesium is an essential mineral and electrolyte that acts as a cofactor for hundreds of enzymes. It contributes to energy metabolism, protein and DNA synthesis, nerve signaling, muscle contraction and relaxation, heart rhythm, and bone metabolism. This broad role does not mean that extra magnesium automatically improves all of those functions.
The DGE magnesium reference values estimate an adequate intake of 350 milligrams per day for adult men and 300 milligrams for adult women. The values cover total intake from food and drinks; they are not a supplement dose. Whole grains, legumes, nuts, seeds, green leafy vegetables, fish, and seafood are useful sources, while potatoes, bananas, meat, and dairy can contribute through the amounts commonly eaten.
In healthy people with typical eating patterns, clinically meaningful deficiency is uncommon. Risk can rise with prolonged gastrointestinal losses, impaired absorption, certain kidney or endocrine conditions, alcohol misuse, or medicines that increase loss. Cramps, twitches, poor sleep, or fatigue are not specific to magnesium and should not be treated as a diagnosis. Blood magnesium may be useful in clinical context, but interpretation belongs with the overall history and other findings.
For strength training, sufficient intake of minerals supports normal physiology; magnesium above adequacy is not established as a general recovery, sleep, or performance enhancer. Sweat contains magnesium, but far less than sodium and chloride, so a sweaty workout alone does not prove the need for a high-dose electrolyte or magnesium product. Combination products such as ZMA also count toward the total from every supplement.
Magnesium from food is not normally the cause of toxicity in healthy kidneys. Concentrated supplemental magnesium can cause diarrhea, nausea, and cramping; very high exposure can be dangerous, especially when kidney function is impaired. It can reduce absorption of tetracycline or quinolone antibiotics and oral bisphosphonates if taken too close together. The NIH magnesium fact sheet details these interactions. Use supplements to address a specific intake gap or professional recommendation, and check the label for elemental magnesium rather than comparing the total weight of different compounds.