An electronic cigarette or e-cigarette is a handheld electronic device that vaporizes a flavored liquid. The user inhales the vapor. Using e-cigarettes is often called vaping. The fluid in the e-cigarette, called e-liquid, is usually made of nicotine, propylene glycol, glycerine, and flavorings.
The health risks of e-cigarettes are uncertain. While they are safer than tobacco cigarettes, the long-term health effects are not known. There is evidence they can help some people quit smoking although they have not been proven to work better than safer, regulated nicotine replacement products. Their value in tobacco harm reduction is unclear, with tentative evidence that they could help lower tobacco-related death and disease. No serious adverse effects have been reported in trials. Less serious adverse effects include throat and mouth irritation, vomiting, nausea, and coughing. Non-smokers who use nicotine-containing e-liquids risk addiction to nicotine.
E-cigarettes create an aerosol, commonly called vapor, generally containing nicotine, flavors, glycerol and propylene glycol. Its composition varies across and within manufacturers, and depends on the contents of the liquid, the electrical power of the device, and user behavior, among other factors. The vapor can contain toxicants and traces of heavy metals at levels permissible in inhalation medicines, and some potentially harmful chemicals not found in tobacco smoke at concentrations permissible by workplace safety standards. However, chemical concentrations may exceed the stricter public safety limits.
The modern e-cigarette was invented in 2003 by Chinese pharmacist Hon Lik, and as of 2015 most e-cigarettes are made in China. Since they were first sold in 2004 their global use has risen exponentially. In the UK users have increased from 700,000 in 2012 to 2.6 million in 2015. In the United States e-cigarettes are used by a significant portion of young people. and adults. Reasons for using e-cigarettes involve trying to quit smoking, reduce risk, or save money, though many use them recreationally. A majority of users still smoke tobacco, causing concerns that dual use may "delay or deter quitting". About 60% of UK users are smokers and roughly 40% are ex-smokers, while use among never-smokers is "negligible". Because of overlap with tobacco laws and medical drug policies, e-cigarette legislation is debated in many countries. A European directive in 2016, set limits for liquids and vaporizers, ingredients, and child-proof liquid containers. As of August 2016, the US FDA extended its regulatory power to include e-cigarettes. As of 2014, there were 466 brands of e-cigarettes with global sales of around $7 billion.