Can THC in Breath Identify Recent Edible Use? Why Baseline Measurements Matter
THC can increase in breath after an edible, but a single positive breath result does not reliably establish recent ingestion or impairment. A human proof-of-concept study found substantial variation, including positive samples collected before the observed dose.
What the study actually collected
Berry and colleagues studied 29 participants who brought their own cannabis gummies. Breath was sampled before ingestion and approximately 47, 92, and 180 minutes afterward. Two collection approaches captured either exhaled aerosols or condensate, with cannabinoids measured by liquid chromatography–tandem mass spectrometry.
Reported quantities were normalized to collection devices. They should not be relabeled as blood concentrations or as measurements equivalent to an alcohol breathalyzer.
Not every participant showed a post-dose rise
Nineteen participants had their highest THC measurement after dosing, six had their highest measurement before dosing, and four showed no significant change under the authors’ criterion. THC was detected before dosing in 27 participants. Requested abstinence was not independently established in a closed research unit.
The fold-change criterion addressed uncertainty pragmatically; it was not a validated diagnostic cutoff for impairment. Device sampling, aerosol production, breath volume, recovery, and biological variability remain relevant.
What a single result leaves unresolved
The observation period ended at three hours, and some peaks may have been missed. Product labels were not independently verified, doses varied, and the two devices were not directly validated against each other as interchangeable methods.
The experiment establishes the feasibility of recovering cannabinoids after edible ingestion. It did not correlate breath measurements with dose or impairment. Before using a result to date consumption, ask whether repeat baseline measurements and an independently validated timing rule exist. A detected molecule answers a narrower question than whether a person could drive safely.
The authors used fold changes greater than 2 or below 0.5 to identify changes beyond their chosen uncertainty criterion. That approach compares a person with their own earlier measurement; a single specimen has no such baseline. The criterion should not be recast as a statistically validated boundary between impaired and unimpaired drivers.
Related reading: how edible and inhaled cannabis differ in timing.
Primary research
Jennifer L Berry; Ashley Brooks-Russell; Tara M Lovestead; Kavita M Jeerage. The detection of cannabinoids in breath after ingestion of cannabis-infused edibles. Journal of Analytical Toxicology (2025). DOI: 10.1093/jat/bkaf063.
Bibliographic correction: Correction to the primary article (2026), correcting the first author’s name to Jennifer L. Berry.
