DLPA is a mixture of two forms of the essential amino acid phenylalanine, the naturally occurring L-phenylalanine and the synthetic D-phenylalanine with nootropic effects. DLPA enhances mood and can increases alertness and improve memory and learning.
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 Hill RA, et al (1997). Structure–activity studies for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid receptors: acidic hydroxyphenylalanines. J Med Chem, 40(20):3182-91. doi: 10.1021/jm950028z