They are not FDA approved, and the only ones regulating themselves are themselves... All our information saying they are 'safe' products come from the companies selling them...
Any extensive research found states, they are basically using anti-freeze to congeal the flavoring and nicotine together... From a former e-cigarette smoker the cigarettes break on you a lot and from time to time shove huge quantities of nicotine into your mouth... (In liquid form).
This e-cigarette fad is just insanity... The Govt. bans flavored cigarettes because children would be more inclined to use them. Now we have a product with flavors such as Monster (Energy drink), Cotton Candy, and Cinnamon... Those are 3 of the flavors I used to personally smoke so I know for a fact the're out there and they are called that...
And on top of that nicotine is a poison... So best case scenario you are still killing yourselves...