Life Extension D, L-Phenylalanine Capsules, 500 mg, 100 vegetarian capsules

Phenylalanine is an essential amino acid that can be converted to L-tyrosine in the liver. Tyrosine is used in the nervous system to make a class of neurotransmitters called catecholamines: dopamine, norepinephrine and epinephrine. Epinephrine, made from tyrosine in the adrenal medulla, functions as a neurohormone and is known as adrenaline.¹

In addition to acting as a neurotransmitter that supports healthy mood and sleep, norepinephrine is now known to protect brain cells by promoting a healthy inflammatory response, inhibiting oxidative stress and supporting healthy neuronal growth and connectivity.²

Dopamine, though long associated with more primal aspects of brain function linking behaviors to rewards, is recognized now as a mediator of higher-order cognitive capacities.^3,4 The diminishment in brain catecholamine production that occurs with aging may be a contributing factor in normal age-related cognitive decline.^3,5 Providing catecholamine precursors can help support healthy cognitive function.⁶ The enzyme that catalyzes the conversion of tyrosine to dopamine may work more efficiently if its co-factors (vitamins B6 and C) are included.^7,8

Phenylalanine supplementation supports healthy neurotransmitter synthesis and clinical trials suggest it may promote positive moods.^9,10

Since both norepinephrine and epinephrine can cause smooth muscle (arterial) contraction, care with blood pressure should be taken when supplementing with phenylalanine.

D,L-phenylalanine is a 50/50 mixture of its two stereoisomers.