What Ingredients Are in Juul Pods and Other Vaping Products?

In This Article

10/21/2019 UPDATE: Recent illnesses have been associated with use of e-cigarettes (vaping). Since the specific causes of these lung injury cases are not yet known, the Centers for Disease Control and Prevention (CDC) recommends refraining from all vaping products.

While vaping has been touted by some to be a less harmful alternative to smoking, the aerosol created by electronic cigarette devices is far from a harmless vapor. The aerosol put out by Juul and other e-cigarette devices can contain potentially harmful substances like nicotine, metals, and toxins. Here’s what we know about the different ingredients found vaping products and how they might impact your health. 

As of Dec. 20, 2019, the new legal age minimum is 21 years old for purchasing cigarettes, cigars, or any other tobacco products in the United States.


The bulk of vaping fluid is made up of solvents. These clear liquids serve as the base for the fluid and make vapor when they’re heated up—thus the name “vaping.” The two most common solvents used in vaping products are propylene glycol and glycerin, with some products (like Juul) containing a combination of the two. 

  • Propylene Glycol: An odorless, tasteless fluid that absorbs water from other things. It’s used in a lot of different ways, including in cosmetics, food products, and medicines to manage moisture or absorb excess water.
  • Glycerin: Also known as vegetable glycerin or glycerol, glycerin is a fluid used in a range of industries. Like propylene glycol, glycerin is odorless with a syrupy consistency; however, it differs slightly in that it has a mild, sweet flavor to it. 

While both of these solvents are considered to be safe by the U.S. Food and Drug Administration when ingested, what isn’t well known is how safe they are when heated up and inhaled.

Vaping devices like Juul work by using hot coils to heat up liquids to create a vapor. But the temperature of the coils can cause the solvents to break down and form new chemicals.  

For example, when propylene glycol is heated by the coils in an electronic cigarette, it can form acetol (hydroxyacetone) and 2-propen-1-ol (allyl alcohol), while glycerin can form glycidol and acrolein. Both of the solvents, however, can degrade and form formaldehyde, which can be toxic in high doses.


Traditionally, vaping manufacturers like Juul have added flavors to their products to make them taste better to users. Flavorings are often used in food products to manufacture or enhance flavors, but the safety of these products can change when they’re inhaled as opposed to being eaten or touched.  

Two examples of flavoring ingredients added to e-cigarettes are diacetyl and benzaldehyde. 

  • Diacetyl: Diacetyl is a chemical sometimes added to vaping products to create rich flavors like butterscotch or caramel. Food manufacturers use this flavoring chemical in a wide range of capacities—perhaps most (in)famously in microwave popcorn. Diacetyl smells and tastes like butter. But while diacetyl is generally considered safe by the FDA when eaten, it can potentially wreak havoc in the lungs when it’s inhaled, leading to a condition known as “popcorn lung."
  • Benzaldehyde: This is a flavoring that smells a little like almonds and is found in a broad range of products, including perfumes, medications, and e-cigarettes. Much of the research done on the safety of benzaldehyde has focused on ingestion, but there’s some evidence that breathing in large amounts of the chemical can irritate the respiratory tract and cause shortness of breath. 

The U.S. Food and Drug Administration now bans the manufacture and sale of flavored vaping products (excluding menthol and tobacco). The new policy is effective as of Feb. 1, 2020. 

Risk of Flavorings for Young People

The tasty flavors often added to vape products are a big part of their appeal, especially for young people. Kid-friendly flavors like cotton candy or fruit punch have been particularly popular among teens, who cite flavorings as the most common ingredient in the vaping products they use.

Added flavors can also make e-fluids a poisoning risk for small children who mistake the fluid for candy or fruit juice. Poison control centers get thousands of calls every year in the U.S. due to exposure to e-cigarette devices and liquid nicotine, according to the National Poison Data System of the American Association of Poison Control Centers. For small children, in particular, coming into contact with liquid nicotine—even through the skin—could lead to nausea, vomiting, and death.

Because of these risks, the FDA made moves in the summer of 2019 to ban unauthorized flavors in electronic cigarettes. The response among e-cigarette manufacturers was mixed. Juul, for example, announced it would stop the sale of non-menthol or tobacco-flavored products in traditional retail stores but continues to sell other flavored products on its website. These policies, however, are still being fine-tuned, and some counterfeit or homemade products might continue to contain unapproved flavorings.


Vaping devices are also popular delivery mechanisms for mind-altering chemicals and additives, especially nicotine and THC. 


Many vaping products contain nicotine, the highly addictive substance found in traditional tobacco products. Nicotine affects the reward centers in the brain, making it hard to quit using nicotine once you start. The more you use nicotine, the more your brain starts to rely on it to get the same effect and the harder it is to stop. 

But addiction isn’t the only risk associated with nicotine. It’s also been linked to a range of other health issues, including:

  • Cancer
  • Cardiovascular diseases and heart attacks.
  • Suppressed immune system
  • Premature labor, miscarriage, and other reproductive health issues 
  • Impaired cognitive functions like learning, concentration, or memory   

Nicotine in Juul and Other E-Cigarettes

The amount of nicotine in e-cigarettes varies a lot from one product to the next. For example, Juul pods—the liquid cartridges used by Juul devices—have two different levels of nicotine: 40 milligrams (mg) labeled as 5% strength and 23 mg labeled as 3% strength. A 5% strength pod has about the same amount of nicotine as a pack of cigarettes and roughly double that of many other e-cigarette brands.

The high levels of nicotine in Juul products might come as a surprise to a lot of its users. When surveyed, nearly two-thirds (63%) had no idea Juul pods contain nicotine. 

Not all vaping manufacturers report how much nicotine is in their products, but even when they do, analyses show what’s inside the vape juice doesn’t always match what is said on the packaging. One study, for example, detected measurable amounts of nicotine in some vaping products despite labels claiming the product to be nicotine-free.

Nicotine Salts vs Freebase Nicotine

It’s not just the presence of nicotine that matters. The type of nicotine used in e-cigarette products can also affect how quickly the chemical is absorbed into the body, as well as how much a person is able to take in. 

Juul, for example, uses a nicotine salt formulation—that is, nicotine extracted from natural tobacco leaves. It packs nearly the same punch of nicotine as from smoking, but (when combined with benzoic acid, another ingredient in Juul pods) it goes down a lot smoother. It doesn’t cause the same throat or chest irritation that happens with combustible cigarettes, allowing people to inhale more deeply or more frequently, potentially exposing them to even more nicotine. 

Most other vaping brands use a chemically altered form of nicotine known as freebase nicotine. Freebase nicotine is technically more potent than naturally-occurring tobacco nicotine salts, but they tend to bother the throat and chest. As a result, formulated nicotine salts used by manufacturers like Juul are effectively stronger than freebase because they can use a higher concentration of nicotine without being harsh.

Nicotine in Young People

While traditional tobacco use among middle and high school students has remained pretty stagnant in recent years, e-cigarette use is climbing. The estimated number of high school students using e-cigarettes like Juul jumped from 11.7% to 20.8% from 2017 to 2018.

Nicotine is particularly dangerous for teens and young adults because their brains aren't yet fully developed. As a result, developing an addiction to nicotine during adolescence could make them more likely to smoke or develop other substance use disorders (ex. with alcohol or cocaine) later in life.

E-Cigarettes Are Not Nicotine Replacement Therapy

When they first came out, some e-cig proponents touted the devices as a less-harmful nicotine delivery system than cigarettes and even promoted them as an alternative to nicotine replacement therapy medications like skin patches or chewing gum. 

While research is mixed at best on whether vaping devices actually help people quit smoking, e-cigarettes have yet to be approved by the FDA as a form of nicotine replacement therapy or smoking cessation. 


As marijuana use has become legalized and decriminalized in many parts of the U.S., e-cigarette products have started to include options to vape cannabis-derived substances like tetrahydrocannabinol (THC).

THC is a psychoactive chemical found in marijuana (the dried leaves and stems of the cannabis plant). It’s what makes people feel “high” when using marijuana, and it can have some profound effects on the body.

Some health effects of THC include: 

  • Impaired body movement
  • Issues thinking or problem-solving
  • Loss of mental capacity, such as with memory or learning
  • Hallucinations or delusions (with high doses) 

In the summer of 2019, cases of serious lung issues tied to vaping began cropping up throughout the U.S. Many (though not all) of the people who got sick used vaping products that contained THC. As a precaution, health officials warned people to refrain from using electronic cigarettes, especially those containing THC.


In some cases, ingredients in vaping devices weren’t put there on purpose. They’re a byproduct of the manufacturing process or debris from the devices themselves. Some of the contaminants found in e-cigarettes include ultrafine particulates and metals—both of which can be damaging to the lungs.

Ultrafine Particles 

Human lungs aren’t designed to handle foreign debris, which is part of why smoking is so harmful. When you inhale smoke from a cigarette, tiny pieces of burned, treated tobacco get into the delicate tissue of the lungs, sparking inflammation and opening the door for toxic chemicals to enter the bloodstream.

Vaping doesn’t burn tobacco leaves; it heats up fluids to create an aerosol. That vapor doesn’t contain a lot of the debris found in cigarettes, but it can still contain ultrafine particles that can irritate the sensitive tissue deep in the lungs. 


The tiny coils used in vaping devices to heat up liquids are often made of metal. Over time, tiny pieces of metal can make their way into the aerosol and, eventually, the delicate tissue of the lungs. 

Some of the metals found in e-cig vapor include:

  • Aluminum, a metal that, when inhaled, can damage the lungs and lead to asthma or pulmonary fibrosis. 
  • Chromium, a carcinogen linked to lung cancer when inhaled. 
  • Copper, which can irritate the lungs and cause coughing, pain, or runny nose. 
  • Iron, which can irritate the nose, throat, and lungs and lead to coughing, wheezing, or shortness of breath. 
  • Lead, a highly toxic metal that can damage the brain and kidneys, regardless of whether it’s inhaled or ingested. 
  • Magnesium, which, when inhaled, can irritate the lungs and make it hard to breathe. 
  • Nickel, a carcinogen that can lead to lung cancer when inhaled, as well as chronic bronchitis, emphysema, and pulmonary fibrosis. 
  • Tin, which can lead to pneumoconiosis (a lung disease caused by mineral dusts) or inflammation in the lungs. 
  • Titanium, which can irritate the lungs and lead to shortness of breath and bronchitis.  

The types and concentrations of these metals vary widely from one product to the next; however, research shows the presence of these metals in e-cigarette aerosol is often far above what is considered to be safe, especially when inhaled.  

One 2013 study, for example, found that the aerosol put out by e-cigarettes had just as much lead as some traditional cigarettes and even higher concentrations of other metals nickel and iron.

Secondhand Vaping

The harmful substances found in some e-cig aerosol might not just affect those who vape. Just like cigarettes could put others at risk of inhaling secondhand smoke, there is some evidence to suggest secondhand vaping could increase the chances of a non-user being exposed to some ingredients found in e-cigarettes, particularly nicotine. 

A Word from Verywell 

Vaping products aren’t always clearly labeled, and some ingredients lists can be misleading or incomplete, especially considering the chemical changes that can take place at different temperatures used by e-cigarettes. Likewise, people sometimes use bootleg or home-brewed vaping products that might contain other harmful substances not yet known. As a result, it’s difficult to know what’s in any one product, and a lot more research is needed into how these ingredients might affect a person’s health long-term.

That said, there’s enough evidence to show that the health risks of vaping could be substantial, especially for kids and young adults.

If you or someone you know is addicted to vaping, talk to your doctor right away about how to quit.

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Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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