UMIN-ICDS Clinical Trial

Public title

A study of konjac extract intake and sleep

Acronym

Konjac Sleep Study

Scientific Title

Effects of konjac extract intake on sleep

Scientific Title:Acronym

KONSLEEP

Region

Japan

Condition

Healthy adults with sleep dissatisfaction

Classification by specialty

Adult

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

To examine the effects of 6-week daily intake of a konjac-derived extract containing phospholipids and ceramides on sleep architecture (sleep stages assessed by simplified polysomnography) and subjective sleep in middle-aged adults with sleep dissatisfaction.

Basic objectives2

Efficacy

Basic objectives -Others

Trial characteristics_1

Exploratory

Trial characteristics_2

Developmental phase

Not applicable

Primary outcomes

Proportion and duration of each sleep stage (wake, light NREM, deep NREM, and REM sleep) assessed by simplified polysomnography (EEG/EOG), compared between the 2-week baseline period and weeks 5-6 of supplementation.

Key secondary outcomes

1. Total sleep time and sleep efficiency by actigraphy (daily)
2. Five factor scores of the OSA sleep inventory MA version, and presence of dreams and nightmares (every morning)
3. Pittsburgh Sleep Quality Index (PSQI) (weekly)
4. Epworth Sleepiness Scale (ESS) (weekly)
5. Japanese version of the Profile of Mood States (POMS) (weekly)
6. Cornell Medical Index (CMI) health questionnaire (weeks 1, 4, and 8)
7. Skin condition questionnaire (weekly)
8. Skin moisture measured with a skin checker (every morning)

Study type

Interventional

Basic design

Cross-over

Randomization

Non-randomized

Randomization unit

Blinding

Double blind -all involved are blinded

Control

Placebo

Stratification

Dynamic allocation

Institution consideration

Blocking

Concealment

No. of arms

2

Purpose of intervention

Prevention

Type of intervention

Food

Interventions/Control_1

Test food (6 weeks) => washout period (3-5 months) => control food (6 weeks).
Each supplementation period is preceded by a 2-week baseline period without supplementation. Dose: one capsule per day, taken in the morning.
Test food: capsules containing a konjac-derived extract with phospholipids and ceramides.
Control food: capsules indistinguishable in appearance from the test food.

Interventions/Control_2

Control food (6 weeks) => washout period (3-5 months) => test food (6 weeks).
The baseline period, dose, and foods are the same as in Intervention 1.

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

40

years-old

<=

Age-upper limit

60

years-old

>=

Gender

Male and Female

Key inclusion criteria

Generally healthy men and women aged 40-60 years who are dissatisfied with their sleep, defined as meeting at least one of the following: (1) taking a long time to fall asleep, (2) waking up too early in the morning, (3) occasionally waking up during the night, or (4) lacking a sense of deep sleep upon waking. Eligibility is confirmed by a 1-week screening (actigraphy, questionnaires, and a simplified polygraph recording).

Key exclusion criteria

1. Individuals with a psychiatric disorder
2. Individuals receiving treatment for insomnia
3. Individuals with sleep apnea syndrome
4. Individuals who habitually take naps
5. Individuals who share a bedroom with family members
6. Smokers
7. Individuals with an irregular daily routine
8. Individuals who habitually drink heavily
9. Individuals who work at night
10. Individuals planning to travel across time zones (e.g., overseas travel) during the study period
11. Individuals taking sleeping pills
12. Individuals taking medication on a regular basis
13. Individuals taking supplements intended to improve sleep who are unable to discontinue them during the study period
14. Individuals with sensitive skin
15. Individuals with food allergies
16. Individuals unable to participate in two 8-week study periods

Target sample size

12

Name of lead principal investigator

1st name	Akihiro
Middle name
Last name	Karashima

Organization

Tohoku Institute of Technology

Division name

Department of Electrical and Electronic Engineering, Faculty of Engineering

Zip code

982-8577

Address

35-1 Yagiyama Kasumi-cho, Taihaku-ku, Sendai, Miyagi 982-8577, Japan

TEL

022-305-3213

Email

karashima@tohtech.ac.jp

Name of contact person

1st name	Akihiro
Middle name
Last name	Karashima

Organization

Tohoku Institute of Technology

Division name

Department of Electrical and Electronic Engineering, Faculty of Engineering

Zip code

982-8577

Address

35-1 Yagiyama Kasumi-cho, Taihaku-ku, Sendai, Miyagi 982-8577, Japan

TEL

0223053213

Homepage URL

Email

karashima@tohtech.ac.jp

Institute

Tohoku Institute of Technology

Institute

Department

Personal name

Organization

Daicel Corporation

Organization

Division

Category of Funding Organization

Profit organization

Nationality of Funding Organization

Co-sponsor

Sendai Shirayuri Women's College

Name of secondary funder(s)

Organization

Research Ethics Committee, Tohoku Institute of Technology

Address

35-1 Yagiyama Kasumi-cho, Taihaku-ku, Sendai, Miyagi 982-8577, Japan

Tel

022-305-3800

Email

rs-center@tohtech.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

東北工業大学（宮城県）、仙台白百合女子大学（宮城県）
Tohoku Institute of Technology (Miyagi), Sendai Shirayuri Women's College (Miyagi)

Date of disclosure of the study information

2026

Year

11

Month

01

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

13

Results

Results date posted

Results Delayed

Delay expected

Results Delay Reason

A manuscript reporting the results is being prepared for submission. The results will be posted once the paper has been accepted for publication.

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

No

IPD sharing Plan description

Individual participant data will not be shared.

Recruitment status

Completed

Date of protocol fixation

2022

Year

10

Month

28

Day

Date of IRB

2022

Year

10

Month

28

Day

Anticipated trial start date

2022

Year

12

Month

19

Day

Last follow-up date

2024

Year

09

Month

02

Day

Date of closure to data entry

Date trial data considered complete

Date analysis concluded

2024

Year

09

Month

12

Day

Other related information

This trial was registered retrospectively after data collection had been completed, because prospective registration was overlooked. Primary and secondary endpoints were not distinguished in advance; the primary outcome listed above was specified at registration as the measure representing the study objective (effects on sleep) stated in the protocol.
Participants were enrolled in six pairs at approximately two-month intervals. Within each pair, one participant took the test food first and the control food second, and the other took them in the reverse order (counterbalancing of order and season).
The correspondence between the food labels (A/B) and their contents was determined by the staff member who manufactured the test foods and who was not involved in data collection or analysis. The principal investigator, who assigned the intake order within each pair, was unaware of this correspondence. No random procedure was used at either step. The allocation key was disclosed only after all analyses had been completed.
36 individuals underwent screening, and 13 were enrolled in the main trial. One participant withdrew during the first period after starting night-shift work, which met an exclusion criterion, and was replaced by a newly enrolled participant. The 12 participants (six pairs) who completed the trial were included in the analysis.

Registered date

2026

Year

10

Month

07

Day

Last modified on

2026

Year

10

Month

16

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000072347