Vaping, the act of vaporizing a liquid to inhale, is an increasingly popular alternative to cigarette smoking. However, it could damage health by irritating the lungs and throat and introducing toxins into the body.

Some vape product manufacturers claim that vaping is a completely safe alternative to smoking. However, early research into the safety of the practice suggests this is not the case. In fact, it appears that vaping, even without nicotine, can have harmful effects on the body.

This article discusses the current research on the side effects of vaping without nicotine.

What is e-liquid?

E-liquid refers to the liquid that vape devices or electronic cigarettes vaporize. People may also call it e-juice or vape juice. The side effects that a person experiences when vaping depend partly on the type of e-liquid they use.

The specific components of e-liquids vary among brands and products. The base liquid is generally a blend of ingredients such as water, vegetable glycerine, and propylene glycol. Manufacturers then add different flavorings or additives to this mixture to create a particular flavor.

Many of these ingredients have a Generally Recognized as Safe (GRAS)Trusted Source certification - a Food and Drug Administration (FDA) designation - for use in food products. However, the vaping process heats and vaporizes these ingredients, and there is little research that suggests food-grade ingredients are safe for vaping.

Additionally, the Centers for Disease Control and Prevention (CDC)Trusted Source state that vape aerosol can contain dangerous substances aside from nicotine, including:

diacetyl, which has links to lung disease

heavy metals such as nickel, tin, and lead

other volatile organic compounds

Effects

Vaping without nicotine prevents nicotine dependence and other side effects that have an association with nicotine.

However, vaping without nicotine can also cause side effects, including those below.

General toxicity

Many of the chemicals in e-liquids may have toxic effects on the body. A 2012 laboratory study found that these effects were due not to nicotine but to the chemicals that manufacturers use to flavor e-liquids. Importantly, this was also the case for e-liquids that consisted of food-grade ingredients.

A 2015 study showed that heating the propylene glycol and glycerol in e-liquids creates compounds that release formaldehyde. According to the International Agency for Research, formaldehyde is a Group 1 carcinogen, meaning that it has the potential to cause cancer. A more recent study investigated the effects of e-liquid on young vape users.

The study compared three groups of adolescents:

those who used e-cigarettes only

those who used e-cigarettes in addition to smoking standard cigarettes

and those who had never used either

Overall, the study showed that vaping was less damaging than cigarette smoking. However, adolescents in the e-cigarettes only group had significantly higher quantities of toxic chemicals in their urine compared with those in the control group. These chemicals included:

acrylonitrile

acrolein

propylene oxide

acrylamide

crotonaldehyde

Other research supports these findings, showing that heating and vaporizing e-liquid chemicals makes them especially toxic to lung cells. As a result, the researchers “caution against the widely held opinion that e-cigarettes are safe.”

Additionally, some vape manufacturers add vitamin E acetate to vaping liquids containing tetrahydrocannabinol - a cannabinoid commonly known as THC - to thicken or dilute them. According to a 2019 studyTrusted Source, vitamin E acetate is a sticky substance that has associations with lung injury.

Lung and throat irritation

In the short term, vaping e-liquid can irritate the lungs and throat. People who vape often refer to this as a “throat hit.” This term describes the tingling, burning sensation that a person experiences as they inhale the vapor.

This sensation comes from heating and inhaling the chemicals in the e-liquid. As the authors of a 2015 studyTrusted Source note, inhaling large amounts of propylene glycol and glycerol can irritate the airways. They also point out that the levels of these chemicals in the e-cigarette are high enough to cause irritation after just one puff.

Inflammation

A 2018 study found several common e-liquid flavoring ingredients caused a damaging inflammatory response in lung cell samples. The e-liquids that the study examined did not contain nicotine.

Chronic inflammation of lung tissue can lead to irreversible lung scarring.

Larger scale studies in humans will help establish the long-term risks that e-liquid vapors pose to lung tissue. However, early evidence suggests they negatively affect these organs.