Natural Short Sleepers are defined as individuals who sleep fewer than 6 hours per night without any impact on health or daytime mental fatigue levels. Emerging evidence suggests that, in the general population, the gut microbiota would be negatively influenced by this sleep duration. It is possible that Natural Short Sleepers have a distinct gut microbiome. Identifying differences in microbiota composition may lead to an opportunity to improve health outcomes in those with inadequate or poor sleep.

Inclusion:

1. Men between 20 - 50 years of age and pre-menopausal women between 20 - 45 years of age (inclusive).
2. Consistent schedule during daytime hours.
3. Body Mass Index (BMI) 18.5 - 35 kg/m2 (inclusive).
4. Good physical and mental health as established by self-reported medical history and evaluated by a study investigator.
5. Willingness to maintain and record their general habits, eating, and daily activity/exercise pattern for the study period.
6. Willingness to maintain typical sleep hygiene patterns (e.g. sleep location, temperature, environment).
7. Willingness to maintain their current pattern of alcohol consumption for the duration of the study.
8. Willing and able to participate fully in all aspects of the study and complete all study procedures, including providing signed informed consent.
9. Willing and able to attend two in-person visits at a trial site
10. Completes all required procedures (screening questionnaire and ePROs) during the 14-day screening period 10a. Two instances of the sleep diary and Karolinska Sleepiness Scale may be missed by the participant without impacting eligibility
11. Has regular bowel habits, on at least 5 days a week.
12. Pittsburgh Sleep Quality Index (PSQI) score≤5 self-reported during the screening period.
13. Sleep, on average, 4-5.5 hours per night, verified via participant self-report during the screening period. If the participant's average is within the 4-5.5 hour range but slept more than 5.5 hours on any of the nights their eligibility will be assessed per PI/Sponsor discretion. Note: Oura ring data from the run-in period will be reviewed to confirm eligibility based on PI/Sponsor discretion.
14. Report feeling refreshed with no desire to nap during the daytime, with a score of ≤4 on the Epworth Sleepiness Scale (ESS) evaluated during the screening period.
15. Average KSS Score of 1-3 during the screening period.

Exclusion:

1. Ever diagnosed with or self-reports a sleep disorder, including sleep apnea, habitual snoring (defined as loud, persistent snoring 3 or more nights per week), insomnia, narcolepsy, or parasomnias.
2. Extreme chronotypes, those who regularly go to sleep prior to 8:00pm.
3. Any current diagnosed or self-reported gastrointestinal disorder, including Crohn's disease, ulcerative colitis, celiac disease, IBS, or functional bowel disorder or chronic heartburn.
4. Regularly wakes up during the night 5 or more times per night for a cumulative amount of 30 minutes as observed via self-report during the screening period, per PI discretion.
5. Currently taking medications (including over-the-counter medications) or dietary supplements that, in the investigator's opinion, may affect the participants' microbiome or sleep.
6. Have taken in the last 3 months medications (including over-the-counter medications) or dietary supplements that, in the investigator's opinion, may affect the participants' microbiome or sleep.
7. Neurodegenerative diseases (including multiple sclerosis, Parkinson's disease, Alzheimer's disease, dementia).
8. Recent history (past year) of alcohol abuse or dependence. Defined as regularly drinking more than 12 drinks for females and more than 20 drinks for males per week and based on PI discretion.
9. Drug abuse or dependence, including consistent recreational substance use such as marijuana.
10. Binge drinking behavior, defined as 4 or more alcoholic drinks for women or 5 or more alcoholic drinks for men in one sitting on 2 or more occasions, within the past 1 month with final decision per PI discretion.
11. Recent history (current use or within the past 1 month) of smoking, vaping or other use of nicotine-containing products.
12. Diagnosed neuropsychiatric disorders or symptoms possibly affecting sleep e.g. (generalized anxiety disorder (GAD), major depressive disorder (MDD), bipolar disorder, schizophrenia)
13. Any use of systemic antibiotics in the past 3 months. This does not include topical or targeted antibiotic use (ointment, spray, eye drop, ear drop).
14. Any use of probiotic supplements in the past 2 weeks.
15. Any use of proton pump inhibitors (PPIs) in the past 2 weeks.
16. Any use of laxatives or antidiarrheals in the past 4 weeks.
17. Any use of non-steroidal anti-inflammatory drugs (NSAIDs) for 5 or more consecutive days in the past 4 weeks.
18. Pregnant or breastfeeding or planning to become pregnant.
19. Personal circumstances affecting stress or sleep (e.g. serving as a caretaker/required to wake up during sleep/major change in personal life). Note: Life situations causing stress or challenges in sleep that are considered shortterm, per PI discretion, may be considered for re-screening 4 weeks after the life situation has resolved, meaning it is no longer causing stress or challenges in sleep.
20. Planned overnight travel during the study.
21. Females experiencing perimenopausal or menopausal symptoms, or those who have been diagnosed as perimenopausal or menopausal by a physician.
22. Any diagnosed condition or undiagnosed symptom which disrupts sleep, including, but not limited to, hyperthyroidism, night sweats, restless legs, or poorly controlled allergic rhinitis.
23. Varying work schedule and/or shift workers who work overnight shifts (e.g. 3rd shift, working late night to early morning hours).
24. Any other personal or medical condition that the investigator believes may bias or confound the results.

Natural Short Sleepers are defined as individuals who sleep between 4 and 5.5 hours per night without any impact on health or daytime mental fatigue levels.