Nature's Way 5-HTP is actually a 5-HTP formula as it includes both vitamin C and B6 along with the 5-HTP ingredient. What is 5-HTP? 5-HTP is an herbal supplement, derived from the herb Griffonia simplicifolia. In the body, 5-HTP (5-hydroxytryptophan) gets converted to the neurotransmitter serotonin (Nature's Way has included B6 and vitamin C in the formula since these are necessary for the conversion). Serotonin has an enormous influence on how we feel physically and mentally, but since serotonin can't be supplemented directly, people have used 5-HTP for help with a wide range of conditions related to low serotonin levels, primarily appetite regulation, poor mood, and poor sleep patterns.