5-hydroxytryptophan and l-tyrosine are key precursors for the synthesis of several neurotransmitters responsible for a healthy emotional outlook, including serotonin, dopamine, epinephrine and norepinephrine. These neurotransmitters are involved in the regulation of endocrine and brain activity in addition to sleep/wake cycles. Research suggests that l-tyrosine may also support cognitive function and memory under stressful conditions. A healthy level of the inhibitory neurotransmitter GABA is also associated with positive mood. Research suggests that both GABA and l-theanine enhance alpha wave production in the brain, promoting relaxation. Complementary support for relaxation is provided by passionflower, while Rhodiola rosea supports cognitive and mental function under stressful conditions. Vitamin B6 is a cofactor that plays an important role in supporting positive emotional health.