The study aims to evaluate the sub-chronic effects of colonic delivery of a post-biotic on stress response, mood state, sleep, and cognition in healthy young subjects with elevated self-reported stress levels. It is hypothesized that oral intake of the post-biotic, when released in the colonic intestinal site, leads to a blunted subjective and objective stress response after a stress induction.

Scientific findings over the past years suggest that certain bacteria in our gastrointestinal system have an influence on our mood, although, the mechanisms are not yet well understood. One of the possibilities is that bacteria produce compounds that interact with neurons in the gut. These neurons could subsequently send signals to the brain.

This study is a proof of principle study examining the effects of a post-biotic in the distal intestinal tract (terminal ileum, colon) on stress response, mood state, sleep, and cognition. The study is expected to provide key insights in the potential of treatment strategies aimed at stimulating the colonic enteric nervous system to exert mood enhancement. It is hypothesized that interactions with the local Enteric Nervous System leading to stress reduction, mood enhancement and sleep promotion effects. The study will employ an in-person clinic visit, in addition to traditional self-reported, behavioural, and physiological outcome measures; exploratory digital health outcomes will also be included to identify novel objective mood/stress measures.

This study seeks to recruit a total of 75 healthy males (25 in each arm), between the ages of 21-30 years old (inclusive) from local community outreach in Singapore over a period 12 months. This study is a hybrid study (partially decentralized).

The total duration of participation from each participant will be 9 days (excluding, the screening and enrolment days).

Inclusion Criteria:

• Aged 21 to 30 years
• Men
• Perceived Stress Scale (PSS-10) score >13
• Own and uses a smartphone that is capable to run the study applications with access to the internet
• Adequate fluency in the English language to understand the inform consent process, study instructions and study assessments
• Sufficient vision and hearing to complete study procedures
• Willing to commit to the study procedures
• Willing and able to participate and to give written informed consent All inclusion criteria will be assessed based on self-reported information during the screening visit.

Exclusion Criteria:

• Past (< 6 months prior to the study) or current major neurological, psychiatric, gastrointestinal, metabolic disease or cardiovascular disease
• Past (<1 months prior to the study) or current use of psychoactive medication, cardiovascular medication, or corticosteroids.
• Known medical history of hypotension or currently on antihypertensive medication
• Alcohol intake >1 units day
• Present or past history of alcohol or drug addiction and/or recreational drug use
• BMI <18.5 or >25 kg/m2
• Maltodextrin allergy
• Members of the research team or their immediate family members. An immediate family member is defined as spouse, parent, child, or sibling, whether biological or legally adopted All exclusion criteria will be assessed based on self-reported information during the screening call.