E-cigarettes are designed to be less offensive than the traditional cigarette, and manufacturers market the cig-alternative as a way to safely and effectively quit smoking.

E-cigarettes, or electronic cigarettes, are classified as a type of Electronic Nicotine Delivery System (ENDS). Products in this specific class deliver a liquid containing a mixture of nicotine, propylene glycol, glycerin, flavorings (sometimes) and other unknown ingredients to its users as a vapor instead of a harsher smoke. E-cigarettes are now manufactured to look like everyday items, such as pens or USB memory sticks. There are hundreds of different e-cigarette brands currently available to consumers.

E-cigarettes were originally designed by a Beijing pharmacist, Hon Lik, in 2003, making the product a relatively new phenomenon. Lik was a heavy cigarette smoker, consuming about three packs of day of the harmful tobacco smoke. Lik’s father was also an avid smoker who died of lung cancer.

Lik’s purportedly safer-than-cigarettes alternative hit the US and European markets in 2007, and manufacturer Ruyan immediately began promoting the product as a way to safely quit smoking. But just one year later, the World Health Organization (WHO) was already questioning the electronic device’s presumed safety. The organization urged marketers of the product to remove claims that it was a safe and effective way to quit smoking because no scientific evidence was available to support those claims.

The National Institute on Drug Abuse also stated that little is actually known about the health risks of e-cigarettes, even though they are marketed as a safer alternative to traditional cigarettes, which everyone now knows are harmful to our health.

On May 5, 2016, the Food and Drug Administration (FDA), which has not approved e-cigarettes, announced it was going to begin regulating e-cigarettes along with other tobacco products; a move that the American Lung Association (ALA) had long called for. The ALA claims that the action is especially important as e-cigarettes have given rise to interest among youth in the U.S., as evidenced in a 900 percent increase in their use among high school students from 2011 to 2015.

How Do E-Cigarettes and Vape Pens Work?

Electronic cigarettes are more popularly known as e-cigarettes, e-cigs or vape pens. They include vape pens, vaporizers, e-pens, e-pipes, e-hookah and e-cigars, all classified as electronic nicotine delivery systems (ENDS).

E-cigarettes are made up of several parts or components, including:
  • E-liquids
  • A glass or plastic vial container of e-liquid
  • Refillable cartridges
  • Atomizers (a device for emitting liquid)
  • Batteries or other power source
  • Tank systems
  • Drip tips
  • Cartomizers (disposable cartridge with atomizer already built in) and clearomizers (a cartomizer, atomizer and cartridge all-in-one)
  • Digital display or lights to adjust settings
  • Flavorings
  • Programmable software

The three main elements of an e-cigarette are:

e-cigarette cartridge


Holds the liquid mixture with varying dosages of nicotine, flavorings and chemicals

e-cigarette heating device

Heating Device

To convert the liquid to a vapor (vaporizer)

e-cigarettes power source

Power Source

Usually a battery

When the user puffs on the mouthpiece of the e-cigarette, the battery-operated heating element is activated, vaporizing the e-liquid stored in the refillable cartridge and releasing an aerosol or vapor, which is then inhaled. This is called vaping.

Who is Using E-Cigarettes and Vape Pens?

While e-cigarettes and vaping are marketed as the safer alternative to traditional cigarettes and an effective way to quit smoking, data from a National Health Interview Survey in 2015 showed that 3.2 percent of adults who had never smoked cigarettes have opted to try e-cigarettes. That percentage was highest among users aged 18 to 24-years-old at 9.7 percent, and declined as age increased.

Other results from the survey showed:
  • Men were more likely to try e-cigarettes than women

  • More than 20% of adults aged 18 – 24 had tried an e-cigarette, and that percentage steadily declined with age

  • More than half of current cigarette smokers who tried to quit smoking in the past year tried e-cigarettes

  • 20.3% of those individuals were still using e-cigarettes

  • Overall, in 2014, 12.6% of adults had tried an e-cigarette at least once

  • About 3.7% of all adults still used e-cigarettes every day or some days

  • Current or former cigarette smokers who had quit smoking within the past year were more likely to use e-cigarettes than former smokers who quit smoking over one year ago and those who had never smoked

What is in e-liquid?

e-liquid components
Common components found in E-liquids

Because e-cigarettes are not an FDA-approved product, and because hundreds of different brands, including thousands of different flavors, are available to consumers, it is almost impossible for anyone to know what all manufacturers are actually adding to the mix in the composition of their e-liquids. Since the FDA’s announcement in 2016 that it will now be overseeing all tobacco products, including e-cigarettes, manufacturers of e-cig products had to register with the FDA, but then they were given an additional two years to submit their applications to remain in the market of vaping.

While it’s still not entirely clear how many ingredients and what ingredients make up any brand of e-liquid in an e-cigarette, it is known that most e-cigarettes, even the ones claiming to be nicotine-free, contain nicotine. Some studies have also found that the vaping process itself can form a dangerous substance known as formaldehyde, and another study raised the question of whether a substance used in antifreeze is also used in certain leading brands of e-liquid.

What is Nicotine and is it Harmful?

Nicotine is an addictive substance extracted from tobacco. Nicotine is what provides smokers and vapors alike with the feel-good, reinforcing properties that cause people to continue the act of smoking or vaping, even if they want to quit. E-cigarettes were designed to give people the same pleasurable feelings of smoking, but with fewer toxic chemicals like those produced by burning tobacco.

But nicotine all on its own is still potentially harmful to a user’s health. Because of its highly addictive properties, it is also thought to be a gateway substance to other addictive substances. Although some e-cigarettes are marketed as being nicotine-free, a study conducted by the FDA in 2009 found low amounts of nicotine in cartridges labeled otherwise. Another study in 2014 also found that amounts of nicotine listed on e-liquid packaging can be inconsistent and misleading. And newer e-cig products, such as those with tanks, are able to deliver greater concentrations of nicotine, increasing a user’s exposure and leading to heightened levels of addiction.

Open Pill Bottle Scattered on Table with Alcohol
Nicotine is thought to be a gateway to other addictive substances, like drugs and alcohol

Nicotine in Children

In 2016, the Surgeon General issued a report finding that e-cigarettes are not safe. The report stated that the use of products containing nicotine in any form, including e-cigarettes, pose dangers (some with lasting consequences) especially to youth, pregnant women and fetuses. The report suggested e-cigarette side effects may be similar to those of other tobacco products.

Nicotine exposure during adolescence can cause addiction and can harm the developing adolescent brain.

The Surgeon General was especially concerned that e-cigarettes are marketed with an emphasis on flavors that can encourage e-cig use in youth and young adults. Prior to FDA regulation, e-cigarettes, unlike traditional cigarettes, were not subject to age and marketing restrictions. Today, the age requirement for purchasing e-cigarettes is 18.

Nicotine Deaths

The New York Times reported that it would take just a teaspoon of certain e-liquids to result in the death of a child if consumed.

Did You Know
The New York Times reported that it would take just a teaspoon of certain e-liquids to result in the death of a child if consumed.

The liquid is capable of resulting in acute nicotine toxicity if it comes into direct contact with a person’s skin or eyes, or if it’s ingested or even inhaled, especially in children, a pediatrician and an epidemiologist with the CDC, Dr. Kevin Chatham-Stephen, said.

According to the American Association of Poison Control Centers, 585 exposures occurred from January 1, 2017, to March 31, 2017, alone. In 2014, more than half of the reported exposures occurred in children under six years of age.

In December 2014, a one-year-old child died from exposure to liquid nicotine. His was the first e-liquid-related death in the U.S. But the numbers of reports for child exposures, according to the National Poison Data System, are rapidly increasing. In 2014, the US Centers for Disease Control and Prevention (CDC) reported a significant increase in calls to poison control centers associated with e-cigarette use, up from approximately one call per month in 2010 to about 200 calls per month in the beginning of 2014.

A study conducted by the American Academy of Pediatrics in 2016 found the following:
  • From January 2012 to April 2015, the National Poison Data System received 29,141 calls for exposure to nicotine and tobacco products in children under six. That equates to an average of 729 children per month

  • E-cigarettes accounted for 14.2% of exposures

  • During the study, the monthly number of e-cigarette exposures increased by 1492.9%

  • Children under two years of age accounted for 44.1% of e-cig exposures

  • E-cigarette exposures in children were 5.2 times more likely to be admitted to a medical facility

  • Such exposures were also 2.6 times more likely to have a more severe outcome than those exposed to traditional cigarettes

  • One death occurred from liquid nicotine exposure

But it’s not just children that can succumb to nicotine poisoning. The Times also reported that less than a tablespoon of e-liquids at higher concentration levels is capable of killing an adult, and one person was reported to have cardiac problems following absorption of the liquid through her skin.

Two suicides by liquid nicotine have been reported as well; one in the US in 2011, and Britain’s first suicide by an e-liquid solution in 2015.

Other Chemicals

An analysis published by the New England Journal of Medicine found that it was possible for formaldehyde, a known cause of cancer, to be formed during the vaping process.

It’s unknown how formaldehyde affects the lungs and respiratory system, but it is classified by the International Agency for Research on Cancer as a group 1 carcinogen. Therefore, the long-term risk of vaping, assuming that the user is inhaling formaldehyde-releasing agents, could be associated with an incremental lifetime cancer risk that is five to fifteen times greater than the risk associated with long-term smoking at one pack per day.

Additionally, a separate 2014 study of e-cigarettes conducted by the FDA, revealed that two leading brands may contain a substance known as diethylene glycol. Diethylene glycol is an ingredient used in antifreeze and is toxic to humans.

The study also found that certain tobacco-specific nitrosamines (a chemical substance capable of causing cancer) were detected in half of all of the tested samples. And other tobacco-specific impurities that are suspected of also being harmful to humans were discovered in the majority of the tested samples.

E-Cigarette Flavorings

A study conducted by Harvard University researchers found that many different flavorings added to e-liquids in e-cigarettes contain chemicals that may be harmful to users’ long-term health.

Some flavors included in the study were: Classic, Menthol, Cherry Crush, Java Jolt, Pina Colada, Vanilla Bean, Bad Apple, Iced Berry, Banana, Pomegranate, Peach Pit, Watermelon, CooCoo Coconut, Pineapple Punch, Carmel Popcorn, Bubble Gum, Cotton Candy and Tutti Frutti.

Results showed that at least one of the three common flavoring chemicals, diacetyl, 2,3 pentanedione or acetoin, was present in 47 of the 51 flavors tested. Those results include e-cigarette flavors such as classic and menthol.

  • Diacetyl was found in 39 of 51 flavors tested

  • 2,3-pentanedione was found in 23 of the 51 flavors

  • Acetoin was found in 46 of the 51 flavors

  • Diacetyl and 2,3-pentanedione were present simultaneously in 21 flavors tested

  • 2,3-pentanedione and acetoin were found simultaneously in 22 flavors

  • Diacetyl and acetoin were found simultaneously in 38 flavors

Health concerns related to the inhalation of these substances are well-recognized by the Occupational Safety and Health Administration (OSHA) and the flavoring industry. The Federal Emergency Management Agency (FEMA) recommends a warning be included for “any compounded flavors (liquid, dry or powdered) containing any flavoring substances… in any concentrations if the compounded flavor or any of its individual flavoring substances will be heated during processing.”

But unlike the flavor industry, and OSHA and FEMA efforts, the study concluded that the e-cigarette industry did not contain any similar notifications or warnings.

In 2014, a researcher at the Onassis Cardiac Surgery Center, Konstantinos Farsalinos, conducted a study that showed 74 percent of 159 flavors sampled contained the troubling chemical, diacetyl, and that nearly half of that percentage contained levels of exposure to e-cigarette users that exceeded workplace limits for recommended safe inhalation of the substance.

Additionally, in 2014, the National Institutes of Health reported that e-cigarette users could be adversely affected when using cinnamon flavorings, found to contain chemicals such as cinnamaldehyde, which can be toxic.

Flavor Recalls

With hundreds of brands of e-cigarettes, over 7,000 different flavors and no FDA approval and no regulation until just recently, it’s difficult to track voluntary recalls or product modifications among manufacturers in the e-cig market.

One of the largest manufacturers of e-liquids voluntarily recalled 5,000 bottles of Groovy Grape flavoring after finding it could potentially cause popcorn lung.

Explosive Product – More Product Recalls

Some brands of e-cigarettes have been known to overheat and possibly explode, resulting in burns (mostly in the mouth) and other severe injuries for e-cig users. The malfunction is likely due to the use of lithium-ion batteries to power the e-cigarettes. One teenage boy was so badly injured following an explosion of an e-cigarette that he spent five days in the hospital and suffered permanent injuries, including blindness. People who suffered injuries from explosions and fires have filed e-cigarette lawsuits.

E-cigarette explosions, although just making their way into the media more often more recently, are nothing too new. Incidents of e-cigarette explosions have been reported to the US Fire Administration dating back to 2009, just two years following the release of e-cigs into the US market.

Other data reported in 2014 included the following:
  • More than 2.5 million Americans are using e-cigarettes, and this number is rapidly growing

  • 25 incidents of explosions and fires involving e-cigarettes were reported between 2009 and August 2014

  • 9 injuries were associated with those incidents, with 2 of the injuries involving serious burns when the product exploded in the users’ mouths

  • Most incidents (20) occurred while the battery was charging

  • 84% of those incidents resulted in moderate or minor fire spread, including the ignition of nearby objects such as carpets, drapes, bedding, couches and/or vehicle seats

  • The shape and construction of e-cigarettes can make them more likely than other products containing lithium-ion batteries to act as “flaming rockets” as a result of battery failures

One manufacturer, Cloupor, issued a voluntary recall of its product after finding that it had the potential to overheat and/or short circuit. But in a statement issued by the company in 2015, the China-based high-tech manufacturer assured its users that although the defect may cause the circuit board to melt, “it will never reach [an] ignition point to make other things burn, let alone catch fire.”

FDA Recommendations

Although e-cigarettes are still not considered a FDA-approved product, the FDA recently offered some recommendations to help users of e-cigarettes avoid potential battery malfunctions and/or explosions and resulting injuries, such as burns.

1 . Consider using vapes with safety features

such as firing button locks, vent holes and protection against overcharging

2. Keep your vape covered

don’t let it come into contact with coins or loose batteries in your pocket

3. Never charge your vape with a phone or tablet charger

always use the charger that came with it

4. Don’t charge your vape overnight

or leave it charging unattended

5. Replace the batteries if they get damaged or wet

if your vape gets damaged and the batteries are not replaceable, contact the manufacturer

e-cigarette charger
To avoid malfunction, the FDA recommends only charging a vape with it's specific charger

E-Cigarette Use Among Youth

Up until 2016, there were no age restrictions on the sale and use of e-cigarettes. And the fact that over 7,000 kid-friendly flavors exist, including bubble gum and fruity mixtures, has several government agencies concerned about their appeal to youth. The Centers for Disease Control (CDC) announced in 2012 that e-cigarette use among adolescents (middle and high schoolers) had doubled between 2011 and 2012. The CDC also voiced its concern that vaping may be a gateway for teens to eventually use tobacco.

The National Institute on Drug Abuse published the following data regarding teens and e-cigarettes in 2016:
  • Teens are more likely to use e-cigarettes than traditional cigarettes

  • The monthly percentage of e-cigarette use among teens steadily increases with age; results from the data showed a range from 9.5% in 8th grade to 16.2% in 12th grade

  • Twice as many boys use e-cigarettes as girls

  • Teens who use e-cigarettes are more likely to start smoking; results showed 30.7% of e-cig users would start smoking within 6 months compared to 8.1% of non-e-cig smokers

  • 66% of teens say that “just flavoring” is in their e-cigarette, 7% don’t know, 13.2% say nicotine and 5.8% say marijuana

  • 7 in 10 teens have been exposed to e-cigarette advertising

New FDA Regulation

In May 2016, the FDA announced that it finalized a rule extending its oversight to all tobacco products, including e-cigarettes. The FDA stated in its news release that e-cigarette use among high schoolers increased from 1.5 percent in 2011 to 16 percent in 2015.

Did You Know
E-cigarette use among high school aged teens increased from 1.5 percent in 2011 to 16 percent in 2015.

It further found that in 2015, 3 million middle and high school students were using e-cigarettes; and a joint study by the FDA and the National Institutes of Health showed that in 2013 to 2014, about 80 percent of youth tobacco users reported using a flavored tobacco in the past 30 days, with the availability of flavors being the primary reason for use.

The new FDA regulations restricted the sale of e-cigarettes to individuals 18 and over, both online and in-person, and made showing a photo ID a requirement for age verification. It also limited the sale of tobacco products in vending machines to only be allowed in adult-only facilities and restricted the distribution of free samples.

Beginning in 2018, all newly-regulated tobacco products, including e-cigarettes, must display the following warning statement on product packages and advertisements:

“WARNING: This product contains nicotine. Nicotine is an addictive chemical.”

If the manufacturer submits a self-certification statement to the FDA that the product does not contain nicotine, and has data to support its claim, then the alternate label must read:

“This product is made from tobacco.”

Please seek the advice of a medical professional before making health care decisions.

Related Pages
Kristin Compton
Written By Kristin Compton Writer

Kristin Compton's background is in legal studies. She worked as a paralegal before joining Drugwatch as a writer and researcher. She was also a member of the National Association of Legal Assistants. A mother and longtime patient, she has firsthand experience of the harmful effects prescription drugs can have on women and their children. Some of her qualifications include:

  • Bachelor of Arts in Legal Studies | Pre-Law from University of West Florida
  • Past employment with The Health Law Firm and Kerrigan, Estess, Rankin, McLeod & Thompson LLC
  • Personal experience battling severe food allergies, asthma and high-risk pregnancies
Edited By
Kevin Connolly
Kevin Connolly Managing Editor
Medically Reviewed By
Dr. John A. Daller
Dr. John A. Daller American Board of Surgery

22 Cited Research Articles

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