Figure 1.

The three phases of urinary neurotransmitter excretion in response to amino acid dosing. The horizontal axis is not labeled with specific amounts; it reflects the general trend seen in the population. Amino acid dosing needs are highly individualized. The dosing level needed to inflect into the next level varies greatly throughout the general population. For example, some patients inflect into phase 3 on 37.5 mg of 5-HTP per day, while others need as high as 3,000 mg per day (source: DBS Labs database).