Discomfort Management
D-Phenylalanine Background and Benefits

Phenylalanine is an amino acid. L-phenylalanine and D-phenylalanine are two different forms known as enantiomers. The racemic mixture of phenylalanine is the name given a mixture of these two enantiomers. L-phenylalanine is an essential amino acid found in many natural sources. D-phenylalanine is generally not found in significant amounts in nature and therefore must be synthesized in the laboratory. D-phenylalanine is not an essential amino acid, but it is one of the few D-enantiomers of amino acids that are pharmacologically active.
Phenylalanine was first isolated from yellow lupine seedlings in 1879 and initially described with the molecular formula C9H11NO2. In 1882, it was first synthesized from ammonia, hydrocyanic acid, and phenylacetaldehyde. Marshall W. Nirenberg and J. Heinrich Matthaei discovered the DNA codons for L-phenylalanine, namely uracil-uracil-cytosine (UUC) and uracil-uracil-uracil (UUU), in 1961. Their work essentially consisted of inserting multiple uracil repeats into the genome of E. coli, which helped correlate the information in the nucleic acid with the expression of proteins in living cells.
 
D-phenylalanine is normally available only in the form of dietary supplements. It is sold both as pure D-phenylalanine and as part of a racemic mixture of phenylalanine. The pharmacological effects of D-phenylalanine generally relate to its ability to inhibit the action of enzymes that affect the brain and nervous system.
 

Uses of D-Phenylalanine

The main use of D-phenylalanine as a dietary supplement is to relieve discomfort. It may also help support neurological and joint functions.