First-in-Class Dietary Supplement a Potentially Big Win for Babies

By Deborah Borfitz 

September 9, 2025 | Modern medical practices like antibiotics and C-sections, coupled with an industrialized food system that prioritizes high yields and profitability over nutritional quality, have left most babies born today lacking the gut microbes they need before kindergarten to train their immune system for life. The deficiency in these types of Bifidobacterium affects all but a fraction of infants in the United States, putting them at risk for developing atopic disease conditions that include food allergies, eczema, and asthma, according to Stephanie Culler, Ph.D., co-founder and CEO of Persephone, a biotech company specializing in developing microbiome-based medicines. 

Worried parents can find a fix with a first-in-class dietary supplement, Persephone’s Daily Synergistic Synbiotic, available as of today from the company’s e-commerce site. It’s sold as a powder and designed for infants and toddlers up to 36 months of age, but individuals of any age can use the product to restore missing microbes from their gut.  

“The majority of people are in an unhealthy microbiome state,” explains Culler, calling attention to concerning population health statistics and survey results. An estimated 40% of adults in the U.S. are obese and roughly 60% to 70% of Americans complain about some kind of gut issue.  

But the microbiome of infants and toddlers is far less complex and diverse than that of adults, making the problem in their gut more obvious and addressable, she says. The evidence comes from two study “firsts”—Persephone’s randomized, double-blind, placebo-controlled ARTEMIS study (now in data evaluation mode) and the seven-year My Baby Biome study (now in its third year). ARTEMIS is a clinical trial involving more than 100 infants and toddlers and is the largest infant synbiotic study in the U.S. to date, reports Culler. The My Baby Biome study, with more than 400 enrollees, is the largest and most diverse clinical study to map the microbiome of infants in the country.  

The over-the-counter product was “born out of research” and precisely tailored to what the data showed. 

Evidence Build 

The landmark My Baby Biome study maps the infant gut microbiome using metagenomics and metabolomics. Participants are now in their third year of life and more than 90% of those babies have a deficiency in one or more keystone strains of Bifidobacterium (Communications Biology, DOI: 10.1038/s42003-025-08274-7). 

Concerningly, the children with Bifidobacterium missing or at very low levels are at much higher risk, “approximately threefold risk higher,” of developing atopy, Culler says. “Other studies also support that these missing bacteria are associated with obesity and even diabetes.” 

Data from the My Baby Biome study revealed that babies need three types of Bifidobacterium, of which B. infantis is the “superhero” because it consumes all the prebiotics found in breast milk (human milk oligosaccharides, or HMOs), Culler says. In babies ages one to three months, this once-prevalent keystone species in the gut was “almost gone.” 

For the 8% of babies who had the microbe, two strains of the B. infantis species were found. To ensure every child would get the right strain, she says, both were incorporated into the new synbiotic. 

Persephone’s Daily Synergistic Synbiotic also contains two other strains, B. breve and B. longum, which consume HMOs as well as eat plant-based sugars that are important for children as they transition to solid foods and for adults to utilize prebiotics in their diet. In addition to those three species of Bifidobacterium, the supplement contains 400 IU of vitamin D, which is 100% of the recommended daily value for babies—and a lot less messy to deliver as a powdered formula than using a dropper, says Culler, speaking as the mother of a now-4-year-old daughter.  

HMOs are also in the mix and uniquely include representatives of each structural class of sugars found in breast milk, Culler continues. “These special prebiotics feed the probiotic [Bifidobacterium] strains; they synergize and basically colonize and grow in the infant gut.” 

Scientists first coined the term “synbiotic” in 1995. It essentially means the combination of a probiotic and a prebiotic, says Culler. Persephone’s dry powder formulation is flavorless and easy to add to formula, expressed breast milk, or soft foods. 

The product meets all the regulatory requirements of the Food and Drug Administration (FDA) for a dietary supplement, and its ingredients are designated as “generally recognized as safe” (GRAS), she says. Since publication of the My Baby Biome study, “we’re getting a lot of attention and a lot of partnership with physicians” that favors the company’s ambition to make the Daily Synergistic Synbiotic part of standard clinical practice. 

Before the end of the year, the product will be available for purchase on Amazon and later next year possibly also in retail stores, says Culler. The supplement is being sold for a subscription cost of $64.95 monthly. 

Being a biotech company, as well as a research and development organization, Persephone is looking at leveraging its growing knowledge base on the microbiome to develop therapeutics for treating various atopic diseases, she adds. It also has a lot of biomarker data and might eventually want to partner with a diagnostics organization. 

Poop-to-Product Pivot 

Persephone was founded eight years ago to develop a technology platform and products to prevent and treat disease through the gut microbiome, says Culler. The initial focus was on oncology, to help cancer patients respond to their treatment, but along the way she learned about critical imbalances in the infant gut microbiome that was viscerally upsetting to her as a mom and a microbiome expert. 

It began with a conversation Culler had in early 2022 with Richard Insel, M.D., then a pediatric clinician with Johnson & Johnson, and now Persephone’s chief medical advisor and a research professor at the University of Rochester School of Medicine and Dentistry. He suggested that the work Persephone was doing to improve the immune system of cancer patients could be “hugely impactful” for infants. Culler’s own daughter was six months old at the time.  

She had by then finished her Ph.D. at the California Institute of Technology, becoming one of the first graduates in the synthetic biology field. Her focus was on genetic engineering with an eye toward developing new gene or cell-based therapies for preventing cancer, a disease that unexpectedly claimed the lives of both her grandmothers six months apart. 

Culler also wanted to be an entrepreneur, the path taken by everyone in her family. To gain that experience, she traveled to San Diego to work for an industrial biotech, genetically engineering microbes through fermentation to produce useful compounds, where she met her eventual Persephone cofounder and Chief Technology Officer Steve Van Dien, Ph.D., and several of its employees. This is when she knew she wanted to take that kind of rigorous science to start a company devoted to human health, and she quickly homed in on the microbiome, Culler says. 

She was fascinated by discoveries that had emerged from the Human Microbiome Project of the National Institutes of Health, whose 2007 launch set off an explosion of research interest in finding connections between the human microbiome and human health and disease. With heavy reliance on advanced sequencing technologies, the project effectively linked virtually every known disease to the gut microbiome—"from how cancer patients respond to treatment to how babies' immune systems develop for life,” Culler says. 

For the first five years of the company, the “poop to product” platform was focused only on cancer, notably improving the response rate of patients to immunotherapy drugs. One of Persephone’s partners on this mission was Johnson & Johnson, on a project looking at colorectal cancer, which is where Dr. Insel comes in. 

Diaper Collection 

Following her conversation with Insel about the global infant microbiome problem, Culler was upset but also a bit skeptical that “pretty much every kid” was affected. So, she texted her friend with a young baby who knew everyone else in town who had babies and messaged the moms, asking if her husband could come pick up their soiled diapers so she could sequence the poop. 

In a matter of days, Culler had readouts on the 20 babies, and she was shocked to the point of tears, she recalls. “Almost all of the babies had these [Bifidobacterium] microbes missing.” These newborns had “many of the pathogenic or potentially pathogenic infectious organisms we see in advanced stage cancer patients” as well as multiple sclerosis and a suite of other diseases. 

After reviewing all the published literature on the issue, she was convinced not only that Persephone could provide the fix but that it was going to be an easy and important remedy relative to the company’s longer-term ambitions in the cancer space. The urgency to restore vital gut microbes is real, says Culler, because the clock is literally ticking for them. Development of the gut microbiome's relationship with the immune system ends by age 4 or 5, after which it stabilizes and reaches an adult-like composition. 

Data supporting the need for this type of supplementation comes from global studies that have mapped out the gut microbiome of children up to age 8, Culler says. Kids start off with maybe a dozen or so types of bacteria in their gut, which increases to several hundred strains by the time they reach adulthood.   

Longtime Focus on the Gut  

Studies from around the world suggest “a very significant need for supplementation,” she says. The problem is associated with not only antibiotic use but also a poor diet incorporating a lot of ultra-processed food. “All these things have a dramatic impact on how the microbiome develops for life.” 

In addition to the many organisms populating the adult gut, the added complexity is the diversity of foods people eat and the highly personalized ways that food gets metabolized. “It’s the biggest outstanding challenge for the microbiome space, not just us as a company,” says Culler. 

Restoring the gut microbiome health of adults is the future focus of Persephone, Culler says, since most people likely need some type of supplementation to potentially improve their physical and mental well-being. People with cancer and chronic diseases can often be distinguished from healthy people based on their microbial compositions. “There are tens of thousands of publications to back that up.” Over the last 20 years, more than 100,000 scientific papers on the gut microbiome alone have been published. 

But the importance of what’s happening in the gut has been well appreciated for at least 2,000 years, Culler notes. “Hippocrates, the father of modern Western medicine, says all disease begins in the gut ... [and] around that same time in ancient China they were using yellow cocktails, which were [oral] fecal transplants, to give people relief from food poisoning and other types of infections.”  

The FDA has approved two fecal microbiota products (Rebyota and Vowst) for preventing recurrent Clostridioides difficile infection (CDI) in adults, she continues, but the agency has been clear about the regulatory challenges. “With fecal transplants, the human is the producer of the therapy, and that is very hard to control.”   

Persephone prefers to analyze poop samples and drill down to the exact microbes in the microbiome that can help patients regardless of the disease. All the products under its “Poop for a Cure” umbrella are designed to be pure, effective, and scalable with a defined mechanism of action, says Culler.    

Food as Medicine 

Persephone is learning a lot about properly balancing metabolism in the gut from its work in oncology as well as a “food as medicine” AMBROSIA study in partnership with Kroger looking at the extraction of nutrients from the diet, she adds. The two-cohort study has enrolled over 400 individuals in the U.S. who are at high risk for developing colorectal cancer based on having first-degree relatives with the disease, certain readouts from colonoscopies, or by virtue of lifestyle factors such as obesity and smoking. Half of the participants will be receiving medical nutrition therapy provided by Kroger dieticians. 

The objective of AMBROSIA is to see if the intervention improves the quality of their diet, based on self-reporting and gut microbiome changes that support potential changes in health as detected in analyzed stool samples, says Culler. Ultimately, the goal is to give people individualized food prescriptions. 

Results of the study are expected to be published in the first half of 2026, Culler says. Persephone is actively looking to expand its work on the food-as-medicine front. 

Artificial intelligence will be used to analyze the vast amount of information that will be gathered on people’s diets, including whether and to what extent they eat organic produce, she says. The company also has built machine learning algorithms in-house to handle microbiome-specific data being gathered in its Poop for a Cure clinical studies.