Lerner, a dermatologist who isolated melatonin (MLT) in 1959, was the first to report on its hypnotic properties, and was also the first to self-administer this hormone. Later, in 1971, Anton-Tay and coworkers injected MLT into volunteers who quickly fell asleep. In adults, MLT treatment appears to have beneficial effects in those who have sleep disorders due to delayed sleep onset, shift work, and jet lag. MLT can enhance adaptation to forced phase shift in simulated shift-work and jet-lag conditions. However, better controlled, long-term studies are still required. MLT may also benefit certain types of adult insomnia.