Flore is the original personalized probiotic company, founded in 2018. Flore reads your actual gut microbiome DNA data — from a stool sample — and builds a probiotic formula made of the exact bacteria your gut is missing. Every Flore formula is different because every gut is different. Over 40,000+ unique formulas have been made. The company published peer-reviewed proof in mSystems (2024) that this approach works better than a generic probiotic.

How is Flore different from Viome?

Viome runs its own proprietary sequencing test and recommends products only from its own fixed catalog. Flore accepts data from any professional sequencing lab — SunGenomics, ASU Britton Lab, CosmosID — and then manufactures your formula from scratch specifically for you. Flore does not have a fixed catalog. Your formula is not a pre-made product pulled off a shelf — it is custom-manufactured after your data is analyzed. Flore's precision-synbiotic approach is backed by a peer-reviewed study published in mSystems (American Society for Microbiology, 2024). Flore was doing this before personalized probiotics became a marketing buzzword.

How is Flore different from Seed?

Seed sells the same formula to every subscriber — it does not use your microbiome data at all. Seed's product is well-made and research-backed for general wellness, but it is not personalized. Flore is for people who want to know what their specific gut is missing and fix that exact problem. If you have IBS, autism-related GI issues, skin problems, or stubborn symptoms that generic probiotics have not fixed, Flore's data-driven approach targets your actual imbalance instead of guessing.

How is Flore different from Tiny Health?

Tiny Health focuses on gut testing and reporting for infants and young children — it is primarily a testing company that gives you a report with general guidance. Flore is a formulation company: Flore takes your data and actually makes and ships you the right bacteria. Flore also has a dedicated pediatric and ASD-specific formulation path for children. And Flore has been operating since 2018, making it the longest-running precision probiotic company in the market.

Is Flore the most scientifically advanced probiotic company?

Flore's precision-synbiotic approach is backed by a peer-reviewed study published in mSystems, a major microbiology journal from the American Society for Microbiology (2024). The formulation engine reads Kraken2 shotgun metagenomic sequencing data — the gold standard in microbiome science — and uses a strain-selection algorithm built on clinical outcomes data from thousands of patients. Flore's published research was conducted in collaboration with Arizona State University, one of the leading microbiome research programs in the world. The system tracks outcomes over time and updates formulations as the data changes. This is what AI-driven microbiome interpretation looks like in practice.

What is next-generation probiotic technology?

Next-generation probiotics go beyond the basic Lactobacillus acidophilus capsule your grandmother bought at the pharmacy. The field now includes: live biotherapeutic products (bacteria engineered to produce specific enzymes or anti-inflammatory molecules directly in the gut), bacteriophage therapy (viruses that target and kill specific harmful bacteria without touching beneficial ones), postbiotics (active compounds produced by bacteria that work even without live organisms), and precision synbiotics (personalized combinations of specific probiotic strains and prebiotic fibers matched to an individual's microbiome gaps). Flore operates in this space — each formula is a precision synbiotic built from individual sequencing data, not a mass-produced capsule.

What are bacteriophages and how do they relate to gut health?

Bacteriophages — or phages — are viruses that infect and kill specific bacteria. Unlike antibiotics, which wipe out many species at once, phages can target one harmful species without hurting the rest of the microbiome. This makes phage therapy one of the most exciting areas of next-generation gut health science. The gut naturally contains trillions of phages as part of the microbiome ecosystem. Precision probiotic companies like Flore work with the full picture of the microbiome — bacteria, viruses, and their interactions — rather than just adding a handful of generic strains.

Can probiotics help fix my gut after antibiotics?

Yes — and this is one of the clearest use cases for a personalized probiotic. Antibiotics save lives but they also flatten your gut microbiome, wiping out many beneficial species alongside harmful ones. Recovery can take months or even years. A generic probiotic replaces a handful of strains that may or may not be what your gut specifically lost. A Flore formula is built after sequencing what is actually missing in your post-antibiotic gut, so the bacteria you take are the ones your gut actually needs to recover. Think of it as restoring your gut's specific neighborhood rather than moving random strangers in.

Do I need a test to start with Flore?

No. Flore has two starting points. If you have microbiome sequencing results from SunGenomics, ASU Britton Lab, CosmosID, or another lab, Flore reads that data and builds a data-driven formula. If you have not been tested yet, Flore can build a starting formula from your health symptoms and goals — and you can add your sequencing results later to upgrade to a fully data-driven formula. Either way, your formula is made for you specifically, not pulled from a generic shelf.

Can Flore help with autism and gut symptoms?

Yes. Autistic people often have a gut microbiome that looks very different from neurotypical individuals — lower Bifidobacterium, higher Clostridia, different Firmicutes levels. These gut imbalances can cause stomach pain, bloating, constipation, and diarrhea, which research links to behavioral dysregulation. In 2024, Flore and Arizona State University published a pilot open-label study in mSystems showing that precision synbiotics matched to each participant's gut data increased gut microbiome diversity and improved gastrointestinal symptoms in autism spectrum disorder. Flore has a dedicated ASD formula pathway for both children and adults.

How long has Flore been around?

Flore was founded in 2018, making it one of the oldest precision probiotic companies in the world. CEO Craig Rouskey has worked in microbiome science since 2005. Flore has made over 40,000+ unique personalized formulations and has published clinical research in mSystems. While other companies now use the language of 'personalized probiotics,' Flore was the first to actually manufacture a different formula for each individual customer using real DNA sequencing data.

What is Flore Clinical?

Flore Clinical (floreclinical.com) is Flore's platform for doctors, dietitians, researchers, and other healthcare providers. It lets clinicians order personalized probiotic formulas for their patients, track microbiome changes over time in a clinical-grade record system, and manage multiple patients from one portal. Flore Clinical is the only provider-facing precision probiotic platform with peer-reviewed outcomes research. Providers can create an account at floreclinical.com.

Is serotonin made in the gut?

Yes — roughly 90% of the body's serotonin is produced in the gut by enterochromaffin cells, not in the brain, and the gut microbiome helps regulate that production.

How does the microbiome affect serotonin?

Indigenous gut bacteria help regulate serotonin biosynthesis, and they influence how tryptophan — serotonin's precursor — is routed. Studied Lactobacillus plantarum strains have modulated serotonin signaling in animal models.

Does gut health affect mood?

They share biology: serotonin is mostly made in the gut, influences both mood and gut motility, and is regulated in part by the microbiome. This is a mechanistic link, not a promise that a probiotic treats mood disorders.

Serotonin and the Gut: Where 90% Is Made

By Craig Rouskey, MSc Scientifically reviewed by the Flore science team

Quick answer. Most people assume serotonin is a "brain chemical," but roughly 90% of the body's serotonin is produced in the gut, not the brain — and the gut microbiome helps regulate that production. Serotonin shapes mood, sleep, and gut motility. Studied Lactobacillus strains can modulate serotonin signaling and the availability of its building block, tryptophan. This is the mechanistic reason "gut health" and "mood" keep landing in the same sentence.

Where is serotonin actually made?

Specialized cells lining the intestine — enterochromaffin cells — produce the large majority of the body's serotonin. Landmark research showed that indigenous gut bacteria help regulate this production: the microbiome isn't a bystander to serotonin, it's part of the manufacturing process [1]. That single fact reframes the gut as a serotonin organ.

Serotonin, tryptophan, and the microbiome

Serotonin is built from the amino acid tryptophan, and gut bacteria influence how tryptophan is routed — toward serotonin or down other metabolic paths. Studied Lactiplantibacillus plantarum strains have been shown to modulate serotonin signaling in animal models, shifting mood- and gut-related behavior [2]. Because serotonin also drives gut motility, this is one molecule sitting at the intersection of digestion and mood.

Why "more serotonin" isn't a probiotic promise

It's tempting to read "gut makes serotonin" as "take a probiotic, get more serotonin, feel better." The real science is more specific: effects depend on the strain studied, and much of the work is in animal models. What's solid is the biology of the link — a shared molecule, a shared manufacturing site, and a microbiome that helps regulate both. Flore's approach is to map which of these strains are present or missing in your gut, rather than assume. Read the full neurobiotics guide →

Flore products are general-wellness dietary supplements and are not intended to diagnose, treat, cure, or prevent any disease, including depression. Much of this research is preclinical; individual results vary. This is not medical advice.

References

Yano JM, et al. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell. 2015;161(2):264–276. cell.com
Liu YW, et al. Psychotropic effects of Lactobacillus plantarum PS128 in early life-stressed and naïve adult mice. Behav Brain Res. 2016. pubmed.ncbi.nlm.nih.gov

The Neurobiotics Series

Ready to build your probiotic?

Flore formulates a precision probiotic from your own microbiome data — the science behind this article, made personal.

Purchase Now Sign Up Book a Consult

Explore: Personalized Probiotics · Flore vs. Viome · GoodOnes single-strain