What Is DL Phenylalanine?

Phenylalanine, which is an alpha (essential) amino acid, is found in both naturally occurring (L-phenylalanine) and artificially synthesized (D-phenylalanine) forms. The two different forms of phenylalanine have different medical applications, and the derived DL form has the properties of both, and is, as such, used in the treatment of a number of conditions. As with all phenylalanine, DL-phenylalanine should not be consumed by people with phenylketonuria, a disease which causes the body to be unable to use phenylalanine.

Features

Phenylalanine is an essential amino acid, meaning it is needed by the human body but is not produced by it. Phenylalanine can be found, naturally, in high-protein foods; L-phenylalanine is also found as a component of aspartame, an artificial sweetener used in products like diet soda and sugar-free gum. L-phenylalanine is converted by the body into tyrosine, a non-essential amino acid (one that is produced by the body) that is used in the production of chemicals like proteins and hormones, including, according to the University of Maryland Medical center, the neurotransmitters dopamine and epinephrine. DL-phenylalanine is a combination of this form of phenylalanine; D phenylalanine does is not used in protein synthesis as is its natural form.

Function

DL-phenylalanine has been (and is still) studied as a substance with both analgesic (pain-relieving) and anti-depressant properties. A study from the Brampton Brain Clinic suggests that DL-phenylalanine improves the action of other painkillers by increasing activity in the endogenous analgesia system. Disabled World notes that DL-phenylalanine has been shown to be particularly effective in patients who suffer from chronic pain due to conditions like arthritis. Another study led by H. Beckmann demonstrated that DL-phenylalanine worked as well as another common treatment in the reduction of depression symptoms, which has been linked in other studies to its role in the production of neurotransmitters.

Benefits

Phenylalanine deficiency is linked to a number of symptoms, including, according to Disabled-World.com, confusion, lethargy, and memory problems. Returning the level of phenylalanine to normal should help correct these issues. DL-phenylalanine, in addition to strengthening effects of painkillers for chronic pain sufferers, has been shown, according to Disabled World, to alleviate a number of symptoms associated with Parkinson's disease, including related depression and impaired speech and gait.

Effects

DL-phenylalanine, as with other forms of phenylalanine, can negatively impact the health of people who suffer from phenylketonuria (PKU), a disease in which, instead of converting phenylalanine into the useful tyrosine, phenylalanine is converted into phenylpyruvate. Unchecked phenylketonuria can have severe neurological and other health effects, including mental retardation, so phenylketonurics are put on a low-protein, tyrosine-supplemented PKU diet.

Considerations

DL-phenylalanine should not be used by persons with phenylketonuria. Additionally, as with many other supplements, DL-phenylalanine is often sold with the warning: "These statements have not been evaluated by the FDA." An example of a misleading statement from a DL-phenylalanine company can be seen in the Resources below: the company claims that DL-phenylalanine is an essential acid, which is not strictly true: L-phenylalanine is as an essential acid, but the resulting DL form is not.