Vaping is completely harmless

What we know

E-cigarettes work by heating a liquid, typically containing nicotine, flavorings, propylene glycol, and vegetable glycerin, into an aerosol that the user inhales. Marketing for these products, along with a widespread public impression built up over the past decade, has often framed vaping as a clean or harmless alternative to smoking, sometimes using the term "vapor" to suggest the aerosol is comparable to steam. Laboratory analysis has repeatedly found that this aerosol is not simply flavored water vapor: it contains ultrafine particles capable of penetrating deep into lung tissue, along with measurable concentrations of heavy metals such as nickel, tin, and lead, and volatile organic compounds, some of which are known carcinogens.

Nicotine itself, present in the large majority of vaping products on the market, is a highly addictive substance that raises heart rate and blood pressure and has documented adverse effects on adolescent brain development, since the brain's prefrontal cortex, responsible for impulse control and decision-making, continues developing until roughly the mid-twenties. The U.S. Surgeon General and the CDC have both identified youth e-cigarette use as a significant public health concern, since it has become disproportionately common among teenagers, in part due to flavored products and discreet device designs, and has been associated with subsequently higher rates of combustible cigarette initiation among young people who might not otherwise have started smoking.

In 2019, a distinct and severe respiratory illness termed EVALI (e-cigarette or vaping product use-associated lung injury) emerged in the United States, ultimately causing over 2,800 hospitalizations and at least 68 confirmed deaths according to CDC tracking. Investigation traced the majority of these cases to vitamin E acetate, a thickening agent found in illicit THC-containing vaping products rather than in regulated nicotine e-cigarettes, but the outbreak drew national attention to the broader reality that vaping aerosols can cause acute, severe lung injury under certain conditions, undermining the "harmless vapor" framing regardless of the specific causative agent involved.

Beyond this acute outbreak, longer-term research has documented other physiological effects. Several studies have found that vaping is associated with increased arterial stiffness and endothelial dysfunction, changes in blood vessel function that are established risk markers for future cardiovascular disease, occurring within a shorter timeframe of use than researchers initially expected. Other studies have found evidence of impaired lung function and increased airway inflammation among regular vapers compared to non-users, and some research suggests immune cell changes in the lungs.

The comparative claim that vaping is less harmful than combustible cigarette smoking, which has been made by public health bodies including Public Health England and, with more caveats, the U.S. FDA, is a genuinely different claim from vaping being safe in absolute terms, and this distinction is frequently lost or conflated in public discussion. Combustion, the actual burning of tobacco, produces thousands of chemicals, including tar and carbon monoxide, that are largely absent from vaping aerosol, which is why switching completely from cigarettes to vaping is generally considered a harm-reduction step for adult smokers who are otherwise unable to quit nicotine entirely. But this relative comparison applies specifically to adult smokers substituting one product for another, not to nonsmokers, and certainly not to adolescents, for whom vaping represents a new and avoidable health risk and nicotine exposure rather than a reduction of an existing one. The World Health Organization continues to caution that vaping products are not proven safe and are not recommended as a smoking cessation aid outside of specific regulated frameworks in some countries.

Common claims

• Vaping is completely harmless.Not supported
• Vaping is safer than smoking cigarettes.Partly supported, for adult smokers switching completely
• E-cigarette aerosol is just harmless water vapor.Not supported
• EVALI lung injuries were caused by regulated nicotine vapes.Not supported, mainly linked to illicit THC products

Evidence hierarchy

All sources

• Outbreak of lung injury associated with e-cigarette use, or vapingCDC · 2023
• E-cigarette use among youthU.S. Surgeon General / HHS · 2018
• Vaping and cardiovascular healthJournal of the American Heart Association · 2021
• Evidence review of e-cigarettes and heated tobacco productsPublic Health England / UK Government · 2022
• Vaping devices (e-cigarettes)National Institute on Drug Abuse (NIDA) · 2023

Related terms