Solaray Guaranteed Potency L-5-Hydroxy Tryptophan is a combination of natural L-5-hydroxytryptophan (L-5-HTP), Vitamins B-6 and C, and bioflavonoids. Tryptophan is enterically coated to enable the capsules to bypass enzymes in the stomach which would convert L-5-HTP to serotonin prematurely (before reaching the central nervous system). The L-5-HTP in Solaray Guaranteed Potency L-5-Hydroxy Tryptophan is a natural extract of the Griffonia bean, not produced synthetically or by a fermentation process.