Allergy Research Group, Zen Sleep with P5P and 5-HTP, 60 Vegetarian CapsulesDietary 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.