5-HTP 100 mg (On Back Order with Manufacturer)Item Description Promotes brain serotonin levels to support emotional well being, healthy eating behavior, and healthy sleep*. 5 Hydroxytryptophan (5 HTP) is an intermediate in the natural synthesis of the essential amino acid, tryptophan, to serotonin. The enzyme tryptophan hydroxylase adds a hydroxyl group (OH) to tryptophan, forming the 5 HTP intermediate. In the body, it converts to serotonin with the removal of a carboxyl group (COOH) by a second