Magnesium L-Threonate Supports Memory and Learning Promotes Brain Health Magnesium (Mg) is an essential mineral best known for its role in bone and nervous system function. Recent research has demonstrated that it is also critical for normal brain health and normal cognitive function by maintaining the density and stability of neuronal synapses. However, most forms of Mg are not easily absorbed into the nervous system. Magtein is a patented form of Mg that readily crosses the blood-brain barrier for utilization in the brain. Laboratory studies indicate that Magtein supports brain health and may facilitate learning and memory, as well as a relaxed mood.