Vaping is the act of inhaling an aerosol produced by an electronic device that heats a liquid into a fine mist. Unlike traditional cigarettes, which burn tobacco to create smoke, vaping devices use an electrically heated coil to vaporize a liquid solution, delivering nicotine (or sometimes just flavor) without combustion. The result looks like smoke but is technically an aerosol, a mix of tiny liquid droplets and gas that carries nicotine and other chemicals into the lungs.
How a Vaping Device Works
Every vaping device has the same basic components: a battery, a small heating coil, a wick that absorbs liquid, and a reservoir that holds the e-liquid. When you take a puff (or press a button, depending on the device), the battery sends electrical current through the coil. The coil heats up rapidly, vaporizing the liquid soaked into the wick. That vapor cools almost instantly into an aerosol you inhale.
The liquid itself is simple in concept. At minimum, it contains propylene glycol, vegetable glycerin, nicotine, and flavoring. Propylene glycol is a thin, colorless liquid that produces the “throat hit” many users associate with smoking. Vegetable glycerin is thicker and sweeter, responsible for the dense visible clouds. Most e-liquids blend the two in varying ratios, and the balance between them changes the feel of each puff. Higher propylene glycol means a sharper sensation in the throat; higher vegetable glycerin means smoother flavor and bigger clouds.
Types of Vaping Devices
Vaping hardware has changed significantly since the first devices appeared on the market. The earliest models, called cigalikes, looked like traditional cigarettes and were designed to feel familiar to smokers. They were simple and disposable but had short battery life and delivered nicotine poorly.
Vape pens came next, with longer battery life and better flavor from improved tank and coil designs. Third-generation devices, often called box mods, gave users control over wattage and temperature settings, letting them fine-tune vapor production. These devices use coils with very low electrical resistance to produce large clouds of vapor.
The most popular devices today are pod systems. They’re small, lightweight, and use pre-filled or refillable cartridges called pods. Pod systems are what most people picture when they think of modern vaping. They typically use a specific form of nicotine called nicotine salt, which behaves differently in the body than the freebase nicotine found in older devices and traditional cigarettes.
How Nicotine Salts Changed Vaping
Nicotine in e-liquid comes in two forms: freebase nicotine and nicotine salts. The difference matters because it affects how quickly nicotine reaches the brain and how the experience feels. Nicotine salts reach their peak concentration in the blood faster than freebase nicotine. In animal studies, nicotine salts hit peak blood levels more rapidly, and test animals self-administered significantly more of the salt form, suggesting it may be more reinforcing.
This faster delivery is part of why pod-based devices became so widely used, particularly among younger people. A small, discreet device using nicotine salts can deliver a satisfying hit of nicotine without the harshness of high-concentration freebase liquid. Many popular pods contain 50 milligrams of nicotine per milliliter, a concentration that would be unpleasantly harsh in freebase form.
What Vaping Does to the Body
Vaping is not the same as breathing water vapor. The aerosol contains chemicals that affect the cardiovascular and respiratory systems in measurable ways, even after short-term use.
On the heart and blood vessels, nicotine-containing e-cigarettes increase arterial stiffness, a marker of cardiovascular stress. This stiffening has been observed within minutes of use and persists for at least 20 minutes afterward. Heart rate increases are comparable to those caused by traditional cigarettes, both immediately after use and up to two hours later. Studies in mice found that after eight months of e-cigarette exposure, arterial stiffness was similar to that of mice exposed to cigarette smoke. Perhaps more concerning, even a single vaping session has been shown to reduce the ability of blood vessels to dilate properly, a sign of damage to the cells lining the arteries.
In the lungs, the base liquids themselves (not just the nicotine) trigger changes. Exposure to propylene glycol and vegetable glycerin aerosol increases production of a mucus protein that, at elevated levels, is a marker for chronic obstructive pulmonary disease. The aerosol also raises levels of inflammatory signals and an enzyme that breaks down lung tissue. E-cigarette users show elevated levels of the same destructive enzyme found in traditional smokers, compared to people who have never smoked.
How Vaping Compares to Smoking
Combustion is what makes cigarettes so deadly. Burning tobacco at temperatures above 600°C generates thousands of chemicals, dozens of which are known carcinogens. Vaping avoids combustion entirely. The aerosol from e-cigarettes does not contain appreciable amounts of tobacco-specific nitrosamines, which are among the most harmful cancer-causing compounds in cigarette smoke. Other toxic byproducts of burning, called pyrolysis products, are also absent.
This is why public health agencies generally describe vaping as less harmful than smoking, not as safe. The cardiovascular and lung effects described above show that “less harmful” still means real biological consequences. For someone who has never smoked, picking up a vaping habit introduces risks that didn’t exist before. For a current smoker who fully switches, the reduction in exposure to combustion chemicals is significant.
The EVALI Outbreak
In 2019, a wave of severe lung injuries swept across the United States, eventually named EVALI (e-cigarette or vaping product use-associated lung injury). The CDC identified vitamin E acetate as the cause. This oily compound was used as a thickening agent in black-market THC vaping cartridges, and it was found both in the products themselves and in fluid taken from patients’ lungs.
Vitamin E acetate is not a standard ingredient in commercially sold nicotine e-liquids. The outbreak was tied specifically to illicit THC products, though it raised broader awareness of the risks of inhaling unregulated substances. The CDC’s guidance is straightforward: vitamin E acetate should never be added to any vaping product, and users should not add any substance not intended by the manufacturer.
Regulation in the United States
The FDA regulates e-cigarettes as tobacco products. Any company that wants to sell a vaping product legally in the U.S. must submit a premarket tobacco product application and receive authorization. As of early 2026, only 41 e-cigarette products have been authorized by the FDA. These are the only ones that may be lawfully sold in the country.
The gap between that number and the thousands of products available in convenience stores and online is enormous. Many flavored disposable vapes on the market have never received FDA authorization, and enforcement against unauthorized products has been an ongoing challenge. This means that many of the devices people actually use have not been reviewed for their impact on public health.
Environmental Cost of Disposable Vapes
Disposable vapes are a growing waste problem. Each device is a small piece of electronic equipment containing a lithium-ion battery, a circuit board, plastic casing, and metal components, all designed to be thrown away after a single use. The median weight of a disposable vape is about 50 grams, with plastic making up as much as 80% of the device or metal (including the battery) accounting for up to 85%.
The chemical complexity inside these devices makes safe disposal difficult. Analysis of disposable vapes has found arsenic, lead, mercury, and other toxic metals in various components. The batteries contain cobalt, copper, iron, and nickel, along with trace amounts of gold, lead, and mercury. When these devices end up in landfills or littered on streets, those metals can leach into soil and water. The mix of materials also makes recycling extremely challenging, since separating plastics, metals, circuit boards, and battery components from a device the size of a highlighter pen is not economically practical at scale.