Breath tests reveal how cannabis and tobacco differently impact lungs
NCT ID NCT07694466
First seen Jul 10, 2026 · Last updated Sep 04, 2026 · Updated 2 times
Summary
This study compares the immediate effects of inhaling cannabis (either smoked or vaporized) versus tobacco cigarettes on lung health. Researchers will measure breath biomarkers—such as exhaled nitric oxide, volatile organic compounds, and other substances—to see how each substance affects the lungs. The study involves 12 healthy adults who are current recreational cannabis users and also smoke tobacco. Findings may help identify unique breath markers for cannabis versus tobacco exposure.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Cannabis (THC) and Tobacco
- What this could lead to
- If successful, this could help identify specific breath biomarkers that distinguish the lung effects of cannabis from tobacco, informing future health guidelines.
- What could go wrong
- This is a very small early-phase study (12 participants) and only measures immediate effects, not long-term health outcomes. Results may not apply to heavier or more diverse users.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Early phase 1
The earliest testing in people: a first look at safety, in a very small group.
- Participants
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About 12 people
The number the study aims to enrol. It can still change while the study runs.
- Expected to start
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Oct 2026
An estimate. Start dates often move.
- Expected to finish
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Jun 2027
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 55 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. English-speaking, 2. Literate adults, 3. Male or female, 4. Between the ages of 18 and 55, 5. Body Mass Index from 18.5 and 32.0 kg/m2, 6. Able to provide written informed consent and perform all study procedures, 7. Current recreational cannabis users - must report past 30-day cannabis use and at least 5 exposures in the past year (minimum use criteria); no limit on maximum use, 8. Past year history of vaporized or smoked cannabis use to intoxication, 9. Past 30-day use of combusted tobacco, 10. Not currently seeking treatment for cannabis, tobacco cigarettes, or other drug use, 11. If female, a negative pregnancy test and use of an effective form of contraception during study participation (e.g., oral contraceptive, abstinence, barrier method), 12. Negative urine drug test for drugs of abuse (other than cannabis) before every Laboratory Session, and 13. Otherwise, healthy as determined by the investigator based on medical history, physical examination, vital signs, laboratory chemistries (blood chemistry with liver function tests and hematology, urinalysis, and microscopic evaluation, 12-lead electrocardiogram). Exclusion Criteria: 1. Physiologic drug dependence on opioids, benzodiazepines, barbiturates, and/or alcohol that would require medical management, 2. Clinically significant acute medical problem (e.g., infection) or chronic medical problem requiring daily medication or ongoing medical care (e.g., hypertension, cardiovascular disease, diabetes, respiratory disorders \[e.g., asthma, COPD\]), 3. Existing or significant lung health problems that could interfere with the study, 4. Current or history of major psychiatric disorder that would limit the participant's ability to participate in the study (e.g., bipolar disorder), 5. Exclusive use of tobacco or cannabis through vapes and Electronic Nicotine Delivery Systems (ENDS) products, 6. Currently using daily prescription medications to manage medical conditions or any drug that could interfere with the study (as determined by the study physician), 7. Clinically significant abnormal ECG (as determined by study physician/cardiologist), 8. Clinically significant abnormal laboratory findings (e.g., liver function tests greater than 3x the upper limits of normal range), 9. History of seizure disorder, 10. Clinically significant history of head injuries requiring medical management or long-lasting sequelae.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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University of Kentucky
Lexington, Kentucky, 40508, United States
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