A Public Participation Forum for the FDA Center for Tobacco Products and its Federal Advisory Committee (TPSAC)

And some users flatly consider them great smoking-cessation devices — a combination that allows users to wean themselves off of nicotine and satisfy the tactile practice of using their hands and mouths in social settings, even when others are smoking traditional cigarettes.

E-cigarette flavoring can be loaded with anywhere from 0 to 24 milligrams of nicotine to provide the nicotine jolt that smokers say they get with traditional tobacco products.

Gradually lowering that level, and getting away from the harmful effects of tars and carbon   monoxide of tobacco-burning cigarettes is e-cigarette smokers’ overriding claim for it being a great way to quit smoking.

But e-cigarettes’ effectiveness as a smoking-cessation tool has not yet been proven, and e-cigarette makers and sellers are very careful about making strong claims.

The U.S. Food and Drug Administration is studying e-cigarettes and their effects, but health experts say it will likely be years before research will bear any real findings.