L-threonate is an endogenous compound found in cerebrospinal fluid and is derived from the metabolic breakdown of vitamin C. Its primary role in magnesium L-threonate is to facilitate the transport of magnesium across the blood-brain barrier. While magnesium L-threonate delivers elemental magnesium into the brain, the L-threonate component itself is crucial for this specific brain delivery. Some studies indicate that L-threonate plays an essential role in this delivery. There is no clear indication in the provided information that L-threonate has significant independent therapeutic effects beyond its role as a magnesium carrier for brain delivery.