Effect of crocetin on quality of sleep: A randomized, double-blind, placebo-controlled, crossover study

•A RCT to evaluate the effects of crocetin on sleep architecture and subjective sleep parameters.•A daily intake of 7.5 mg of crocetin increased delta power.•Crocetin improved the subjective symptoms “sleepiness on rising” and “feeling refreshed,”•Crocetin supplementation could be useful as an alternative approach to improve sleep quality. The aim of the present study was to investigate the effect of crocetin on sleep architecture and subjective sleep parameters in healthy adult participants with mild sleep complaints. A randomized, double-blind, placebo-controlled, crossover study with two intervention periods of 14 days each, separated by a 14-day wash-out period. Thirty participants were randomly assigned to one of two sequence groups. Each group was given crocetin at 7.5 mg/day, or placebo. We measured objective sleep parameters using single-channel electroencephalography and assessed subjective sleep parameters using the Oguri–Shirakawa–Azumi Sleep Inventory, Middle-age and Aged version (OSA-MA). Differences between crocetin and placebo in an objective sleep parameter (delta power), and OSA-MA scores. Delta power was significantly increased with crocetin compared with placebo. There were no significant differences in the other sleep parameters, including sleep latency, sleep efficiency, total sleep time, and wake after sleep onset. Subjective scores for sleepiness on rising and feeling refreshed were significantly improved with crocetin compared with placebo. The findings of the present study suggest that crocetin supplementation contributes to sleep maintenance, leading to improved subjective sleep quality.