5-HTP (5-Hydroxytryptophan) is a drug-free and naturally occurring plant-derived amino acid that participates in the body’s synthesis of serotonin, the chemical messenger that plays a key role in enhancing mood. Natrol 5-HTP, the #1 5-HTP brand in America, promotes a calm and relaxed mood while helping you maintain a positive outlook. Promotes a calm and relaxed mood. Helps maintain a positive outlook. Enables production of Serotonin. 100% drug-free. Non-habit forming. Regular use of Natrol 5-HTP can help provide a more positive and balanced attitude needed to help you maintain a healthy outlook. Today is a good day to have a good day. Go ahead and uplift your mood with Natrol 5-HTP.