for people ages 21 years and up (full criteria)
Healthy Volunteers
healthy people welcome
study started
estimated completion
Principal Investigator
by Gideon St. Helen (ucsf)



This study will examine the short-term cardiovascular (CV) effects of e-cigarette device power in a randomized, crossover clinical and behavioral pharmacology study of experienced adult e-cigarette users (N=21). The specific aim is to determine the impact of e-cigarette power on nicotine pharmacology, systemic exposure to toxic volatile organic compounds (VOCs), and short-term cardiovascular effects.


This is a single-site, randomized, crossover study of experienced adult e-cigarette users to assess nicotine exposure, toxicant exposure, and the short-term CV effects of e-cigarette power. Three power levels will be assessed on all participants: 10, 15, and 20 watts. Hypothesis 1a: Systemic nicotine exposure and subjective measures of sensation in the throat, reward, and satisfaction will increase with increasing power in the e-cigarette device. Hypothesis 1b: Mercapturic acid metabolites of volatile organic compounds (VOCs), particularly acrolein, will increase with e-cigarette power. Hypothesis 1c: CV effects increase with higher power, and are manifested as changes in hemodynamic parameters, hormonal release, and biomarkers of endothelial function, platelet activation, inflammation, and oxidative stress.


Cardiovascular Risk Factor Nicotine Dependence E-Cigarettes Vaping E-Cig Mods Tobacco Use Disorder Electronic Cigarette


You can join if…

Open to people ages 21 years and up

  • Use e-cigarettes on at least 25 days in the past 30 for at least 3 months and have not used another tobacco product in the past 30 days
  • Healthy on the basis of medical history and limited physical examination (screening visit), as described below:
  • Heart rate < 105 beats per minute (BPM)*
  • Systolic Blood Pressure < 160 and > 90*
  • Diastolic Blood Pressure < 100 and > 50*
  • Body Mass Index (BMI) ≤ 38.0 (at investigator's discretion for higher BMI if no other concurrent health issues)

*Considered out of range if both machine and manual readings are above/below these thresholds.

  • Any race/ethnicity

You CAN'T join if...

  • Used tobacco products other than e-cigarettes in past 30 days
  • Expired carbon monoxide of over 5 ppm at screening
  • The following unstable medical conditions:
  • Heart disease
  • Uncontrolled hypertension
  • Thyroid disease (not hypo or hyper, controlled with medication)
  • Diabetes
  • Hepatitis B or C or Liver disease
  • Glaucoma
  • Prostatic hypertrophy
  • Psychiatric conditions:
  • Current or past schizophrenia, and/or current or past bipolar disorder
  • Adult onset attention deficit hyperactivity disorder (ADHD) (if being treated)
  • Participants with current or past depression and/or anxiety disorders will be reviewed by the study physician and considered for inclusion
  • Psychiatric hospitalizations are not exclusionary, but study participation will be determined as per study physician's approval
  • Drug/Alcohol Dependence:
  • Alcohol or illicit drug dependence within the past 12 months with the exception of those who have recently completed an alcohol/drug treatment program
  • Positive toxicology test at the screening visit (THC & prescribed medications okay)
  • Opioid replacement therapy
  • Positive urine cannabis is not exclusionary but participant must report use of cannabis in any form on not more than 2 times per week to be eligible
  • Psychiatric medications:
  • Current regular use of any psychiatric medications with the exception of Selective Serotonin Reuptake Inhibitor (SSRI) and serotonin-norepinephrine reuptake Inhibitor (SNRIs) and current evaluation by the study physician that the participant is otherwise healthy, stable, and able to participate.
  • Medications
  • Use of medications that are inducers of nicotine metabolizing enzyme CYP2A6 (Example: rifampicin, dexamethasone, phenobarbital, and other anticonvulsant drugs).
  • Concurrent use of nicotine-containing medications
  • Other/Misc. Chronic Health Conditions
  • Oral thrush
  • Fainting
  • Untreated thyroid disease
  • Other "life threatening illnesses" as per study physician's discretion
  • Pregnancy
  • Pregnancy (self-reported and urine pregnancy test)
  • Breastfeeding (determined by self-report)
  • Concurrent participation in another clinical trial
  • Inability to communicate in English
  • Planning to quit smoking or vaping within the next 60 days


  • Zuckerberg San Francisco General Hospital accepting new patients
    San Francisco California 94110 United States
  • University of California, San Francisco accepting new patients
    San Francisco California 94143 United States

Lead Scientist at University of California Health


accepting new patients
Start Date
Completion Date
University of California, San Francisco
Study Type
Last Updated