Most e-cigarettes contain nicotine however, there are some nicotine-free e-liquids.
Nicotine concentrations vary from very low to more than is found in tobacco cigarettes.
Many e-cigarette products use “free-base” nicotine. However, higher nicotine concentrations of free-base nicotine are reported to cause “aversive user experiences.”
Newer devices, (e.g., Juul) contain protonated nicotine, derived from nicotine salts in tobacco.
Manufacturers claim that the salt-based solution plus additives can deliver higher levels of nicotine with less throat irritation and a more “satisfying experience” for the user.3 Each Juulpod contains 0.7 mL of a 59 mg/mL nicotine solution, the equivalent of about 20 tobacco cigarettes.9 Juul is reported to have the highest nicotine content available in the U.S. (two to ten times the nicotine concentration of most other e-cigarettes).