Support neurotransmitter and brain health with D, L-Phenylalanine. Studies show that supplementing with phenylalanine can help promote healthy mood. In the body, phenylalanine helps create neurotransmitters like dopamine, norepinephrine and epinephrine. Replenishing these neurotransmitters supports brain health, cognitive function, healthy mood and sleep. In the body, phenylalanine also supports norepinephrine production. Norepinephrine helps protect brain cells and supports healthy neuronal growth.