The scent of lavender has long been promoted as a sleep aid because of its reputed calming effects. Now, for the first time, its benefits have been demonstrated in a scientific study. Thirty-one healthy sleepers smelled either lavender oil or distilled water before bed on alternate nights in a sleep laboratory at Wesleyan University. When exposed to the lavender scent for a total of eight minutes, participants experienced deeper sleep during the first half of the night, according to readings by a machine that measures brain waves, and they felt more refreshed in the morning. Lead researcher Namni Goel speculates the effect of lavender may be even stronger for troubled sleepers or in instances of longer exposure, which could be achieved by putting drops of oil on a pillow. Essential oil is typically more potent than less-concentrated sources of lavender, such as candles, dried flowers, and room sprays, she adds.