NIST Detects THC in Breath After Ingesting Cannabis‑Infused Edibles

USA: NIST Detects THC in Breath After Ingesting Cannabis‑Infused Edibles

Researchers at the National Institute of Standards and Technology (NIST) announced the first successful measurement of tetrahydrocannabinol (THC) in exhaled breath following consumption of cannabis‑infused edibles, a study published in July 2025. The work involved 29 adult participants who provided breath samples before and for three hours after ingesting gummies containing 5 to 100 mg of THC.

Study Design

The experiment was conducted in collaboration with the University of Colorado Anschutz Medical Campus. Participants were instructed to abstain from cannabis for eight hours prior to the test, then supplied a breath sample, consumed a single edible, and provided additional breath samples roughly every hour for three hours. Researchers quantified THC and other cannabinoids using NIST‑validated analytical methods.

Key Findings

Baseline breath samples already contained detectable THC in most participants, reflecting the slow clearance of cannabinoids from the body. Nineteen participants exhibited statistically significant increases in breath THC within the three‑hour observation window, typically showing a peak followed by a decline. Four participants showed no measurable change, and six demonstrated a decrease from the initial sample, suggesting variability in absorption and exhalation timing.

Implications for Testing

The results demonstrate that THC from ingested products can reach the lungs and be exhaled, contradicting the notion that breath THC originates solely from smoked residue. Because THC is less volatile and present at lower concentrations than alcohol, detecting it reliably requires highly sensitive instrumentation and standardized protocols.

Expert Commentary

“This is an important step forward, that we can detect THC increases in breath after the ingestion of cannabis,” said Jennifer Berry, NIST research chemist and lead author. Kavita Jeerage, a NIST chemical engineer on the project, noted that the data provide a foundation for future work on impairment assessment. Tara Lovestead emphasized that multiple breath measurements over time could inform a breathalyzer approach, but warned that “devices will still need standards to ensure that they are accurate and used correctly,” adding that such standards are not yet established.

Next Steps

NIST is not developing a commercial breathalyzer but will host a workshop in September with device developers to discuss measurement standards and potential pathways for reliable roadside testing. The research team plans further studies to map the timing of THC appearance and clearance in breath after edible consumption.

Publication Details

The study, titled “The detection of cannabinoids in breath after ingestion of cannabis‑infused edibles,” appeared online in the Journal of Analytical Toxicology on July 10, 2025 (DOI: 10.1093/jat/bkaf063).

This report is based on information from NIST, licensed under Public Domain (U.S. Government Work). Source: Official U.S. Government release.