The safety and long-term health effects of using e-cigarettes or other vaping products still aren’t well known. In September 2019, federal and state health authorities began investigating an outbreak of a severe lung disease associated with e-cigarettes and other vaping products. We’re closely monitoring the situation and will update our content as soon as more information is available.

Recent research has led to some misleading headlines, some of which claim that vaping can cause cancer.

This isn’t true. There isn’t any evidence that suggests vaping causes cancer.

However, there is some evidence that suggests vaping may increase your overall risk for cancer. This is different than directly causing cancer.

We break down the tentative connection, assess the effects of different e-fluids, and more.

There are no documented cancer diagnoses directly linked to vaping or e-cigarette use. However, this remains a difficult question to answer for a few reasons.

Not only is vaping a relatively recent phenomenon, people who vape tend to be on the younger side.

According to one 2018 study, most people who use e-cigarettes are under the age of 35.

It can take decades before long-term effects appear. For example, most lung cancer diagnoses occur after the age of 65.

As a result, it could be years before we understand the link between vaping and long-term effects, such as cancer.

Another issue is that most people who vape are also current or former cigarette smokers.

The same 2018 study reported only 15 percent of people who vape have never smoked cigarettes.

This presents a challenge for researchers, as it’s difficult to determine which health effects are caused by vaping, cigarette use, or a combination of the two.

It depends. If you use vaping as way to avoid or quit smoking cigarettes, vaping actually decreases your overall cancer risk.

But if you’ve never smoked cigarettes and aren’t planning on starting, vaping increases your overall cancer risk.

Although a 2018 review suggests vaping poses fewer health risks than smoking cigarettes, vaping isn’t risk-free.

And given the current lack of long-term studies, the overall health effects of vaping aren’t well-understood.

More research is needed to understand the potential implications of long-term vaping.

Vaping has been linked to an increased risk of the following cancers:

This isn’t an exhaustive list, though. Additional research could link vaping to other types of cancer.

Most studies have focused on lung cancer. In one 2017 animal study, researchers found that exposure to e-cigarette vapor led to DNA- and gene-level changes that could increase the risk of lung cancer.

Another animal study from 2018 concluded that smoke from e-cigarettes might contribute to lung and bladder cancer in humans.

These animal studies have significant limitations. In particular, they can’t replicate the way people actually use vaping devices. More research is needed.

Nicotine is what makes tobacco products addictive. Some vape juices contain nicotine while others do not.

The relationship between nicotine and cancer is a complex one. In general, research suggests nicotine exposure does present a cancer risk.

The results from a 2018 animal study suggest nicotine from e-cigarette vapor:

  • damages DNA
  • limits DNA repair
  • enhances cell mutation

However, one major limitation of this study is that the animals were exposed to a dose much higher than that of typical vape use in humans.

More data is needed to understand the long-term effects of vaping with nicotine.

Juice flavor might have an impact on cancer risk.

One 2018 study on teens who vape found that fruit-based flavors contained higher levels of acrylonitrile, a toxic chemical.

The U.S. Environmental Protection Agency (EPA) classifies acrylonitrile as a “probable human carcinogen.”

In general, different flavors do appear to pose different health risks.

For example, one 2018 study examined the effects of common vape juice-flavoring chemicals on monocytes, a type of white blood cell.

Researchers found cinnamaldehyde (cinnamon flavor) was the most toxic to white blood cells. O-vanillin (vanilla flavor) and pentanedione (honey flavor) also had significant toxic cellular effects.

One 2016 study found that certain vape juice flavors were more toxic to lung cells. Among the flavors tested, strawberry was the most toxic. Coffee- and menthol-flavored e-juices also had toxic effects.

A study from 2017 also found that some common vape juice-flavoring chemicals, particularly diacetyl (butter/popcorn flavor), have been associated with severe respiratory illnesses.

Vaping devices and liquids are regulated by the U.S. Food and Drug Administration (FDA). Labeling requirements include a warning if the product contains nicotine.

Manufacturers aren’t required to list e-juice ingredients. However, as of 2018, they are required to submit an ingredient list to the FDA.

Juices and e-liquids contain several different types of ingredients. The main ingredients are listed below.


Different vape juices contain different nicotine concentrations.

Higher nicotine concentrations are associated with an increased risk of adverse health effects.

People who are dependent on nicotine may consider gradually tapering the quantity of nicotine per milliliter.

Base liquids

The base is a flavorless suspension that constitutes most of the liquid in vape juice. Most manufacturers use a combination of propylene glycol (PG) or vegetable glycerin (VG), which is also referred to as glycerin or glycerol.

Both of these substances are classified as generally recognized as safe (GRAS) by the FDA. They appear in food, cosmetic, and pharmaceutical products.

However, this doesn’t mean adverse side effects aren’t possible.

One 2015 study used gas chromatography to assess the risks associated with exposure to PG and VG in a shisha pen. Researchers found the concentrations were high enough to potentially irritate the airways.


These ingredients vary according to the flavor of the juice. Some flavoring chemicals appear to be more toxic than others, while others can react with base liquids to create new and potentially toxic chemical compounds.

Research into both the short- and long-term health effects of flavoring ingredients is ongoing. More research is needed to fully understand which ingredients to avoid.

The following list includes flavoring chemicals that have been identified as potentially harmful:

  • acetoin
  • acetyl propionyl
  • acrolein
  • acrylamide
  • acrylonitrile
  • benzaldehyde
  • cinnamaldehyde
  • citral
  • crotonaldehyde
  • diacetyl
  • ethylvanillin
  • formaldehyde
  • o-vanillin
  • pentanedione (2,3-pentanedione)
  • propylene oxide
  • vanillin

It might not be possible to know the ingredients in a particular e-juice.

If you’re unable to review a product’s ingredient list, you might find it helpful to avoid the flavors that have been associated with the chemicals listed above.

These flavors include:

  • butter/popcorn
  • cherry
  • cinnamon
  • coffee
  • custard
  • fruity
  • menthol
  • strawberry
  • vanilla

“Juuling” is a term that comes from a popular e-cigarette brand, Juul. It’s essentially the same as vaping. The risks described in this article also apply to juuling.

Smoking cigarettes and vaping affect the lungs differently. More research is necessary to truly understand their unique effects, though.

Cigarettes contain chemicals that irritate and damage tissue in your airways and lungs.

The tar in cigarette smoke can also build up in the lungs. This makes it more difficult to breathe.

Over time, smoking cigarettes can increase your risk for lung diseases, such as:

E-cigarettes contain fewer toxic chemicals than cigarettes. They don’t emit tar.

However, e-cigarettes still contain chemicals that could affect the lungs. More research is necessary to identify the long-term effects of extended exposure.

There are currently no cases linking vaping to popcorn lung.

Popcorn lung refers to a rare but serious lung condition called bronchiolitis obliterans, or fixed obstructive lung disease.

This condition inflames the lungs’ smallest airways (bronchioles), making it difficult to breathe.

The reference to popcorn comes from a chemical called diacetyl, which is used as a flavoring ingredient in microwave popcorn.

Diacetyl also appears in some vaping e-liquids.

Research has linked inhaling diacetyl at microwave popcorn manufacturing plants with certain lung diseases.

More research needs to be done to understand the short- and long-term effects of inhaling diacetyl in e-juice.

The risks associated with vaping vary according to the device, e-juice, and habits of the user.

Some potential short-term risks include:

  • coughing
  • increased heart rate
  • decreased oxygen saturation in the lungs
  • increased airway resistance
  • decreased air volume in the lungs

Some potential long-term risks include:

  • nicotine addiction
  • exposure to toxic chemicals
  • increased likelihood of smoking cigarettes

There’s currently no evidence that vaping increases the risk of heart or lung disease.

Research suggesting that vaping e-liquids contain high levels of heavy metals is limited.

Vaping may also present unique risks to teenagers and young adults.

There’s still a lot we don’t know about vaping. On the whole, though, it appears to present fewer risks than smoking cigarettes.

Based on what we know, vaping poses less of a cancer risk than smoking cigarettes. However, it might present an increased risk for people who don’t currently smoke cigarettes.

Speak to a doctor or other healthcare professional if you’re trying to quit smoking or have questions about vaping.