Scientists Create “Smart Underwear” To Measure How Often We Really Fart
But would you really call it "smart?"
By Georgia Jiang, University of Maryland
| Smart Underwear model. Credit: Brantley Hall, University of Maryland. |
Researchers at the University of
Maryland have unveiled what they describe as the first wearable device
built specifically to measure human flatulence.
Known as Smart Underwear, the discreet sensor system tracks hydrogen gas released during flatus, giving scientists an objective way to study a bodily function that has long relied on guesswork and self-reporting.
Beyond counting how often people pass gas, the technology offers a new tool for
observing gut microbial activity in daily life.
Measuring what medicine could not
Excess intestinal gas is a common complaint in medical
offices, yet doctors have historically lacked reliable tools to measure it. As
gastroenterologist Michael Levitt, often referred to as the “King of Farts,”
wrote in 2000: “It is virtually impossible for the physician to objectively
document the existence of excessive gas using currently available tests.”
To overcome this limitation, a team led by Brantley Hall, an
assistant professor in the Department of Cell Biology and Molecular Genetics at
UMD, developed a compact wearable sensor that attaches to regular underwear.
The device uses electrochemical sensors to continuously monitor intestinal gas
production throughout the day and night.
In research published in Biosensors and
Bioelectronics: X, UMD assistant research scientist Santiago Botasini and
colleagues reported that healthy adults passed gas an average of 32 times per
day. That figure is about twice the commonly cited estimate of 14 (±6) daily
episodes found in medical literature. The range between individuals was
striking. Some participants recorded as few as four events per day, while
others reached 59.
Earlier estimates were likely lower because they depended on invasive laboratory setups with small sample sizes or on participants tracking their own gas episodes. Self-reporting can miss events, especially during sleep, and memory is not always reliable. In addition, people experience gas differently. Two individuals may produce similar amounts, yet one feels significant discomfort while the other notices very little.
“Objective measurement gives us an opportunity to increase
scientific rigor in an area that’s been difficult to study,” said Hall, the
study’s senior author.
| Members of the team led by Brantley Hall, an assistant professor in the Department of Cell Biology and Molecular Genetics, demonstrate a prototype of the Smart Underwear wearable device at Maryland Day. Credit: University of Maryland |
Hydrogen as a microbiome signal
Human flatus is primarily composed of hydrogen, carbon
dioxide, and nitrogen. Some people also produce methane. Hydrogen is especially
important because it is generated exclusively by microbes in the gut as they
break down undigested carbohydrates. By continuously measuring hydrogen levels,
researchers can observe when and how actively the microbiome is fermenting
food.
“Think of it like a continuous glucose monitor, but for
intestinal gas,” Hall said.
In testing, the device detected spikes in hydrogen after
participants consumed inulin, a prebiotic fiber known to stimulate microbial
fermentation. The system identified these increases with 94.7% sensitivity,
demonstrating that it can capture real-time changes in microbiome activity
linked to diet.
This type of monitoring could eventually help scientists
better understand how specific foods, probiotics, or prebiotics influence gut
function outside the lab.
Hall’s team is recruiting participants across several
categories that emerged from their early studies, including Zen Digesters
(those with high-fiber diets yet produce minimal flatus) and Hydrogen
Hyperproducers (simply put, those who fart a lot). Credit: Brantley Hall,
University of Maryland
Launching the Human Flatus Atlas to map the normal range
of flatulence
Medicine has well-established reference ranges for measures
such as blood sugar and cholesterol. Flatulence, despite being a universal
human function, has no widely accepted standard.
“We don’t actually know what normal flatus production looks
like,” Hall said. “Without that baseline, it’s hard to know when someone’s gas
production is truly excessive.”
To establish that reference point, the Hall Lab is launching
the Human Flatus Atlas. The project
will use Smart Underwear to track gas production in hundreds of adults across
the United States. Participants can enroll remotely and receive devices by
mail, making it possible to gather data from a broad and diverse population.
Researchers will analyze patterns over 24-hour cycles and compare results with
participants’ diets and microbiome profiles. The goal is to define what typical
flatus production looks like for U.S. adults over 18.
Early findings have already revealed distinct groups:
- Zen
Digesters: Individuals who eat high fiber diets (25–38 grams of fiber
daily) but report very little gas. Researchers believe this group may
provide insight into how the gut microbiome adapts to fiber-rich eating
patterns.
- Hydrogen
Hyperproducers: In simple terms, people who pass gas frequently. Studying
this group may help scientists understand the biological and microbial
factors that contribute to high levels of gas production.
- Normal
People: Those whose gas production falls between the two extremes,
representing the broad middle range of typical digestive patterns.
To better understand the microbial mechanisms at work,
researchers will collect stool samples from Zen Digesters and Hydrogen
Hyperproducers for detailed microbiome analysis.
“We’ve learned a tremendous amount about which microbes live
in the gut, but less about what they’re actually doing at any given moment,”
Hall said. “The Human Flatus Atlas will establish objective baselines for gut
microbial fermentation, which is essential groundwork for evaluating how
dietary, probiotic or prebiotic interventions change microbiome activity.”
By transforming an everyday bodily function into measurable
data, the project could reshape how scientists study digestion, diet, and the
trillions of microbes that call the human gut home.
Reference: “Smart underwear: A novel wearable for long-term
monitoring of gut microbial gas production via flatus” by Santiago Botasini,
David Zhan, Norman Fischer, Charlotte T. Ravel, Ashley Tien, Maggie R. Grant,
Glory Minabou Ndjite, Ty Sopko, Holly Childs, Maryann Greenfield, Christina X.
Qian, Kara E. Gardiner, Nayantara M. Anders, Tasnim F. Ullah, Leah T. Redmond,
Delaina A. Callaway, Eliya M. Behailu, Grace M. Sarkar, Nakati C. Sany,
Margaret Slavin and Brantley Hall, 10 October 2025, Biosensors and
Bioelectronics: X.
DOI:
10.1016/j.biosx.2025.100699
This research was supported by the University of Maryland,
the Maryland Innovation Initiative Phase I and the UM Ventures Medical Device
Development Fund.
To enroll in the Human Flatus Atlas, please visit flatus.info for more information.
Enrollment is open to adults ages 18 years or older in the U.S. Participants
will receive a Smart Underwear device to wear day and night for the study
period. Enrollment is limited.
Patent applications related to this technology have been
filed, with Brantley Hall and Santiago Botasini as inventors. Both are
co-founders of Ventoscity LLC, which has licensed the technology.