Dietary Supplement. I-5 Hydroxytryptophan with vitamin B6 & vitamin C. Natural griffonia bean extract. Precursor to serotonin. Enteric coated; gentle on the stomach; easy-to-swallow tablets. I-5 Hydroxytryptophan is a mood and appetite regulating neurotransmitter produced within the body. Nature's Way uses natural I-5 HTP extracted from Griffonia simplicifolia beans combined with vitamin C, and vitamin B6. Contains no yeast, milk, lactose, wheat or soy.