Vaping vs Smoking: Which Is Actually Worse?

Q: Does switching from smoking to vaping reduce health risk?

Yes, if you switch completely. In the Annals study, people using only e-cigarettes had much lower carcinogen and toxin levels than smokers. The key word is "completely".

Many people are making health decisions based on whether they believe vaping is meaningfully different from smoking. Some overestimate how safe vaping is. Others dismiss it as equally bad. Both are wrong. Here's a dimension-by-dimension comparison, with each claim linked to its source.

The short answer: if you smoke, switching completely to vaping exposes you to far fewer toxicants, and the evidence that vaping is much less harmful is strong even though the famous 95% figure is not. Using both leaves your toxicant levels close to a smoker's. If you do not smoke, vaping only adds risk, and its long-term effects are still unknown.

Chemical Exposure

Cigarette Smoke

Burning tobacco produces more than 7,000 chemicals, at least 250 known to be harmful and at least 69 that can cause cancer, according to the National Cancer Institute — tar, carbon monoxide, benzene, formaldehyde, hydrogen cyanide, arsenic, cadmium and tobacco-specific nitrosamines among them. See the cigarette chemicals list.

Vape Aerosol

A vape heats a liquid rather than burning tobacco. The NHS says most of the harmful chemicals in tobacco smoke, including tar and carbon monoxide, are not contained in vape aerosol. The aerosol still contains nicotine, propylene glycol, glycerine, flavourings and some toxic substances. A lab study of 12 e-cigarette brands found toxicant levels in the vapour 9 to 450 times lower than in cigarette smoke. For more, see is vaping bad for you.

In people: a 2017 study in Annals of Internal Medicine compared long-term users and found that people using only e-cigarettes had substantially lower levels of carcinogen and toxin biomarkers than smokers — but people who both smoked and vaped had levels similar to smokers. The UK's 2022 evidence review reached the same conclusion across many studies: significantly lower exposure in vapers than smokers to toxicants linked to cancer, respiratory and cardiovascular disease.

Cancer Risk

Cigarettes: the causal link is among the best established in medicine. The CDC says smoking and secondhand smoke cause almost 9 of every 10 lung cancer deaths, and that tobacco can cause cancer almost anywhere in the body.

Vaping: the biggest unanswered question. Exposure to carcinogens is far lower than from smoking, as above. But cancer develops over decades, and the NHS says vaping has not been around for long enough to know the risks of long-term use. The reasonable reading: cancer risk is very likely much lower than from smoking, but not zero, and nobody can yet put a number on it.

Cardiovascular Impact

Cigarettes: smoking damages blood vessels, raises clotting and inflammation, and adds carbon monoxide to the blood. Heart disease and stroke account for about 39% of the premature deaths smoking causes in the US.

Vaping: nicotine raises heart rate and blood pressure and narrows blood vessels whichever way it is taken, so vaping is not heart-neutral. But vapes produce no carbon monoxide, and a randomised trial found that smokers who switched to e-cigarettes had measurably better blood-vessel function within one month — with no difference between nicotine and nicotine-free e-cigarettes over that time.

Respiratory Effects

Cigarettes: cause COPD, emphysema and chronic bronchitis, and are the dominant cause of lung cancer.

Vaping: the NHS lists coughing, a dry mouth and throat, irritation and shortness of breath among common side effects. Whether decades of vaping cause COPD is unknown: the UK's 2022 review could not summarise vaping exposure beyond 12 months. See what vaping does to your lungs.

Nicotine Delivery and Addiction

This is the one area where vaping is not clearly better.

The UK's 2022 review found that in the medium to long term, and especially in experienced vapers, nicotine exposure from vaping was comparable to smoking. Vapes also have no natural stopping point — a cigarette burns down; a vape doesn't — so use can spread across the whole day. See how much nicotine is in a vape. The product is far less toxic, but the addiction can be just as strong. The vape puffs to cigarettes calculator puts your own puffs a day on the same scale as cigarettes.

The "95% Less Harmful" Claim

In 2015, Public Health England published an evidence review saying that the current best estimate is that e-cigarettes are around 95% less harmful than smoking. The figure is widely quoted, and deserves context.

Where it came from: an earlier expert-panel exercise in which a group scored 12 nicotine products on 14 harm criteria; cigarettes scored 100 and everything but small cigars and pipes scored 15 or less.

The criticism: it was expert judgement, not a measurement, and The Lancet questioned the figure and some panel members' conflicts of interest in a 2015 editorial. A precise percentage suggests more certainty than exists.

The balanced view: the direction — much less harmful than smoking — is well supported, and the 2022 UK review still concludes that in the short and medium term, vaping poses a small fraction of the risks of smoking. The exact figure is a rough estimate.

The "Lesser Evil" Framing

For a smoker, switching completely to vaping is a clear health improvement. For someone who has never smoked, starting to vape adds nicotine addiction and risks that weren't there — the NHS says children and non-smokers should never vape.

The public health challenge is saying both things at once: vaping is much less harmful than smoking, and vaping is not harmless.

FAQ

Is vaping worse than smoking?

No. Vaping exposes you to far fewer and lower levels of toxicants, and switchers show better blood-vessel function within a month. But nicotine exposure and addiction can be comparable to smoking, and long-term risks are unknown.

Is vaping 95% safer than smoking?

That figure is Public Health England's 2015 "best estimate", based on expert judgement rather than measurement. The direction — much less harmful — is well supported; the exact number isn't.

Does switching from smoking to vaping reduce health risk?

Yes, if you switch completely. In the Annals study, people using only e-cigarettes had much lower carcinogen and toxin levels than smokers. The key word is "completely".

Is dual use safer than smoking alone?

Not by much, on the evidence so far. In the same study, people who both smoked and vaped had carcinogen and toxin levels largely similar to people who only smoked.

Why do some countries promote vaping while others ban it?

Different regulators weigh the evidence differently. The UK encourages smokers to switch; Australia restricts vaping over concerns about young people's use. These reflect real uncertainty and different judgements about population and individual risk.

What if I quit both?

That's the best outcome. The NHS says the healthiest option is not to smoke or vape, and that if you vape to quit smoking you should aim to eventually stop vaping too.