5-HTP Enhanced with Vitamins B6 and C vitamins and Herbs.

5-HTP Enhanced with Vitamins B6 and C

5-HTP (5-hydroxytryptophan) is a naturally-occurring metabolite 
of the essential amino acid tryptophan. 5-HTP for use in dietary 
supplements is derived from the seeds of the Griffonia 
simplicifolia plant. 
Metabolism and absorption of 5-HTP
5-HTP 
(5-hydroxytryptophan) is formed by the addition of a hydroxyl 
group (-OH) to the 5 carbon of the indole ring of tryptophan. 
Conversion of tryptophan to 5-hydroxytryptophan is catalyzed by 
the enzyme tryptophan hydroxylase.1 5-HTP functions as the 
precursor for serotonin, and is converted to serotonin in a 
pyridoxal phosphate (vitamin B6) dependent reaction catalyzed by 
the enzyme L-amino acid decarboxylase.2

Synthesis of 
serotonin in the brain requires an adequate supply of either 
tryptophan or 5-HTP as precursors. The supply of tryptophan 
available for conversion to 5-HTP depends on a number of 
factors, including nutritional status and competition between 
tryptophan and other amino acids for transport across the blood 
brain barrier.

Disturbances in the serotonin metabolic 
pathway may disrupt central nervous system functions which 
utilize serotonin as a neurotransmitter.2 Administration of 
5-HTP bypasses the conversion of tryptophan to 5-HTP. 5-HTP 
readily crosses the blood brain barrier and becomes available 
for serotonin synthesis. Serotonergic neurons (nerve cells 
stimulated by serotonin) regulate sleep, appetite, nociception 
(the perception of pain), and aggressive behavior.2

Serotonin 
is metabolized to 5-HIAA (5-hydroxyindolacetic acid) which is 
its primary breakdown product.3 The concentration of 5-HIAA in 
cerebrospinal fluid is used as an indicator of serotonin 
turnover in the CNS serotonin level. Psychiatric patients have 
been found to have low levels of 5-HIAA in the CNS fluid, 
suggesting serotonin deficiency.3

5-HTP is readily absorbed 
by the mucosal cells of the gastrointestinal tract. In one study 
using five subjects, systemic absorption of 5-HTP in combination 
with carbidopa averaged 69.2 percent.4 Another absorption study 
found that carbidopa enhanced the increase in serum 5-HTP 
concentration 5 to 15 fold.5 In this study, a single dose of 
5-HTP increased the plasma level of 5-HTP only slightly, whereas 
5-HIAA increased 9-20 fold. This suggests that the gut mucosa 
has a storage capacity for 5-HTP, and that plasma increases 
occur after maximum capacity is reached.5