Although vaping is less harmful than smoking, it is still not risk-free. E-cigarettes heat nicotine (derived from tobacco), flavorings, and other compounds to form an aerosol that you inhale. Tobacco cigarettes contain more than 7,000 compounds, many of which are hazardous. People switching from cigarettes to e-cigarettes are likely to experience a new set of challenges including fewer alternatives for satisfying cravings and replacing the behavior patterns ingrained over time. Electronic cigarettes have been on the market for about 10 years but have recently gained popularity due to advertisements depicting attractive young people using the devices. In fact, according to a study published in the journal Addiction, almost one in five high school students report having used an electronic cigarette. The study also found that nearly one in three middle school students had tried an electronic cigarette. Because these products are not regulated by any federal agency, they can contain any amount of nicotine or no nicotine at all. There are also no regulations regarding the quality of ingredients used to produce e-liquid, so some could be harmful if ingested. Electronic cigarettes may also function differently depending on how they are used. Some users claim that by changing the size of the bore (the hole through which smoke is drawn) of the device, they can customize the level of nicotine intake. However, the study authors note that there is little evidence supporting this practice.