Smart underwear detects lactose intolerance by tracking your farts – Image for illustrative purposes only (Image credits: Unsplash)
Flatulence affects daily life for millions, often signaling underlying digestive issues like lactose intolerance that go undiagnosed. Researchers at the University of Maryland have developed a coin-sized sensor that clips onto underwear to objectively measure gas emissions, offering a non-invasive way to track gut activity. Presented on May 4, 2026, at the Digestive Disease Week conference in Chicago, the device demonstrated its ability to detect lactose sensitivity through changes in hydrogen gas production.[1][2]
How the Device Captures Flatulence Data
The Smart Underwear consists of a small electrochemical sensor, roughly the size of a nickel and a couple of coins thick, positioned near the perineum when snapped onto standard underwear. It continuously detects hydrogen gas, a byproduct of gut bacteria fermenting undigested carbohydrates, distinguishing true flatulence events from other emissions. Battery life extends up to a week, allowing for real-world monitoring without frequent recharges or discomfort – 95 percent of 19 test wearers reported no issues after six or more days.[1][3]
Brantley Hall, an assistant professor at the University of Maryland who led the development, compared the technology to a continuous glucose monitor but for intestinal gas. The sensor logs frequency and hydrogen spikes, providing data that self-reports often miss, especially during sleep or distraction. Initial prototypes proved 94.7 percent sensitive in detecting fiber-induced gas increases.[2]
Baseline Findings Challenge Common Assumptions
Healthy adults pass gas an average of 32 times per day, ranging from 4 to 59 events, according to a study published in Biosensors and Bioelectronics: X. This figure nearly doubles the 14 episodes typically cited in medical literature, which relied on self-reporting or small, invasive lab tests. Participants in the research underestimated their output significantly, highlighting the unreliability of subjective tracking.[3][2]
Hall noted that people prove poor judges of their own patterns: “It’s literally like a coin flip. People aren’t reliable narrators about their flatulence patterns.”[1] Variations stem from diet, microbiome differences, and visceral sensitivity, where identical gas volumes feel different to individuals.
Lactose Sensitivity Test Yields Clear Results
In a controlled trial with 37 participants, researchers established a low-fiber baseline over two days to quiet microbiome activity. Subjects then consumed either 20 grams of lactose or sucrose blindly on alternating days. The device identified 24 lactose-sensitive individuals who produced over 1.5 times more gas after lactose, with 22 cases aligning hydrogen spikes precisely to the offending sugar. Even so, these participants correctly identified their gassier day only half the time via symptoms alone.[1]
About one-third of lactose-intolerant people remain asymptomatic yet still generate excess gas from bacterial fermentation of undigested dairy sugars. The sensor’s extended monitoring – far beyond clinic breath tests – captures real-life patterns, including post-meal delays of three to four hours for gas peaks. A separate fiber challenge confirmed the tool’s precision, spotting inulin effects where sugar gumdrops triggered none, despite some reporting discomfort from expectation.[3] This longer section underscores the device’s validation across diets, paving the way for broader use.
First author Santiago Botasini and Hall have patented the tech and launched Ventoscity LLC to commercialize it, with University of Maryland licensing support.
Key Study Contrasts:
Self-reported average: 10-20 farts/day
Device-measured: 32 farts/day
Lactose challenge accuracy: 22/24 cases matched
Fiber detection sensitivity: 94.7%
Broader Implications for Digestive Disorders
Beyond lactose intolerance, the sensor targets irritable bowel syndrome, small intestinal bacterial overgrowth, and other food sensitivities by quantifying fermentation objectively. Traditional diagnostics like breath tests limit data to hours; this wearable spans days in natural settings. It could assess drugs or probiotics aimed at curbing gas, addressing gastroenterologists’ long-standing frustration with unverifiable complaints.[2]
Hall emphasized the gap: “We don’t actually know what normal flatus production looks like. Without that baseline, it’s hard to know when someone’s gas production is truly excessive.”[3]
Mapping the Human Flatus Atlas
The ongoing Human Flatus Atlas recruits hundreds via flatus.info, categorizing participants as Zen Digesters (high-fiber, low-gas), Hydrogen Hyperproducers (frequent emitters), or normals. Stool samples link patterns to microbiomes, informing interventions. Over 10,000 expressed interest, signaling public curiosity about this once-taboo metric.[2]
As baselines emerge, the technology promises to demystify gut health, turning an embarrassing symptom into actionable insight. Researchers anticipate refined versions aiding everyday diagnostics soon.