How cooling ingredients and menthol change the feel of nicotine e-liquids for adult vapers
Official title: Examining Appeal and Addiction Potential of Novel E-cigarette Constituents Among Adults
Run by Yale University · NCT05932745 · Data updated 2026-11-12
This project will test whether cooling chemicals (WS-3, WS-23) and menthol make nicotine e-liquids more appealing or habit-forming for adults who use e-cigarettes.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 66 (estimated) |
| Sponsor | Yale University Academic / other |
| Locations | 1 site (New Haven, Connecticut) |
| Status | Recruiting |
| Started | June 20, 2025 |
| Main results expected | August 2026 |
| Study ends | August 2026 |
| Registry record updated | June 16, 2026 |
| Trial ID | NCT05932745 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are adults (18+) who are current e-cigarette users with urine cotinine ≥200 ng/ml, willing to abstain from nicotine for two hours and to attend three lab visits in New Haven, CT.
✕Probably not a fit
People who do not vape, are pregnant or breastfeeding, have uncontrolled asthma, allergies to propylene glycol or flavorants, current nonprescription substance use (aside from allowed substances), or who dislike menthol are excluded and unlikely to benefit from participation.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
Sixty-six adults who currently use e-cigarettes will attend three in-person lab sessions and be exposed to a total of 18 different e-liquid conditions containing nicotine salt (~59 mg/ml). Participants are randomized to one of three menthol conditions across sessions (no menthol, low, high) and, within each session, sample combinations of WS-3 and WS-23 at varying concentrations in randomized order. During each exposure, participants will rate flavor intensity, coolness, sweetness, irritation/harshness, and bitterness using validated scales. The study uses strict eligibility (e.g., urine cotinine ≥200 ng/ml) and brief pre-session abstinence to ensure participants are current e-cigarette users.
Why it matters
Potential benefit: If successful, the results could help regulators and clinicians understand which cooling agents increase appeal or addiction risk and guide policies or advice to reduce harm.
How similar studies have gone: Prior work shows menthol can increase appeal and alter sensory perception linked to dependence, while synthetic coolants like WS-3 and WS-23 are less well-studied, so this study is partly confirmatory and partly novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * 18 years or older * Able to read and write * Some current e-cigarette use * Urine cotinine ≥200ng/ml * Willing to abstain from tobacco/nicotine use 2 hours prior to sessions Exclusion Criteria: * Current use of non-prescription substances besides nicotine, marijuana, alcohol * Any significant current medical or psychiatric condition * Known hypersensitivity to propylene glycol * Pregnant or lactating females * Uncontrolled asthma * Nut/e-liquid flavorant allergy * Current marijuana (tetrahydrocannabinol) vaping + E-cigarette or vaping use Associated Lung Injury (EVALI) symptoms * Dislike of menthol flavor
Where it's running
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JB Pierce Lab
New Haven, Connecticut, United States Recruiting
Study contacts
- Principal investigator: Suchitra Krishnan-Sarin, PhD — Yale University
- Study coordinator: Danielle Davis, PhD
- Email: danielle.davis@yale.edu
- Phone: 203-974-7607
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.