A separate mechanistic study found that the postbiotic exerted its benefits via three synergistic mechanisms of action: improved gut barrier function, immune modulation, and supporting gut keystone bacteria.
Findings from both studies are published in the journal Beneficial Microbes.
Postbiotics were defined by the International Scientific Association of Probiotics and Prebiotics (ISAPP) as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host” (Salminen, 2021).
Keystone
The study used Verb’s Keystone-branded postbiotic, which was launched commercially in 2025. The ingredient is produced by fermenting oat flour in the presence of Lactiplantibacillus plantarum 276 and Lacticaseibacillus rhamnosus GG. Subsequently pasteurized and freeze-dried, the oat-based preparation reportedly contains non-viable microbial biomass and fermentation-derived signals.
The ingredient is already included in more than 12 consumer brands, with a strong pipeline of new product launches ahead, said Todd Beckman, CEO of Verb Biotics.
“Together, the mechanism of action paper and clinical paper tell a much more complete story than either paper could on its own,” said Beckman. “The MOA paper shows how Keystone works: supporting gut barrier function, driving a bifidogenic effect, and supporting wound repair at the cellular level. The clinical paper then translates that mechanism into measurable shifts in the human gut microbiome and host biomarkers. It is rare to have the mechanism and clinical outcome published so closely together.”
Beckman added that the core benefit delivered by Keystone is targeted microbiome support, and the ingredient is not designed to introduce new organisms into the gut. Rather, it is designed to help strengthen the keystone species already there.
“In our 4-week trial, 33 beneficial species, including Akkermansia and Bifidobacterium, were significantly enriched, while 38 taxa linked to GI distress were reduced,” he said. “What really jumps out is the speed of the response. To see that level of targeted microbiome shift in just four weeks is pretty remarkable, especially from a 300 mg postbiotic dose. That is a fundamentally different approach than many probiotics on the market today, and one supplement brands can point to as a precise, differentiated way to support gut health.”
Study details
For the clinical trial, researchers from Verb Biotics, the Center for Applied Health Sciences, Keller Consulting Group, and BioRankings Statistical Consulting recruited 76 healthy adults and randomly assigned them to receive either the Keystone postbiotic or placebo for four weeks.
Results showed that, while the postbiotics did not affect alpha or beta diversity, further analysis showed an enrichment of Akkermansia spp., Bacteroides intestinalis, Bifidobacterium pseudocatenulatum, and Anaerostipes caccae in the Keystone group. In addition, a lower abundance of several Haemophilus, Megasphaera, and Prevotella taxa was reported, compared to placebo.
Reductions in the pro-inflammatory cytokine IL-8 and morning cortisol levels were also reported.
Data from the mechanistic studies in Caco-2 cells and in the C. elegans model showed that the postbiotic was also associated with improved integrity of the intestinal barrier.
Verb’s Beckman said that a notable takeaway from the clinical trial was emotional wellness, adding that 68% of participants reported improved emotional well-being, alongside a healthier relationship between morning cortisol and the gut ecosystem in the Keystone group.
“That lines up with what we know about the gut-brain axis and how the gut is in constant conversation with the nervous and endocrine systems,” he said. “Having a postbiotic clinically tied to emotional wellness, not just digestion, is a meaningful step for the category.
“This also points to a broader shift,” added Beckman. “For years, digestive health has been about diversity: more strains, more CFUs. We believe the next era is about resilience, strengthening the ecosystem that is already there so it can better adapt to stress, diet, and age-related decline. As more people think about healthy aging, a resilient gut microbiome will be foundational to that conversation, not an afterthought.”
Sources:
Beneficial Microbes, 2026, doi: 10.1163/18762891-bja00129. “The effects of a postbiotic supplement on biomarkers of microbiome, gastrointestinal, cardiometabolic, and immunometabolic health”. Authors: C.J. Delebecque, et al.
Beneficial Microbes, 2026, doi: 10.1163/18762891-bja00125. “Mechanistic characterisation of a novel oat-based postbiotic: microbiome modulation, barrier protection, and wound healing”. Authors: A. Aditya, et al.
