Neurobiome-Directed Interventions (NDIs): The Science of Gut-Brain Probiotics, and Why Flore Builds Them

Neurobiome-Directed Interventions (NDIs): How Gut Bacteria Support Mood, Stress, and Focus

What are neurobiome-directed interventions?

An NDI is a probiotic-and-prebiotic formula chosen for its gut–brain effects and matched to your gut data. It builds on psychobiotics, which the scientific literature defines as “live bacteria (probiotics) which, when ingested, confer mental health benefits through interactions with commensal gut bacteria,” and researchers later widened the definition to include prebiotics — the fibers that feed those bacteria (Sarkar et al., Trends in Neurosciences, 2016). It is one of the fastest-growing ideas in microbiome science, and it rests on a simple observation: the gut and the brain talk to each other, and the microbes in between shape the conversation.

How NDIs work: the gut–brain axis

The gut and brain are in constant two-way conversation along the gut–brain axis, defined in one widely cited review as “bidirectional communication between the central and the enteric nervous system” (Carabotti et al., Annals of Gastroenterology, 2015). Your gut bacteria join that conversation through several routes:

• Serotonin. About 95% of the body's serotonin is stored in the gut — in enterochromaffin cells and enteric neurons — and only 5% in the brain (Martin et al., Cell Mol Gastroenterol Hepatol, 2018). See where the gut makes serotonin.
• Neurotransmitters. Gut bacteria make signaling molecules that act on the nervous system, including “GABA by the Bifidobacteria family” and “GABA and acetylcholine by the Lactobacilli family” (Sarkar et al., 2016).
• The vagus nerve. A direct line that “transmits information from the luminal environment to CNS” (Carabotti et al., 2015). See how the vagus nerve works.
• Short-chain fatty acids. Made when bacteria ferment fiber, these are “able to stimulate… mucosal serotonin release” and influence the brain (Carabotti et al., 2015).

Because every one of these routes is microbial, which bacteria you carry — and which are missing — changes what an NDI can actually do for you. That is the gap a generic blend leaves open. Read more on how gut health affects mental health and the gut–brain axis explained.

Why NDIs are personal: directed by your data

Classic gut–brain probiotic research tests one strain, or one blend, across a whole population. It answers “can gut bacteria affect the mind?” — yes — but not “what does your gut–brain axis need?” A neurobiome-directed intervention is Flore’s answer to that second question: gut–brain science made personal.

The target is your neurobiome — the community of gut organisms that most influence the gut–brain axis. Instead of a fixed blend, an accredited lab analyzes your stool sample, Flore reads which neuroactive organisms and pathways you carry, and builds a synbiotic — probiotic strains plus prebiotics — matched to what your data shows. The gut–brain axis is the science. An NDI is that science aimed at your own data.

Neurobiome-directed intervention (NDI) is Flore’s term for this approach — not an established, peer-reviewed classification. What is peer-reviewed is the underlying gut–brain science and Flore's own precision-synbiotic work: a 2024 pilot open-label study in autism spectrum disorder, published in mSystems.

What the evidence actually says

Controlled trials of specific strains show small but real effects. In one randomized, placebo-controlled trial of 45 healthy adults, six weeks of a Bifidobacterium longum strain (NCC3001) cut perceived stress by 21.4% against placebo (Boehme et al., Nutrients, 2023). Effects like this are strain-specific, which is the whole point — the right strain for one person is not the right strain for the next.

Flore's own contribution is a 2024 pilot open-label study in autism spectrum disorder, published in mSystems (Phan et al., Arizona State University and Sun Genomics), which found precision synbiotics increased gut microbiome diversity and reduced GI discomfort (Phan et al., mSystems, 2024). The authors are clear that it is an open-label study without a placebo group — an early signal, not a randomized controlled trial. Across 18,392 people served, about 95% never requested a reformulation, and in a paired analysis of 651 people, 47.4% reported within-subject symptom resolution. Those are honest, labeled figures — observational and self-reported, not clinical cure rates.

Getting started with Flore

The front door is inexpensive on purpose. Start with a single-strain gut-brain synbiotic from GoodOnes™ — The Bright One for everyday mood, or The Calm One for everyday focus and calm — each $49 (Subscribe & Save $44.10). When you want the precise version, an accredited lab analyzes your gut microbiome test and Flore builds a formula from what is actually there: up to 68 curated strains plus 40+ prebiotics, matched to your results and refined against more than 40,000 formulations.

Want the precise version instead of a guess?
A gut microbiome test is the front door. Flore reads your gut and builds a formula matched to your own results.
Test your gut & personalize your probiotic →

Frequently asked questions

Are NDIs the same as probiotics?
Every NDI is built from probiotics and the prebiotics that feed them, but the term means a formula chosen for gut–brain effects on mood, stress, and focus and matched to your own gut data.

Is an NDI the same as a psychobiotic?
Psychobiotics is the established research term for the field. A neurobiome-directed intervention is Flore's term for making that science precise — a synbiotic matched to your own sequenced microbiome rather than a one-size-fits-all blend.

Do NDIs really work for anxiety or mood?
Controlled trials show small but real effects on stress and mood measures, and the effects are strain-specific. That is exactly why Flore matches strains to your gut data. This supports mood and gut health and is not a treatment for any diagnosed condition.

How do I try Flore's approach?
Start with a $49 GoodOnes™ gut-brain synbiotic (The Bright One or The Calm One), or take a gut microbiome test for a formula matched to your own results.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is educational and is not medical advice; if low mood, anxiety, focus, or sleep is persistent or affecting your daily life, please talk to a qualified healthcare provider.