E-cigarettes are often marketed as a safer alternative to cigarettes, and because of this, they have gained widespread popularity, particularly among teens and young adults. This is untrue however, as these devices contain many harmful ingredients that can negatively affect health. Unfortunately, many people are unaware of the chemical makeup of e-cigarettes, assuming they only contain water vapor and nicotine. Experts explain that e-cigarettes can contain heavy metals, volatile organic compounds (VOCs), chemicals that create flavorings, and ultrafine particles that significantly and negatively affect your health. “E-cigarettes are addictive and dangerous due to the presence of nicotine, a highly addictive substance, and other harmful chemicals in the vapor,” Dr. Albert Rizzo, Chief Medical Officer of the American Lung Association explained. He spoke with us more about some of the harmful chemicals to look out for.
1. Nicotine
Nicotine is a highly addictive substance found in most tobacco products and is usually delivered in higher concentrations in e-cigarettes. Once inhaled, nicotine is quickly absorbed into the blood stream and begins to affect the brain. “Nicotine in e-cigarettes can quickly reach the brain, impact its reward system and lead to dependence,” said Dr. Rizzo. “Nicotine triggers the release of dopamine, a neurotransmitter associated with pleasure and reward, in the brain's reward center, making users crave more. This dopamine surge creates a cycle of dependence, where individuals continue using e-cigarettes to experience the pleasurable effects and avoid withdrawal symptoms.”
This is particularly harmful for adolescents whose brains are still developing. Early exposure to nicotine can affect a child’s attention control, learning, mood and impulse control. Long term, this can lead to cognitive deficits, increased susceptibility to addiction, anxiety, depression and impaired academic performance.
Nicotine also stimulates the adrenal glands, which increases blood pressure and heart rate and can, over time, lead to cardiovascular disease, leading to a number of health issues. Additionally, nicotine can rewire the brain, enhancing the reward and addiction pathways, which makes quitting extremely difficult.
2. Propylene Glycol and Vegetable Glycerin
These are the primary carriers of nicotine and flavorings in e-liquids. Though they are common additives in food and believed to be safe for ingestion, they are also used to make things like antifreeze, paint solvents and artificial smoke in fog machines which are dangerous when inhaled. When heated, propylene glycol and vegetable glycerin break down into formaldehyde and acetaldehyde—both carcinogens. Inhaling these chemicals over time may cause inflammation of the airways and damage to lung tissue, which in turn can lead to chronic respiratory diseases.
3. Flavoring Chemicals
Chemicals used to create flavorings may create buttery or creamy tastes, but they can be extremely hazardous. While less present in e-cigarettes currently on the market, the chemical acetoin can break down into diacetyl, which has been linked to a condition called bronchiolitis obliterans, or "popcorn lung" due to it being first discovered amongst workers in microwave popcorn factories. This serious and irreversible disease damages the smallest airways in the lungs, leading to coughing, wheezing and shortness of breath. Acetyl propionyl, also known as 2,3-pentanedione, often used as a substitute for diacetyl, has similar health risks. Even flavors considered mild or fruity may contain toxic compounds that produce free radicals and oxidative stress, contributing to cell damage and inflammation. Unfortunately, these appealing flavors in e-cigarettes can mask the harshness of the chemicals, making it easier for young users to start and continue using them.
4. Heavy Metals
The heating coils in e-cigarettes are typically made of metal alloys like nickel, chromium and lead. These metal particles can find their way into the aerosol and accumulate in the body if inhaled. Inhalation of these metals can damage organs over time. For example, lead is a neurotoxin and has been linked to developmental delays in children and increased risk of neurological disorders in adults. Chronic exposure to heavy metals can also impair kidney function and elevate cancer risk.
5. Volatile Organic Compounds (VOCs)
E-cigarette aerosols may also contain VOCs such as benzene, toluene and xylene. These are the same toxic chemicals found in gasoline and paint thinner. VOCs are known to irritate the eyes, nose and throat, and long-term exposure can damage the liver, kidneys and central nervous system. Some VOCs are also classified as carcinogens, with repeated exposure increasing the likelihood of developing certain cancers. “The composition of e-cigarettes is not as regulated as traditional cigarettes. There are a variety of harmful substances beyond just nicotine, including carcinogens like formaldehyde and acrolein, heavy metals like lead, and ultrafine particles that can damage the lungs contained in e-cigarettes and the amounts vary from product to product,” said Dr. Rizzo.
Although e-cigarettes are often marketed as a safer alternative to smoking, the reality is they introduce a host of harmful chemicals into the body. “E-cigarettes, or vapes, are not a safe alternative to traditional cigarettes despite common perceptions,” Dr. Rizzo explained. “E-cigarettes have not been studied as long or as effectively as traditional cigarettes because e-cigarettes come in many different styles with no regulation of contents. But we know that E-cigarettes are linked to lung injuries, heart disease, and can perpetuate nicotine addiction.”
From nicotine and heavy metals to carcinogenic compounds and volatile organic chemicals, each ingredient poses unique threats to health. The risks are even more pronounced for children and teens, whose bodies and brains are still developing. Raising awareness about these dangers is crucial to preventing long-term health consequences and curbing the rising public health crisis of youth vaping.
Blog last updated: July 11, 2025
