What the evidence shows about vaping and lung cancer
Vaping has not yet caused the documented lung cancer cases that cigarette smoking has, but the evidence that it is safe is not there either. Vaping exposes your lungs to chemicals that are known to damage cells—nicotine, propylene glycol, vegetable glycerin, and flavoring compounds—but lung cancer typically takes years or decades to develop. Because vaping became widespread only in the last 15 years, we do not yet have the long-term data to say whether it will cause cancer at the rates smoking does.
What we do know is that vaping damages lung tissue in ways that could increase cancer risk. Studies show that vaping inflames the airways, reduces the lung's ability to clear mucus and dead cells, and causes changes in the cells that line the lungs. These changes are similar to the early stages of damage that precedes cancer, but they are not cancer itself. The question is whether years of this damage will lead to cancer in people who vape regularly.
Key Takeaways
- Vaping has not yet caused documented lung cancer cases in the way smoking has, but long-term data does not exist because vaping is too recent.
- Vaping exposes your lungs to chemicals that damage the cells lining your airways, which is a known step toward cancer development.
- Some vaping liquids and heating methods produce formaldehyde and other carcinogens, though usually at lower levels than cigarette smoke.
- The cancer risk from vaping is lower than from smoking, but it is not zero, and the full picture will not be clear for another decade or more.
How vaping damages lung cells
When you inhale vapor, it does not simply pass through your lungs unchanged. The chemicals in vape liquid—especially propylene glycol and vegetable glycerin—irritate the lining of your airways. This irritation triggers inflammation, which is your body's attempt to repair the damage. Repeated inflammation over months or years can change how cells behave and make them more likely to become abnormal.
Nicotine itself does not directly cause cancer, but it can weaken your immune system's ability to detect and destroy abnormal cells. Some of the flavorings used in vape liquids, particularly diacetyl (which causes a condition called popcorn lung) and cinnamaldehyde, have been shown to damage airway cells in laboratory studies. When vape liquid is heated to high temperatures, it can also break down into formaldehyde and acetaldehyde—both known carcinogens—though the amounts are typically lower than in cigarette smoke.
What research has found so far
Animal studies show that long-term exposure to vaping chemicals can cause changes in lung tissue that resemble early cancer development. Mice exposed to nicotine and propylene glycol vapor for extended periods developed inflammation and cellular changes that increased their susceptibility to other cancer-causing agents. However, animal studies do not always predict what happens in humans, and mice lungs are not identical to human lungs.
Human studies are limited because vaping has not been around long enough for researchers to follow large groups of people for 20 or 30 years. The longest studies so far have tracked vapers for about 3 to 5 years and have not found lung cancer cases. But this absence of cases does not mean vaping is safe—it means we have not waited long enough to know. Researchers are now looking at whether vapers show the same early warning signs (like precancerous cell changes) that smokers do, and some studies suggest they may.
Comparing vaping to cigarette smoking
Cigarette smoke contains over 7,000 chemicals, at least 70 of which are known to cause cancer. Vape aerosol contains far fewer chemicals overall, and the levels of known carcinogens are generally lower than in cigarette smoke. This is why public health organizations consider vaping less harmful than smoking. However, "less harmful" does not mean "harmless."
A person who switches from smoking to vaping almost certainly reduces their cancer risk compared to continuing to smoke. But a person who has never smoked and starts vaping is taking on a cancer risk they would not otherwise have. The difference matters for how you should think about your own situation.
Who is at higher risk
People who vape heavily—multiple times per day, every day—are exposed to more of these chemicals than occasional users. The longer someone vapes, the more cumulative damage their lungs experience. People who heat their vape liquid to very high temperatures may produce more formaldehyde and other breakdown products. Those who use vape products with added vitamin E acetate (which was common in some cannabis vaping products) may face additional lung injury risk.
People with existing lung disease, a family history of lung cancer, or who are current or former smokers may be at higher risk if they also vape. If you have any of these risk factors and are considering vaping, talking with a doctor about your specific situation is worthwhile.
What happens in your lungs over time
The first changes from vaping happen quickly—within days or weeks, inflammation appears in the airways. Over months, the cells lining your lungs may begin to show abnormal growth patterns. Over years, repeated cycles of damage and attempted repair can lead to scarring and further cellular changes. This progression is similar to what happens in smokers, but the timeline and severity are unknown because we have not observed it long enough.
Some people who vape develop bronchitis-like symptoms—cough, phlegm, shortness of breath—which suggests their lungs are being irritated. Others have no symptoms at all, even though cellular damage may be occurring. The absence of symptoms does not mean the lungs are unharmed.
What you should know about vaping and your health
If you currently smoke, switching to vaping reduces your cancer risk compared to continuing to smoke, though it does not eliminate it. If you have never smoked and are considering vaping, the evidence suggests you would be better off not starting, because you would be introducing a cancer risk where none existed before.
If you already vape and are concerned about your health, reducing how often you vape or stopping altogether will lower your exposure to these chemicals. There is no safe level of vaping that has been proven, so any reduction in use reduces risk. If you develop a persistent cough, chest pain, or shortness of breath, these warrant a conversation with a doctor, regardless of whether you vape.
Frequently Asked Questions
Has anyone gotten lung cancer from vaping?
No confirmed cases of lung cancer caused solely by vaping have been documented yet. However, vaping has not been around long enough for cancer to develop in most users—lung cancer typically takes 20 to 30 years to appear after exposure to carcinogens. The absence of cases now does not mean cases will not appear in the future.
Is vaping safer than smoking for lung cancer risk?
Yes, vaping carries a lower cancer risk than smoking because it exposes your lungs to fewer carcinogens and at lower levels. However, lower risk is not the same as no risk. If you do not smoke and do not vape, your cancer risk is lower than if you do either one.
Can you get lung cancer from secondhand vape?
Secondhand vape exposure is much lighter than secondhand smoke, and no cases of lung cancer from secondhand vape have been documented. However, secondhand vape does expose bystanders to nicotine and other chemicals, so it is not completely harmless, especially with repeated exposure.
What should I do if I vape and want to reduce my cancer risk?
The most effective step is to stop vaping entirely. If you are not ready to stop, reducing how often you vape and avoiding very high temperatures will lower your chemical exposure. If you vape because you are trying to quit smoking, talk with a doctor about other options like nicotine patches or prescription medications that may help.
Does the type of vape liquid matter for cancer risk?
Yes. Liquids with fewer additives and flavorings carry lower risk than those with many flavoring chemicals. Vaping at lower temperatures produces fewer carcinogenic breakdown products than high-temperature vaping. Cannabis vaping products that contained vitamin E acetate were linked to serious lung injury, so avoiding those is important.