E-cigarettes loaded with nicotine can help people quit smoking, a new evidence review has concluded.

Nicotine vapes produce quit rates 20% to 40% higher than traditional nicotine replacement therapies like patches or gum, researchers recently reported in the journal Addiction.

“We set out to determine if scientists agree on whether nicotine e-cigarettes help people quit smoking,” said senior researcher Jamie Hartmann-Boyce, an assistant professor of health policy and management at the University of Massachusetts Amherst.

“Based on the consistency of the findings here, it’s clear that they do,” she said in a news release.

For the new study, researchers analyzed data pooled from 14 previous reviews covering 109 studies conducted between 2014 and 2023.

Every pooled estimate pointed in the same direction, researchers said – smokers using nicotine e-cigarettes were more likely to quit than those using most other methods.

The effectiveness of e-cigarettes might stem from the way they’re used, as well as the nicotine they deliver, Hartmann-Boyce said.

“If you look at neuro-imaging studies, the addiction often isn’t just to the nicotine,” she said. “There are the sensory cues around it that really feed into those addiction pathways. Vaping fulfills some of those cues in a way that a patch doesn’t.”

For example, smokers receive a throat hit from puffing on a vape like that from a tobacco cigarette, perform the same hand-to-mouth motion to take a drag and have a visible exhale similar to smoking, researchers said.

However, nicotine also plays a significant role.

Results showed that nicotine e-cigarettes performed even better when compared to non-nicotine quit strategies or placebo devices, with quit rates at least 46% higher.

Nicotine e-cigarettes also pose a lower hazard to those around the smoker, Hartmann-Boyce said.

“It’s not just the person who smokes who is affected by their smoking,” she said. “It’s the people around them who are affected by secondhand smoke, and secondhand vaping is nowhere near as harmful as secondhand smoking either.”

Nevertheless, Hartmann-Boyce warned that e-cigarettes aren’t automatically the best option to quit smoking for every person. Some might not respond as well as others.

It’s also not known how well nicotine vapes would fare compared to newer prescription drugs like varenicline (Chantix), which help smokers quit by binding to nicotine receptors in the brain, Hartmann-Boyce said.

“We don’t have enough studies to compare these drugs to nicotine e-cigarettes to say whether one is better than the other for helping people quit smoking,” she said.

Nicotine e-cigarettes also remain a risk for people who’ve never smoked, as the vapes might get someone hooked on nicotine, researchers said.

“The primary concern about e-cigarettes is their use among people who don’t smoke and wouldn’t have otherwise smoked,” Hartmann-Boyce said. “That doesn’t mean these devices don’t help people quit smoking.”