Natural Factors Tranquil Sleep is a safe, fast acting formula containing: the amino acid 5-HTP; the hormone melatonin; and green tea's stress-reliever, L-theanine. Together these natural compounds exert a powerful synergistic effect to promote restful sleep. Now in a higher potency formula making it a great non-habit-forming aid for anyone who suffers from poor sleep quality or has difficulty falling asleep, whether from jet lag, shift work, or sleep disorders.