Bacteriophages Poised to Revolutionize Gut Health as Manufacturing Hurdles Drop

Probiotic supplements have become the fastest-growing supplement products on the market, and consumers are paying more attention to their guts than ever. Yet the tools they reach for may not do what they expect. A 2026 study in Clinical Gastroenterology and Hepatology by Nutrition Insight shows that use of probiotic supplements jumped 287% among US adults and 786% among people under 20 between 2009 and 2023, even as consumption of microbiome-supporting foods barely changed. The American Cancer Society notes that colorectal cancer is expected to claim about 55,230 lives in the United States in 2026, with incidence rising in people aged 20 to 49.

The probiotic story has had huge interest for about 25 years. Since the first probiotics reached consumer shelves around the year 2000, the message has been simple. Take good bacteria to crowd out the bad. But the science has become more complicated. Probiotics do attach to the gut as transient visitors, yet research from Oxford Academic suggests that incoming probiotics face strong colonization resistance. The bad bacteria can stay colonized, and the rebalancing usually does not happen on its own.

Modern food processing has also removed much of the living biology from the American diet. Pasteurization, common in everyday foods and beverages, kills the microbes that would otherwise reach the gut. A pasteurized product is safer from a food safety standpoint, yet it tends to arrive with all living life gone. People who eat mostly pasteurized foods may be missing the microbial input their systems evolved to expect.

This leaves consumers in a difficult position. The supplement industry built its recommendations around bacteria, and shoppers responded in record numbers. But a gap has opened between what people are taking and what their microbiomes actually need. In some cases, the result is rising sales and little meaningful change in long-term gut health.

William Marsh of PhageFarm could be building an answer to that gap. An entrepreneur in San Diego, Marsh is preparing to launch a microbiome company built around bacteriophages, the viruses that target and destroy specific bacteria. Phages have been taught in university biology courses for decades; what is new is the manufacturing. While thousands of probiotic makers exist, very few appear to produce bacteriophages at scale. "My partner and I actually know how to make them on a large scale, whereas really there are not many that know how to do that," Marsh says.

Bacteriophages work differently from probiotics. Instead of adding bacteria to the gut, they remove the harmful ones. A phage cocktail can find a target pathogen such as E. coli or Salmonella and safely eliminate it while leaving the good bacteria in place. Marsh compares the approach to precision work rather than a blunt instrument. His current lineup includes E. coli, Salmonella, and staph cocktails, each neutralizing a specific pathogen.

The manufacturing story aims to be central to the mission. Marsh describes his work as precision fermentation combined with regenerative agriculture, producing what he calls ingredients of the future. "We're not drugs. We're over-the-counter safe," he says. Each dose carries 1,000,000 plaque-forming units, and according to him, clinical studies were completed earlier this year. He notes that because ingredients are fermented rather than harvested from variable crops, quality controls are exact.

Marsh sees the products as tools for real life, not just a supplement line. He is of European descent and lives near the Mexican border. He avoided drinking local water because his gut could not handle unfamiliar microbes. According to Marsh, the phages in his system changed that. "I couldn't drink the water, but I can now because I take phage," he explains. In San Diego, where sewage from Tijuana may have carried E. coli and Salmonella into local swimming spots, he believes the same tools could protect families.

The longer-term promise is about balance. Marsh describes the gut in two states: "Dysbiosis, when bad bacteria outcompete the good, and symbiosis, when both are balanced." His first product carries the tagline symbiosis in a bottle. If phages remove the harmful bacteria that have colonized the gut for years, probiotics could work better. He points to E. coli that sits in the colon for years as one factor linked to colon cancer risk and suggests periodic phage use could help remove it.

After 25 years of probiotics, the next chapter in gut health may belong to a different kind of biology. Bacteriophages do not replace the idea of good bacteria; they change what it takes to achieve it. As consumers keep spending on supplements and public health data keeps pointing to a disrupted microbiome, the industry may finally move beyond the same story. If Marsh's breakthrough delivers, gut health could become less about adding and more about removing what is in the way.