There is limited but mixed evidence on the effectiveness of bergamot essential oil (BEO) aromatherapy for sleep quality.
The study of postpartum women in Taiwan discussed in the FAQ:Is bergamot oil beneficial for peripartum depression? also measured sleep quality and found no significant difference in postpartum sleep quality between the women who received BEO aromatherapy and those who didn’t.[1]
However, a 2024 RCT of patients in a surgical intensive care unit found that the participants who received bergamot oil aromatherapy at night, as well as the participants who received lavender oil aromatherapy at night, experienced better sleep quality than the participants who received no aromatherapy.[2] Similarly, a small 2023 RCT of university students in Japan who inhaled BEO or placebo aromatherapy at bedtime and upon waking for a week found that the participants who had had aromatherapy reported slight but statistically significant improvements in some subitems (sleepiness on rising, feeling refreshed on rising, and duration of sleep) on a standardized scale of sleep quality after using BEO compared to the participants who had had the placebo;[3] however, no improvement over the placebo was seen in the other subscales, and it’s not clear whether there was any significant difference in scores on the full scale, so it’s difficult to draw a firm conclusion from this study.
In both of the above studies, the aromatherapy was delivered at night, in contrast to the Taiwanese postpartum study, whose participants had 15 minutes of aromatherapy during the day. This suggests that if bergamot aromatherapy does improve sleep quality, the timing may be important. More research is needed.