DL-Phenylalanine is a combination of the well-tolerated essential amino acids, d-phenylalanine and l-phenylalanine. Together, these compounds support positive outlook. l-Phenylalanine is a precursor to l-tyrosine, which converts to the neurotransmitters norepinephrine, epinephrine, dopamine and tyramine. l-Tyrosine and its metabolites may support memory and learning. d-Phenylalanine may promote the levels of certain endorphins, thereby calming stressed muscles and joints.* – DL-Phenylalanine is a combination of the well-tolerated essential amino acids, d-phenylalanine and l-phenylalanine. Together, these compounds help promote mental functioning and support positive outlook.* – Memory And Learning Support: l-Phenylalanine is a precursor to l-tyrosine, which converts to the neurotransmitters norepinephrine, epinephrine, dopamine and tyramine. l-Tyrosine and its metabolites may support memory and learning.* – Muscle/Joint Support: d-Phenylalanine may promote the levels of certain endorphins, thereby calming stressed muscles and joints.* – Pure Quality: Our supplements are made with only premium ingredients sourced from trusted suppliers and guided by our nutritional experts, then carefully manufactured and tested to verify their potency and purity. – Pure Difference: What makes us different isnt just our process or what goes into our supplements — what we leave out matters, too. Pure Encapsulations products are FREE FROM wheat, eggs, tree nuts & peanuts, gluten, artificial colors, flavors & sweeteners, coatings and shellacs, GMOs, and unnecessary binders, fillers & preservatives.