Vaping can irritate and harm the lungs, but the long-term risk is still unknown. The clearest proven lung harm is EVALI, a 2019 outbreak tied mostly to THC vapes from informal sources.

Vaping is not for non-smokers, pregnant people, or anyone under 21, the US minimum sales age. For adults who smoke, switching completely is expected to be less harmful than smoking, but it is not risk-free.

Vaping means inhaling an aerosol made when an e-cigarette heats a liquid. That liquid usually contains nicotine, flavorings, and other chemicals.

In the 2025 National Youth Tobacco Survey, 5.2% of US middle and high school students (about 1.44 million) reported current e-cigarette use, according to the FDA's summary of NYTS results.

What is Vaping?

An e-cigarette has a battery, a heating coil, and a tank, pod, or cartridge of e-liquid (also called vape juice). The battery heats the coil, which turns the liquid into an aerosol that you inhale.

Chinese pharmacist Hon Lik is credited with inventing the first modern e-cigarette in the early 2000s. Devices now range from small disposables and pods to larger refillable mods.

Aerosol from an e-cigarette generally has fewer harmful chemicals than cigarette smoke. The CDC stresses that "this does not make e-cigarettes safe."

Potential Health Risks of Vaping

The CDC lists what vape aerosol can contain: nicotine, cancer-causing chemicals, heavy metals such as nickel, tin, and lead, volatile organic compounds, tiny particles that reach deep into the lungs, and flavorings such as diacetyl.

Diacetyl is a buttery flavoring linked to bronchiolitis obliterans ("popcorn lung") in factory workers who breathed it at work. The NHS says vaping does not cause popcorn lung, and the UK bans diacetyl in regulated nicotine e-liquids.

Chemicals such as formaldehyde and acrolein can form when e-liquid is heated. They can irritate airways and damage cells, though levels are generally much lower than in cigarette smoke.

Nicotine itself is highly addictive. It can also harm the developing brain, which keeps maturing until about age 25.

The long-term effects of vaping on lung disease, cancer, and heart disease are still unknown, because people have not vaped long enough for those studies to finish.

Internal Link: Is Vaping Bad for You

Study Findings on Vaping and Lung Damage

The most thorough review is the 2018 report from the National Academies of Sciences, Engineering, and Medicine. It graded each finding by how strong the evidence was.

Conclusive evidence: most e-cigarettes emit numerous potentially toxic substances besides nicotine.
Moderate evidence: teens who vape have more cough and wheeze, and vaping is linked to more asthma flare-ups.
Limited evidence: lab and animal studies show harm to the respiratory system.
No available evidence (as of 2018): whether e-cigarettes cause respiratory diseases in humans.

The same report found conclusive evidence that adults who switch completely from cigarettes cut their exposure to many toxicants and carcinogens found in smoke.

Using both vapes and cigarettes ("dual use") doesn't give you that benefit, and the CDC warns it may worsen respiratory health.

Chemicals in Vaping Products

Most e-liquids contain propylene glycol (PG), vegetable glycerin (VG), flavorings, and nicotine.

PG and VG make the visible vapor and carry the nicotine and flavor. Both are considered safe in food, but less is known about inhaling them heated, day after day.

Nicotine is highly addictive. Nicotine-free liquids exist, but most vapes sold contain nicotine.

Flavorings are safe to eat but not necessarily safe to inhale. Diacetyl and similar buttery flavorings are the best-known concern.

E-cigarette aerosol also contains metals, which can come from the heating coil and other device parts. The amounts depend on the device and how it is used.

Because devices, liquids, and power settings vary so much, two vapers can be exposed to very different amounts of the same chemicals.

Continue reading: Case Studies and Real-Life Examples

Case Studies and Real-Life Examples

The best-documented case of vaping-related lung damage is the 2019–2020 outbreak of EVALI (e-cigarette, or vaping, product use-associated lung injury).

By February 18, 2020, the CDC had counted 2,807 hospitalized cases and 68 deaths. Lab tests strongly linked the outbreak to vitamin E acetate, an additive found in some THC vaping products.

Most patients had used THC products from informal sources such as friends, family, or dealers. The CDC still advises against using THC vapes from informal sources and against adding anything to a vape that the maker didn't intend.

Outside of EVALI, doctors have published individual case reports of lung problems in people who vape. Single cases can't prove that vaping caused the illness, which is why larger studies matter.

If you vape and develop shortness of breath, chest pain, or a cough that won't go away, see a doctor and tell them what products you use.

Regulations and Warnings

In the US, the FDA has regulated e-cigarettes as tobacco products since 2016. A company needs a written FDA marketing order before it can legally sell a new vaping product.

FDA says an authorization does not mean a product is safe or FDA approved. Since December 20, 2019, federal law has made it illegal to sell any tobacco product, including e-cigarettes, to anyone under 21.

The European Union regulates e-cigarettes under its Tobacco Products Directive, which sets rules for safety, labeling, and nicotine strength.

Health agencies agree on two points. Non-smokers and young people should never start vaping, and the long-term effects are still being studied.

Tips for Quitting Vaping

If you want to quit vaping, the approach is much like quitting smoking, because both involve nicotine addiction.

Suggestions for individuals looking to quit vaping

Set a quit date: Pick a specific day so you have a clear target.
Identify triggers: Note the situations, moods, or places that make you reach for your vape, and plan how to handle them.
Seek support: Tell friends and family, and ask for their help.
Replace the habit: Exercise, deep breathing, or a hobby can help you ride out cravings.
Step down nicotine: Lowering nicotine strength gradually can ease withdrawal for some people.
Talk to a health care provider: Ask about FDA-approved quit medications, which can help with cravings.
Practice self-care: Get enough sleep and eat regular meals while your body adjusts.

Resources and support available

1-800-QUIT-NOW: Free, confidential coaching from trained quit coaches.
Smokefree.gov: Free online tools and the SmokefreeTXT text program, run by the National Cancer Institute.
Centers for Disease Control and Prevention (CDC): The CDC's vaping and quitting page explains how counseling plus medication gives adults the best chance of quitting for good.

Conclusion

Vaping exposes the lungs to nicotine, metals, fine particles, and chemicals that can cause irritation and cell damage. It is not safe, and the long-term risks are still unknown.

The proven, serious lung injuries so far came mostly from THC vapes containing vitamin E acetate. That's why the source of what you vape matters.

For adults who smoke, switching completely to vaping reduces exposure to many toxicants in smoke. For everyone else, the safest choice is not to start.

Related Articles:

Sources

Public Health Consequences of E-Cigarettes: Conclusions by Level of Evidence, National Academies of Sciences, Engineering, and Medicine
Outbreak of Lung Injury Associated with the Use of E-Cigarette, or Vaping, Products, Centers for Disease Control and Prevention
Health Effects of Vaping, Centers for Disease Control and Prevention
Vaping myths and the facts, NHS Better Health