Nootropics are substances that improve cognitive performance. They can increase learning ability, memory, and attention. Some nootropics can also help improve mood and reduce stress, directly influencing sleep.
Nootropics help sleep because they increase acetylcholine neurotransmission - a neurotransmitter responsible for memory, learning, and important for sleep regulation - helping with insomnia and obstructive apnea. In addition, some nootropics can help treat depression and anxiety, indirectly aiding in the quality and duration of sleep.