Compensatory Behavior of E-cig Users in Response to Reduced Nicotine E-liquids

The goal of this clinical trial is to learn if low nicotine eliquids work to reduce exposure to nicotine, in addicted ecig users, without increasing consumption of other harmful constituents. The main questions it aims to answer are: * Does switching to lower nicotine eliquids change the vaping behavior of addicted ecig users? * Does switching to lower nicotine eliquids reduce the amount of nicotine consumed? Researchers will compare ecig users who switch from a higher to lower nicotine eliquid to a control group that does not switch. Participants will: * Complete history of tobacco use and nicotine addiction questionnaires * Switch from higher to lower nicotine product or control for 15 days * Complete daily questionnaires to report craving, mood and nicotine withdraw For one full day under each nicotine condition, participants will: * record puffing behavior using a topography monitor * wear a sensorized shirt that measures the depth and duration of inhalation, and * collect a saliva sample at the end of each day