Please note that this section reports on claims that have not yet been substantiated
Phenylalanine may improve memory and learning ability. It may also enhance mood and
alertness. It’s also said to help treat some types of depression. It’s also been used
to help treat schizophrenia and Parkinson's disease.
Phenylalanine tends to decrease appetite. It’s been used to treat obesity.
It’s also claimed to boost pain tolerance in premenstrual syndrome (PMS) and migraine
Phenylalanine has been taken off of the market in the U.S. The U.S. Food and Drug
Administration (FDA) says that the supplement may be harmful.
Side effects, toxicity, and interactions
High levels of phenylalanine are linked with the genetic issue phenylketonuria. In
infants with this issue, high levels of phenylalanine cause intellectual problems.
It can also lead to seizures and delays in development.
Pregnant women with the condition who don’t stay on a phenylalanine-free diet during
pregnancy may give birth to a baby with signs of phenylketonuria.
Women who are pregnant or breastfeeding shouldn’t use phenylalanine supplements.
People who have phenylketonuria, melanoma (pigmented type), or tyrosinemia (type I
and II) shouldn’t take phenylalanine.
You also shouldn’t take it if you take monoamine oxidase inhibitors (MAOIs).