Some e-cigarette ingredients shown to be more toxic than others, study says

Jeremy Wong smokes an e-cigarette at The Vaping Buddha on January 23, 2018 in South San Francisco, California. (Photo by Justin Sullivan/Getty Images)
Jeremy Wong smokes an e-cigarette at The Vaping Buddha on January 23, 2018 in South San Francisco, California. (Photo by Justin Sullivan/Getty Images) (Getty Images)

ROANOKE, Va – There's less information published on the effects of smoking e-cigarettes than there is on the effects of smoking regular cigarettes, but a new study is looking to increase the information surrounding the effects of e-cigs.

Researchers with the UNC School of Medicine found that smoking e-cigarettes, also known as vaping, reduces cells' ability to properly function.

As most of the liquid used in these devices contains nicotine, an addictive substance found in tobacco leaves, e-cigarettes are sonsidered to be tobacco products.

According to the Center for Tobacco Regulatory Science and Lung Health, e-liquids are composed of propylene glycol, or PG; vegetable glycerin, or VG; flavorings; and other chemical additives, such as the aforementioned nicotine.


While those ingredients are the building blocks of e-liquids, not all e-liquids are the same.

"We found that e-liquid ingredients are extremely diverse, and some of them are more toxic than nicotine alone and more toxic than just the standard base ingredients in e-cigarettes - propylene glycol and vegetable glycerin," said study senior author Robert Tarran, Ph.D., an associate professor of cell biology and physiology.

The scientists studied these liquids, compared them and developed a system to evaluate their toxicity, using large plastic plates with hundreds of indentations in them, in which fast-growing human cells were exposed. 

They discovered that the greater the toxicity, the more harmful its effects were on human cells and their growth rate. 

Propylene glycol and vegetable glycerin are base products considered to be nontoxic except when they're inhaled. As such, the scientists found that even small doses of these liquids, whether combined with nicotine or not, significantly reduced the growth of the test cells. 

The addition of ingredients to these two substances makes the liquid even more toxic, and the greatest toxicity comes from two flavor compounds: vanillin and cinnamaldehyde.

"The higher the concentrations of these compounds in particular, the more toxic the e-liquids were," said Dr. Flori Sassano, research project manager in Tarran lab. "There are more than 7,700 e-liquid products out there (sold under names like "Cotton Candy," "Strawberry Milk," and "Berry Splash"), and regulators as well as ordinary people should know more about the ingredients they contain and how toxic they might be."

As the number of vapers continues to rise, it's important to understand the terminology that comes with vaping.


Below is a list of terms to know in relation to e-cigarettes, from Science News for Students:

e-cigarette: Short for electronic cigarette, it's a battery-powered device that disperses nicotine and other chemicals as tiny airborne particles that users can inhale. These devices heat up a flavored liquid until it evaporates, producing vapors. People who use these devices are known as vapers.

e-liquid: The term applies to the solutions heated to the evaporation point in an electronic cigarette. These solutions are the basis of the vapors that will be inhaled. The liquid typically contains a solvent into which flavorings and nicotine have been dissolved.

nicotine: It's a colorless, oily chemical produced in tobacco and certain other plants. It creates the “buzz” associated with smoking. Highly addictive, nicotine is the substance that makes it hard for smokers to give up their use of cigarettes. The chemical is also a poison, that is sometimes used as a pesticide to kill insects and even some invasive snakes or frogs.

pollutant: It's a substance that taints something, such as the air, water, our bodies or products.

tobacco: It's a plant cultivated for its leaves, which many people burn in cigars, cigarettes and pipes. Tobacco leaves also are sometimes chewed. The main active drug in tobacco leaves is nicotine, a powerful stimulant and poison.

vaping: It's a slang term for the use of e-cigarettes because these devices emit vapor, not smoke. People who do this are referred to as vapers and they vape

vapors: These are the fumes released when a liquid transforms to a gas, usually as a result of heating.