Nicotine Use DisorderPhase 1NCT03635333

Effects of E-Cigarette Flavors on Adults TCORS 2.0

A Phase 1 study testing Nicotine and Flavor in people with Nicotine Use Disorder, run by Yale University at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

This study looks at the effects of flavors when administered with nicotine in e-cigarettes in younger and older adult cigarette smokers. Read more about this study

Who is it for?: Ages 21 to 50 years
Conditions the study is for: Nicotine Use Disorder
What is being tested?: Nicotine and Flavor
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 130 participants
Where: 1 siteUnited States
Study dates: 14 May 2019to 12 Jul 2023
Phase: Phase 1
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 21 to 50 years
All sexes
No healthy volunteers
Adult

Who may be able to join

Ages 21-34 years or 35 -50 years
Able to read and write
Smoking >/= 1 cigarettes or cigars/day
Willing to abstain from regular smoking for 2 weeks and use only e-cigarettes
Not seeking treatment to stop smoking

Who cannot join

Daily use of other drugs including prescribed psychoactive drugs
Any significant current medical or psychiatric condition
Known hypersensitivity to propylene glycol
Pregnant or lactating females

Trial locations and contacts

1 site in 1 country.

United States1 site

CMHC, Substance Abuse Center
New Haven, Connecticut, 06519

Other trials in United States

About this study

Official title: Effects of E-Cigarette Flavors on Adults

This study looks at the effects of flavors when administered with nicotine in e-cigarettes in younger and older adult cigarette smokers.

Read the detailed description

This study looks at the effects of flavors when administered with nicotine in e-cigarettes in younger and older adult cigarette smokers. Regular cigarette smokers who do not want to quit smoking will be asked to complete 3 lab sessions in which they will use an e-cigarette and complete questionnaires. This will be followed by a two-week period where participants are asked to stop using cigarettes and other tobacco products and to only use the e-cigarettes provided. Researchers will examine the influence of flavors (sweet, cool, tobacco) on reward (liking/wanting) from e-cigs containing one of two nicotine concentrations (6 mg/ml, 18 mg/ml) following acute tobacco abstinence.

As of October 2020, this protocol was updated in which an additional lab session was added. Participants are to complete 4 lab sessions in which they will use an e-cigarette and complete questionnaires. In each individual lab session, they will sample one of the following four e-liquids: cherry, vanilla, menthol, tobacco. Additionally, participant age range was shifted to 21-50 with the younger condition being 21-34 and older being 35-50 and cigarette requirement was at least 1 cigarette/day at this time to be more representative of current persons who smoke.

Conditions: Nicotine Use Disorder
Being tested: Nicotine, Flavor
Medical subject headings: Tobacco Use Disorder

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

NicotineDrug
Nicotine level (6 or 18 mg)
FlavorDrug
Flavor of e-juice (tobacco, menthol, cherry, vanilla)

Study groups in NCT03635333
Study group	Role	What they receive
Low nicotine, tobacco	Experimental	6 mg nicotine combined with tobacco flavored e-juice Receives: Drug: Nicotine; Drug: Flavor
Low nicotine, menthol	Experimental	6 mg nicotine combined with menthol flavored e-juice Receives: Drug: Nicotine; Drug: Flavor
Low nicotine,cherry	Experimental	6 mg nicotine combined with cherry flavored e-juice Receives: Drug: Nicotine; Drug: Flavor
High nicotine, tobacco	Experimental	18 mg nicotine combined with tobacco flavored e-juice Receives: Drug: Nicotine; Drug: Flavor
High nicotine, menthol	Experimental	18 mg nicotine combined with menthol flavored e-juice Receives: Drug: Nicotine; Drug: Flavor
High Nicotine, cherry	Experimental	18 mg nicotine combined with cherry flavored e-juice Receives: Drug: Nicotine; Drug: Flavor
Low Nicotine, Vanilla	Experimental	6 mg nicotine combined with vanilla flavored e-juice Receives: Drug: Nicotine; Drug: Flavor
High Nicotine, Vanilla	Experimental	18 mg nicotine combined with vanilla flavored e-juice Receives: Drug: Nicotine; Drug: Flavor

What is being measured

The primary outcome is the main question the study is designed to answer.

Change Score in Liking/Wanting of E-cigarette
The Labeled Hedonic Scale (LHS; Lim et al., 2009) will be used to ask about liking and wanting of the e-cigarette (one item VAS scale [range -100 to 100] with ratings from most disliked sensation imaginable to most liked sensation imaginable with higher values indicating greater liking)
Measured: Baseline (+10 minutes) to end of lab session (+40 minutes)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

14 May 201912 Jul 2023

First posted17 Aug 2018
Study start14 May 2019
Primary completion12 Jul 2023
Study completion12 Jul 2023

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Nicotine Use DisorderStudies of the same condition, open and under way.
More trials run by Yale UniversityThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 1
Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind
Who is masked: Participant, Care provider
Enrolment: 130 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT03635333
Sponsor's protocol ID: 2000023077-2
Other IDs: 2U54DA036151-06
Status last verified: Dec 2025
First submitted: 13 Aug 2018
Last updated: 19 Dec 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: No
FDA-regulated device: No

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Nicotine Use Disorder trials

Study at a glance

From the registry record, last updated by the sponsor on 19 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Effects of E-Cigarette Flavors on Adults
ClinicalTrials.gov ID: NCT03635333
Acronym / sponsor ID: 2000023077-2
Conditions: Nicotine Use Disorder
Phase: Phase 1
Study type: Interventional
Recruitment status: Completed
Enrolment: 130 participants (actual)
Lead sponsor: Yale UniversityUniversity, hospital or other
Collaborators: National Institute on Drug Abuse (NIDA)
Study start: 14 May 2019 (actual)
Primary completion: 12 Jul 2023 (actual)
Study completion: 12 Jul 2023 (actual)
First posted: 17 Aug 2018 (actual)
Results: Posted 19 Dec 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

This study looks at the effects of flavors when administered with nicotine in e-cigarettes in younger and older adult cigarette smokers.

Detailed description

Study design

Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind (participant, care provider)
Number of arms: 8

Arm	Type	Receives
Low nicotine, tobacco	Experimental	Drug: Nicotine, Drug: Flavor6 mg nicotine combined with tobacco flavored e-juice
Low nicotine, menthol	Experimental	Drug: Nicotine, Drug: Flavor6 mg nicotine combined with menthol flavored e-juice
Low nicotine,cherry	Experimental	Drug: Nicotine, Drug: Flavor6 mg nicotine combined with cherry flavored e-juice
High nicotine, tobacco	Experimental	Drug: Nicotine, Drug: Flavor18 mg nicotine combined with tobacco flavored e-juice
High nicotine, menthol	Experimental	Drug: Nicotine, Drug: Flavor18 mg nicotine combined with menthol flavored e-juice
High Nicotine, cherry	Experimental	Drug: Nicotine, Drug: Flavor18 mg nicotine combined with cherry flavored e-juice
Low Nicotine, Vanilla	Experimental	Drug: Nicotine, Drug: Flavor6 mg nicotine combined with vanilla flavored e-juice
High Nicotine, Vanilla	Experimental	Drug: Nicotine, Drug: Flavor18 mg nicotine combined with vanilla flavored e-juice

Who may qualify

Ages: 21 to 50 years
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult

Key inclusion criteria (5 listed)

Ages 21-34 years or 35 -50 years
Able to read and write
Smoking >/= 1 cigarettes or cigars/day
Willing to abstain from regular smoking for 2 weeks and use only e-cigarettes
Not seeking treatment to stop smoking

Key exclusion criteria (4 listed)

Daily use of other drugs including prescribed psychoactive drugs
Any significant current medical or psychiatric condition
Known hypersensitivity to propylene glycol
Pregnant or lactating females

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
NicotineNicotine level (6 or 18 mg)	Drug	High Nicotine, Vanilla, High Nicotine, cherry, High nicotine, menthol, High nicotine, tobacco, Low Nicotine, Vanilla, Low nicotine, menthol, Low nicotine, tobacco, Low nicotine,cherry
FlavorFlavor of e-juice (tobacco, menthol, cherry, vanilla)	Drug	High Nicotine, Vanilla, High Nicotine, cherry, High nicotine, menthol, High nicotine, tobacco, Low Nicotine, Vanilla, Low nicotine, menthol, Low nicotine, tobacco, Low nicotine,cherry

Primary outcome

Change Score in Liking/Wanting of E-cigarette
Time frame: Baseline (+10 minutes) to end of lab session (+40 minutes)
The Labeled Hedonic Scale (LHS; Lim et al., 2009) will be used to ask about liking and wanting of the e-cigarette (one item VAS scale [range -100 to 100] with ratings from most disliked sensation imaginable to most liked sensation imaginable with higher values indicating greater liking)

Results and safety

Results posted to the registry on 19 Dec 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
High Nicotine	63	58
Low Nicotine	67	56

Primary outcome: Change Score in Liking/Wanting of E-cigarette

Time frame: Baseline (+10 minutes) to end of lab session (+40 minutes). Least squares mean (Standard Error). Unit: units on scale

Measure	Low Nicotine, Tobacco n = 53	Low Nicotine, Menthol n = 53	Low Nicotine,Cherry n = 53	High Nicotine, Tobacco n = 54	High Nicotine, Menthol n = 54	High Nicotine, Cherry n = 55	Low Nicotine, Vanilla n = 52	High Nicotine, Vanilla n = 53
Value	-1.06 (4.68)	-5.59 (4.67)	-7.14 (4.8)	-7.63 (4.72)	8.41 (4.73)	0.42 (4.78)	4.77 (4.65)	5.48 (4.74)

Population analysed: The study started in May 2019 and the study was active between May 2019 and October 2020 and 9 participants were enrolled. However, due to study changes communicated previously, analyses only reflect enrolled participants who completed the study following the study protocol change (i.e., addition of a laboratory session in October 2020). Randomized non-starters were excluded from analyses (n=8, 5 low nicotine, 3 high nicotine). Those who completed at least one lab had data included in analyses

Adverse events

Time frame: Adverse events for each participant were recorded from the start of their participant to completion (6 month follow up phone call), on average 6 months.. Other adverse events reported at 1% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Vanilla Low Nicotine Group (6mg/ml)	0 of 55 (0%)	0 of 55 (0%)	0 of 55
Vanilla High Nicotine Group (18mg/ml)	0 of 52 (0%)	0 of 52 (0%)	0 of 52
Cherry Low Nicotine Group (6mg/ml)	0 of 51 (0%)	1 of 51 (2%)	0 of 51
Cherry High Nicotine Group (18mg/ml)	0 of 51 (0%)	0 of 51 (0%)	0 of 51
Tobacco Low Nicotine Group (6mg/ml)	0 of 59 (0%)	1 of 59 (1.7%)	0 of 59
Tobacco High Nicotine Group (18mg/ml)	0 of 57 (0%)	0 of 57 (0%)	0 of 57
Menthol Low Nicotine Group (6mg/ml)	0 of 59 (0%)	0 of 59 (0%)	0 of 59
Menthol High Nicotine Group (18mg/ml)	0 of 56 (0%)	0 of 56 (0%)	0 of 56
Randomized Non-Starter Low Nicotine Group (6mg/ml)	0 of 8 (0%)	0 of 8 (0%)	0 of 8
Randomized Non-starter High Nicotine Group (18mg/ml)	0 of 6 (0%)	0 of 6 (0%)	0 of 6

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 19 Dec 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.

Related trials for Nicotine Use Disorder

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing Nicotine and Flavor in people with Nicotine Use Disorder, run by Yale University at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 19 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 19 Dec 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change Score in Liking/Wanting of E-cigarette (time frame: Baseline (+10 minutes) to end of lab session (+40 minutes)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03635333.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Dec 2025; AzTrials last refreshed its copy on 7 Nov 2026.