Doctor's Best 5-htp (5-hydroxy L-tryptophan) contains a naturally occurring metabolite of the amino acid tryptophan. 5-htp is extracted from the seeds of the Griffonia simplicifolia plant. 5-htp is converted in the brain to serotonin, a neurotransmitter substance found at the junctions (synapses) between neurons. It produces a calming and relaxing effect providing support to help maintain mental, emotional well-being, and to promote healthy sleep.