Cognitive Health: 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 emotional well-being, 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 isn't just our process or what goes into our supplements -- what we leave out matters, too. All Pure Encapsulations products are FREE FROM many common allergens like wheat, eggs, tree nuts & peanuts, gluten, artificial colors, flavors & sweeteners, coatings and shellacs, GMOs, unnecessary binders, fillers & preservatives, and more.