Is Vaping Bad for You? What the Research Actually Shows

The honest answer is more nuanced than either side usually admits. The NHS puts it in three sentences: nicotine vaping is less harmful than smoking; vaping is not completely harmless; and we don't know yet what the long-term effects may be. The UK's 2022 evidence review adds that in the short and medium term, vaping poses a small fraction of the risks of smoking — and that it could not summarise vaping exposure beyond 12 months.

What's in Vape Aerosol

The visible cloud is usually called "vapour", but it's an aerosol — fine liquid droplets plus gases. What's in it:

Base Liquids

Propylene glycol (PG) and glycerine (VG) are approved for use in food, which is a different thing from inhaling them every day for years. The NHS lists mouth and throat irritation, a dry mouth and throat, and coughing among vaping's common side effects.

Nicotine

Nicotine is addictive, and it raises heart rate and blood pressure and narrows blood vessels whichever way it's taken. The NHS says children and non-smokers should never vape, partly because young people's brains are still developing.

Flavourings

Thousands of flavouring chemicals are used, and most were tested for eating, not inhaling. Specific concerns:

Diacetyl and related butter-flavour chemicals: linked to a serious lung disease in factory workers. A Harvard study found diacetyl in 39 of 51 flavoured e-cigarette products tested. See popcorn lung for what that does and doesn't mean for vapers.
Cinnamaldehyde (cinnamon): in a lab study, 20 of 39 refill fluids contained it at levels toxic to human lung cells.
Pulegone (mint): classified by the International Agency for Research on Cancer as possibly carcinogenic to humans (Group 2B).

Heating By-Products

Heating the liquid creates new compounds — formaldehyde, acetaldehyde and acrolein among them, more at higher power — and small amounts of metals from the coil. A lab study found toxicant levels in e-cigarette vapour 9 to 450 times lower than in cigarette smoke.

Respiratory Effects

Symptoms: the NHS lists coughing and shortness of breath among common vaping side effects. In large population data the picture is less clear-cut than often claimed: in the US PATH study, exclusive e-cigarette use was largely not linked to wheezing or night-time cough once past smoking was accounted for, while any cigarette smoking was.

Immune cells: in a lab study, e-cigarette vapour condensate killed human lung macrophages and impaired their ability to engulf bacteria; nicotine-free condensate was less toxic but still had effects. The authors note that research in people is still needed.

The unknown: diseases like COPD and lung cancer take decades to develop. We don't yet know whether decades of vaping cause them at meaningful rates. See what vaping does to your lungs and vaping side effects.

Cardiovascular Effects

Nicotine raises heart rate and blood pressure and narrows blood vessels whichever way it's taken. Beyond nicotine:

Short-term blood-vessel changes: in a 2019 study of 31 healthy non-smokers, a single session of nicotine-free vaping temporarily impaired blood-vessel function
For smokers who switch, the direction reverses: a randomised trial found blood-vessel function improved within a month of switching from cigarettes to e-cigarettes

Whether vaping's short-term effects lead to heart disease over decades isn't known. See nicotine's effect on the heart.

Oral Health

A dry mouth is a common vaping side effect, and a dry mouth is bad for teeth and gums. Good long-term studies of vaping and gum disease are still lacking.

The Harm Reduction Context

For people who would otherwise smoke, switching completely to vaping almost certainly reduces health risk a great deal: the UK review found significantly lower exposure to toxicants linked to cancer, respiratory and heart disease in vapers than in smokers. Our vaping vs smoking comparison goes dimension by dimension.

But the harm-reduction case applies only to the vaping-versus-smoking comparison. For a never-smoker, starting to vape adds risks that weren't there. For a smoker, switching reduces but doesn't remove risk — and the NHS advises aiming to stop vaping too, eventually.

FAQ

Is vaping bad for your lungs?

To some degree, probably. The NHS lists coughing, throat irritation and shortness of breath among common side effects, and lab studies show vapour can harm lung immune cells. It is far less harmful than smoking, and the long-term risk isn't yet known.

Is vaping safe without nicotine?

Safer, not safe. Nicotine-free aerosol still contains PG, glycerine, flavourings and heating by-products, and one study found a single session of nicotine-free vaping temporarily impaired blood-vessel function in healthy non-smokers.

How does vaping compare to smoking?

Vaping exposes you to far fewer toxic chemicals at much lower levels. It is much less harmful than smoking — which is a low bar.

What about secondhand vape exposure?

Exhaled aerosol contains nicotine and fine particles, at lower levels than secondhand cigarette smoke. It's still sensible not to vape around children or in enclosed spaces with others.

Should I switch from smoking to vaping?

If you smoke and haven't been able to stop another way, the NHS says vaping is one of the most effective tools for quitting smoking and much less harmful than smoking — aim to stop vaping eventually too. If you don't smoke, there's no health reason to start.

Are some vapes safer than others?

Lower nicotine means less dependence, and lower power produces fewer heating by-products. Avoiding flavours known to contain diacetyl or cinnamaldehyde may reduce respiratory risk. Buy from reputable retailers — in the UK, products covered by UK safety regulations. No vape is completely safe.