• Posted November 12, 2025

The Hype and Limits of At-Home Gut Microbiome Tests

The market for at-home gut microbiome tests is booming, with companies promising insights into health, chronic illness and even longevity through intestinal bacteria.

But many gastroenterologists are urging consumers to be cautious, according to The Associated Press, as the science backing these direct-to-consumer tests is extremely limited.

The human gut is home to a complex ecosystem of microbes that aid in digestion, vitamin absorption and fighting inflammation. While research suggests a healthy microbiome may influence conditions like liver disease, diabetes and mental health, physician experts say their understanding of this is in the very early stages and much is unknown.

“Most of the variability between people, we don’t understand,” Dr. Eamonn Quigley, chief of gastroenterology and hepatology at Houston Methodist Hospital, told The AP. 

These tests typically involve mailing a stool sample to a lab, which then provides a report comparing the person's microbial mix to a presumed "ideal," and highlights gut imbalances in a long list of bacteria. 

The tests can cost up to $500 or even more.

One key issue is that these tests are not federally regulated or intended for clinical use. As such, the scientific basis and reliability of the tests vary from company to company.

When patients show doctors these reports, the results often lead to frustration. 

“The technology is jumping ahead of the clinical application,” Quigley explained. “Just because you can measure something doesn’t mean to say it’s worthwhile.”

Doctors have limited proven tools — aside from diet and antibiotics — to change a patient’s microbiome. Dr. Sean Spencer, a physician scientist at Stanford University, told The Associated Press that the lack of effective interventions is a major hurdle. 

He said the frustration for doctors is with the lack [of] tools to change the microbiome.

Outside of occasionally detecting inflammation or pancreatic function, doctors say that for most people, these expensive tests don't provide information that doctors and patients can work with.

Another concern is the potential conflict of interest among test providers. Nearly half of the companies offering these tests also sell supplements or probiotics that they recommend based on the test results. 

Since these supplements are not regulated as drugs by the U.S. Food and Drug Administration (FDA), there is little certainty about their effectiveness or whether they even contain what they claim.

The U.S. Department of Health and Human Services recommends these steps to improve your gut health:

• Have smaller meals.

• Eat slower. 

• Limit what you eat after dark. Don’t eat late. 

• Manage stress. 

• Create a routine for when you eat. 

• Consider taking probiotics (healthy bacteria). 

More information

The American Medical Association also has suggestions on how to improve your gut health.

SOURCE: The Associated Press, Nov. 3, 2025