Brief
Hinoki root oil linked to fewer night awakenings in Japanese women study
Researchers report that inhaling Hinoki root oil for ten seconds each night lowered night‑time awakenings and boosted morning recovery.
By Felo News Desk · Published
In a two‑week crossover trial, twelve Japanese women aged 35 to 60 who inhaled three drops of Hinoki (Japanese cypress) root essential oil each night reported fewer awakenings and felt more recovered in the morning, according to a study published on September 1, 2026 in the Journal of Wood Science.
What happened
Participants placed three drops of the oil in a paper cup, breathed the scent for ten seconds, then kept the cup about 30 cm from their noses while they slept. Each woman experienced a two‑week period with the oil and a two‑week period with an unscented control, the order being randomized and single‑blind. Sleep was monitored via a headband recording brain waves, a smartwatch tracking movement, and daily questionnaires.
What the reports add
The study found that by day 13 of oil use, participants reported less sleepiness after waking and greater fatigue recovery compared with the control phase. Smartwatch data showed a reduction in the number of nocturnal awakenings. Brain‑wave analysis revealed increased delta activity after seven days of exposure, a pattern associated with deeper sleep.
What was said
"We wanted to address two questions: whether essential oil production could add value to underused Hinoki roots and whether that oil could improve sleep," Associate Professor Kuniyoshi Shimizu of Kyushu University's Faculty of Agriculture told ScienceDaily.
How it came about
Hinoki trees are a major timber source in Japan, but their roots are typically discarded after logging. Prior research examined oils from leaves and branches, but the roots have received little attention. Shimizu’s team designed the home‑based trial to assess whether repeated exposure to the root aroma could influence sleep quality in everyday settings.
Key facts
- The trial involved 12 Japanese women aged 35‑60 using Hinoki root oil for two weeks. (sciencedaily.com)
- Participants inhaled three drops of oil for ten seconds before sleeping. (sciencedaily.com)
- By day 13, users reported fewer awakenings and better morning recovery. (sciencedaily.com)
- Smartwatch data showed fewer night awakenings during oil use. (sciencedaily.com)
- Brain‑wave recordings indicated increased delta activity after seven days. (sciencedaily.com)
Sources
- [1] sciencedaily.com — originally reported as “A few drops of this Japanese tree oil may help you sleep more soundly”
