As @thuytienlaco and @amandaally1029 stated, e-cigarettes are regulated by the FDA. In Aug 2016 the FDA finalized the rule extending CTP’s regulatory authority to cover all tobacco products, including electronic nicotine delivery systems (ENDS) that meet the definition of a tobacco product.

As per 21 CFR Parts 201, 801, and 1100
Tobacco product is defined as” any product made or derived from tobacco that is intended for human consumption, including any component, part, or accessory of a tobacco product (except for raw materials other than tobacco used in manufacturing a component, part, or accessory of a tobacco product)”

There was in interesting article in the NY Times about developing a comprehensive plan for tobacco and nicotine regulation. The FDA will encourage companies to reduce nicotine levels so that they are not addictive. However, the addictive aspect is how big tobacco makes their profits and business model. I’m not sure how tobacco will take to that encouragement. https://www.nytimes.com/2017/07/28/health/electronic-cigarette-tobacco-nicotine-fda.html?mcubz=3

I agree that an e-cigarette would be considered a class III medical device since it is releasing a drug. The primary mode of action is to release nicotine.

The FDA expects that most ENDS products that companies submit for market authorization will go down the Premarket Tobacco PMTA pathway, which does not require a comparison to a predicate product and will determine when it is necessary to have a clinical trial and when it is not necessary.

Reading up on this topic I found it really interesting that FDA considers EACH ENDS product with a differing flavoring variant or nicotine strength to be a different product. So the blueberry, cupcake, cherry, etc would all be considered different products and submitted as such. The FDA does say you can submit one premarket application but it does need to be broken down by product (each flavor). The more flavors, the more paperwork.

In regards to normal cigarettes, the Tobacco Control Act requires all new cigarettes to receive explicit approval from the FDA before being allowed on the market if they are a new product introduced after March 2011.