What the evidence says about vaping as a way to quit smoking

Many adults who smoke wonder whether switching to a vape is a sensible way to stop, and the major health bodies do not all answer in the same tone. The most thorough single source is the Cochrane review of electronic cigarettes for smoking cessation, a "living" review that pools trial results and is updated as new studies appear. Its 2025 update reports that nicotine e-cigarettes, in absolute terms, might translate to an additional four quitters per 100 compared with nicotine replacement therapy, and it rates the direction of that result as high-certainty evidence. This page covers what the review measured, where the FDA, CDC, NHS and WHO agree and differ, and what is still unknown. It is not advice to start vaping, and people who do not smoke should not start.

What the Cochrane review measured

The 2025 update, led by Nicola Lindson, included 90 completed studies with 29,044 participants, of which 49 were randomized controlled trials. Searches ran to 1 February 2024. The main outcome was whether a person had stopped smoking for at least six months.

Against nicotine replacement therapy (patches, gum and similar products), people using nicotine e-cigarettes were more likely to stop smoking. The risk ratio was 1.59 (95% confidence interval 1.30 to 1.93) across 7 studies and 2,544 participants. A risk ratio above 1 means more quitters in the e-cigarette group. The plain-language summary puts it simply: of every 100 people using nicotine e-cigarettes to stop smoking, 8 to 10 might succeed, compared with 6 of 100 using nicotine replacement therapy, 7 of 100 using e-cigarettes without nicotine, and 4 of 100 given no support or behavioural support only.

How certain are those results?

For nicotine versus non-nicotine e-cigarettes the risk ratio was 1.46 (6 studies, 1,613 participants), rated moderate-certainty. For nicotine e-cigarettes versus behavioural support only or no support, the risk ratio was 1.96 (11 studies, 6,819 participants), but the authors rate it low-certainty because of risk of bias in how those studies were run. The main limit, the authors say, is few trials with low event rates.

On side effects, the picture is incomplete. The most commonly reported problems were throat or mouth irritation, headache, cough and nausea, which tended to ease with continued use. Serious adverse events were rare, and the review says there is insufficient evidence to tell whether rates differ between groups. The authors did not detect evidence of serious harm from nicotine e-cigarettes, but say longer, larger studies are needed to evaluate safety fully. The trials tested regulated, nicotine-containing products; illicit products or those containing substances such as THC may carry different risks. Participants were adults who smoked, so the findings do not speak to young people or to anyone who does not already smoke.

What FDA, CDC, NHS and WHO say

The FDA states that e-cigarettes can generally be a lower-risk alternative for adults who smoke cigarettes, but that their use is not risk-free, because they deliver harmful chemicals and contain nicotine, which is highly addictive. It adds that people who do not use tobacco products should not start. The CDC says e-cigarettes may have the potential to benefit adults who smoke and are not pregnant if used as a complete substitute for smoked tobacco, but no e-cigarette has been approved by the FDA as a smoking cessation aid and more research is needed.

The NHS is more openly positive. It says nicotine vaping is less harmful than smoking and one of the most effective tools for quitting, and that you are roughly twice as likely to quit with a nicotine vape as with other nicotine replacement products. It also says vaping is not completely harmless, long-term effects are not yet known, and children and non-smokers should never vape. Its healthiest option is to neither smoke nor vape, so people who vape to quit should aim to stop eventually.

The World Health Organization is the most cautious. Its question-and-answer page says e-cigarettes as consumer products have not been proven effective for cessation at the population level, that they are harmful and not safe, and that it is too early for a clear answer on long-term effects. Where countries do pursue e-cigarettes for cessation, WHO recommends regulating them as medicines. The four positions differ in emphasis, and all four say people who do not smoke should not take up vaping.

Long-term effects and nicotine itself

E-cigarette aerosol generally contains fewer toxic chemicals than cigarette smoke, according to the CDC, which adds that it is not harmless and that long-term effects remain uncertain. The NHS says vaping has not been around long enough to know the risks of long-term use. Nicotine is a separate concern: WHO calls it highly addictive and harmful, particularly for children and adolescents whose brains are still developing. Someone who swaps cigarettes for a vape may stay dependent, which is why how nicotine dependence works matters for the later step of stopping vaping.

Dual use: vaping and smoking together

The CDC warns that using both e-cigarettes and regular cigarettes is not an effective way to safeguard health, and that smoking even a few cigarettes a day can be dangerous. The FDA says long periods of dual use can cause harms similar to, or in addition to, those from smoking alone. WHO states that dual use, which is common, is at least as dangerous as smoking or vaping alone and likely more so.

Youth use

The CDC reports that in 2024, 5.9% of US middle and high school students (1.63 million) currently used e-cigarettes, the most commonly used tobacco product among them. It notes that nicotine can harm the parts of an adolescent's brain that control attention, learning, mood and impulse control. WHO states that high-quality studies consistently show e-cigarette use increases later cigarette uptake among non-smoking youth by nearly 3 times.

Where vaping fits among other options

The CDC notes that the FDA has approved seven medications to help people quit smoking, and that combining medication with counselling raises the chance further. Those routes are covered on the pages for nicotine replacement therapy, prescription medicines for quitting and counselling and quitlines, and the overall comparison is on quit methods compared.

Anyone who is pregnant, has heart disease or a mental health condition, takes other medicines, or is thinking about using a vape to quit can ask a doctor, pharmacist or stop smoking adviser which approach fits their situation. The CDC says e-cigarettes should not be used by women who are pregnant. Severe symptoms of any kind are a reason to seek medical care promptly.

The short version

For adults who already smoke, the Cochrane review found that nicotine e-cigarettes helped more people stop than nicotine replacement therapy, with high-certainty evidence for that comparison and less certain evidence on safety over the long term. The agencies agree that dual use is a poor outcome and that people who do not smoke should not start. A doctor, pharmacist or stop smoking adviser can help weigh the options, particularly during pregnancy or with heart disease, a mental health condition or other medicines.