A Phase 2 interventional study of d-cycloserine and Juul e-cigarette in Smoking Cessation and Harm Reduction, sponsored by Rose Research Center, LLC. Completed at 2 sites in United States. Open to participants aged 22 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-01-20.
Sponsored by Rose Research Center, LLC · Phase 2, Interventional, and Treatment
This study will evaluate the effects of a reward devaluation strategy, which has been researched in the past, combined/augmented with the medication d-cycloserine in assisting smokers to switch from combustible cigarette (CC) to Juul.
1,581 studies on the registry are indexed under Smoking Cessation; 198 are open to participants now.
This study's enrollment of 25 is below the median of 164 across 1,423 interventional studies indexed under Smoking Cessation.
Browse Smoking Cessation studies →Rose Research Center, LLC is the lead sponsor of 13 studies on the registry; none are open to participants now.
Of its 8 completed or terminated interventional studies of FDA-regulated products, 3 (38%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Use of any of these products in the past 30 days:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
d-cycloserine (DCS) 100 mg taken orally, once a day for six weeks. There will be a 50 mg dose taken the afternoon/evening prior to the first switch date (after enrollment) to ensure serum levels of the medication are available for the first switch to e-cigarette attempt. Participants will be instructed to use the Juul as often as they like during the 12 week period, and to switch completely to the Juul within 1 week. If, however, they do smoke any combustible cigarettes (CC), they will also be instructed to use the Juul immediately before each CC to relieve their craving as much as possible before smoking their usual brand. The Juul will also be the first product that they are instructed to use each morning. Smokers will be told to try to completely substitute Juul for CCs by the end of the first week of use.
Drug: d-cycloserine · Other: Juul e-cigarette
d-cycloserine (DCS) 100 mg taken orally, once a day for six weeks.
Juul use as often as the participant likes for 12 weeks.
Smoking Abstinence based on Self-Report
Complete switching from combustible cigarette use at each time point will be defined by a self-report of no cigarette smoking (not even a puff) since the prior session.
Time frame: During weeks 3-6 and 9-12 post-switching date.
Smoking Abstinence based on Expired Air Carbon Monoxide (CO)
Complete switching from combustible cigarette use at each time point will be confirmed by an expired air CO reading of less than 5 ppm.
Time frame: End of Week 6, End of Week 12
Reduction in Cigarettes Per Day
Reduction in the number of reports cigarettes smoked per day over the previous seven days (at each time point) compared to baseline.
Time frame: Week 6, Week 12, Six-Month Follow-Up
Reduction in Expired Air Carbon Monoxide (CO)
Reduction in Expired Air Carbon Monoxide (CO) compared to baseline.
Time frame: End of Week 6, End of Week 12
Change in rewarding effects for cigarettes and e-cigarettes at 6 weeks post switch
o assess subjective satisfaction and other perceived rewarding or aversive effects accompanying e-cigarette use and combustible cigarette use using the modified (e-Cigarette) Cigarette Evaluation Questionnaire. This questionnaire contains five subscale scores: smoking satisfaction (satisfying, tastes good, enjoy smoking), psychological rewards (calms down, more awake, less irritable, helps concentrate, reduces hunger), aversion (dizziness, nauseated), enjoyment of respiratory tract sensations (single-item assessment), craving reduction (single-item assessment). Participants will be asked to assess the 12 items of the questionnaire on a 7-point scale, ranging from "1-not at all" to "7-extremely".
Time frame: End of Week 6
Tolerability of daily use of D-cycloserine in conjunction with Juul
The frequency and severity of adverse events will be tabulated as well as the likelihood of their causal relationship to treatment.
Time frame: Week 2, Week 6, Week 8, Week 12
Plan to share: No
No publications or documents are linked to this record.
This study is completed, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Cycloserine
Rose Research Center, LLC