Dietary Supplement Hypoallergenic Zen Sleep with P5P and 5-HTP Zen sleep includes the same amounts of GABA and L-Theanine as the best-selling 200 mg of Zen, augmented with vitamin B6 as P5P, and 5-HTP, the precursor to serotonin and melatonin. The combination helps promote a relaxed state, and provides the necessary factors for the body to produce melatonin, supporting normal, healthy sleep.