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Other name(s):

a-amino-b-phenyl-propionic acid

Unsubstantiated claims

Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.

Phenylalanine may help improve memory and learning ability, enhance mood and alertness, and help treat some types of depression.

It has been used to help treat schizophrenia and Parkinson's disease.

Phenylalanine tends to decrease appetite and has been used in treating obesity.

It has been purported to improve pain tolerance associated with pre-menstrual syndrome and migraine headaches.

Recommended intake

Phenylalanine has been withdrawn from the U.S. marketplace. The FDA has determined that supplemental phenylalanine may be harmful.

Side effects, toxicity, and interactions

Elevated serum levels of phenylalanine are associated with the genetic condition phenylketonuria. In infants with phenylketonuria, high levels of phenylalanine cause intellectual disability and can also lead to seizures and delays in general development.

Pregnant women with phenylketonuria who do not remain on a phenylalanine-free diet during pregnancy may deliver an infant with all the signs of phenylketonuria.

Women who are pregnant or breastfeeding should not use phenylalanine supplements.

People who have phenylketonuria, melanoma (pigmented type) or tyrosinemia (type I and II) should not take phenylalanine.

Phenylalanine should not be taken in conjunction with antidepressants belonging to the class of monoamine oxidase (MAO) inhibitors.

Additional information

Click here for a list of reputable websites with general information on nutrition.

Online Medical Reviewer: Wilkins, Joanna, R.D., C.D.
Last Review Date: 1/21/2013