DL-phenylalanine is used as a medical treatment, rather than the two separate forms of phenylalanine, because both are found to be effective under different circumstances and to treat different conditions, so they are combines to maximize the effectiveness of the amino acid.
Phenylalanine and its forms
Phenylalanine is an amino acid. Amino acids are sometimes referred to as ‘the building blocks of life’.
Phenylalanine belongs to a particular group of amino acids known as essential amino acids, which basically means that they are needed by the body to carry our its everyday functions, but that the body itself cannot manufacture them, so they must be obtained by dietary means.
The most common form of phenylalanine in nature is L-phenylalanine.
D-phenylalanine is a synthetic form of phenylalanine that mirrors its natural cousin, and DL-phenylalanine therefore is a combination of these two amino acids.
Phenylalanine is converted into tyrosine in the human body.
Tyrosine is needed for the manufacture of certain proteins, hormones and neurotransmitters, therefore phenylalanine deficiency can present with a variety of symptoms ranging from lethargy and tiredness to confusion and mental impairment.
Sometimes children are born without the ability to manufacture an enzyme crucial to the metabolizing of phenylalanine, a condition known as PKU.
Left untreated, PKU can cause serious and irreversible mental retardation.