Which amino acids? Leucine, Phenylalanine and Lysine
Amino LP7 is mainly composed of Leu, Phe, and Lys, which are potential substrates for synthesizing Glu in brain cells ( 35 ). Glu is known to be an important neurotransmitter that triggers de novo spine growth ( 36 ) and is involved in learning and memory ability ( 37 ). As the constituents of Amino LP7 have high rates of influx to the brain ( 22 ) via specific transporters (e.g., LAT-1), it is plausible that Amino LP7 not only delivered the neurotransmitter substrate into the brain but also competitively inhibited the blood-to-brain transfer of toxic amino acid metabolites, such as kynurenine, which share the same transporters
https://www.science.org/doi/10.1126/sciadv.abd5046
Interesting, there are multiple papers on kynurenine and schizophrenia too.