Since amino acids obtained from dietary sources are the precursors of mood-regulating neurotransmitters such as serotonin and dopamine Christopher Tanev Canucks Jersey , amino acids are considered to hold potential in treatingdepression. Neurotransmitter precursors are the subject of ongoing research.So why is this topic relevant to primary care medicine? Patients have taken matters into their ownhands. Patients are self-treating their depression with amino acid supplements and appear to be motivated by a perceived benefi t in their mood and overall health. The amino acid precursors tryptophan,tyrosine, 5-hydroxytryptophan, and L-dopa are readily available as supplements at doses that exceed feasible dietary intake. Amino acids supplements have less potential for harm and larger therapeuticeffect when their use is physician-guided.This chapter presents the bundle damage theory of depression to probe the biologic basis of amino acid therapy. It offers primary care physicians a treatment protocol that implements laboratory testing toguide dosing; explains the potential side effects and how these can be minimized; offers quality regulation in product selection; and presents a protocol for simultaneous use of medication and nutrients inthe treatment of clinical depression.II. EPIDEMIOLOGYDepression is a global problem. The World Health Organization notes:32 Nearly 5