While electronic cigarettes are seen by many as a way to wean off traditional cigarettes, new research suggests that the "e" version may be just as addictive as its smoky counterpart.

E-cigarettes do not burn tobacco, but they do include nicotine, flavorings and other substances. While that nicotine could potentially make them highly addictive, in fact "not all nicotine is created equal," according to a statement, and previous studies had not determined what kind the e-cigarettes contained.

In a new study appearing in the American Chemical Society journal Chemical Research in Toxicology, researchers set out to determine the predominant type of nicotine found in commercial samples of the liquids used with e-cigarettes.

Their findings revealed that the nicotine was mainly found in its most addictive form, known as "free-base" -- the only one of three kinds that is actually absorbed by the body.The concentration of that nicotine varied, they found, and did not always match the labels.