We all know that smoking cigarettes is dangerous, and quitting smoking is one of the best things you can do for your health. The problem is quitting nicotine is extremely difficult. But now, there’s a new tool to help people quit—smartphones. The appeal of smartphones is that they are on a person’s body almost all the time and they can serve up apps to people around the world. But can a digital app actually help you quit smoking irl?

To address this question researchers ran a full-scale, long-term, global trial to see how effective a smartphone app is at helping someone quit smoking. The trial worked like this: over a 5-month period, an app designed to help you stop smoking was available for a free download in the Apple App Store in the USA, UK, Australia, and Singapore. The study focused on people over age 18 who smoked daily—some of these people were randomized into an intervention group that received a version of the app that had features designed to help them quit, while other people were randomized into a control group that received a version of the app that only gave them unstructured information about quitting smoking. Both versions of the app recorded the date that a person quit smoking and then followed-up with their progress after 24 hours, 10 days, 1 month, 3 months, and 6 months. The 1 month follow-up was considered the primary outcome of the study. The study was double-blinded—meaning that neither the participants or the researchers knew which group they were in. Now the app designed to help smokers quit had four main features. First, it gave them a decision-aid feature that guided the user through the risks and benefits of different quitting strategies—like nicotine replacement therapy, or hypnosis—to help the user decide which strategy interested them the most so that they could use it along with the app. Second, the app sent out push notifications like daily motivational messages. Third, the app offered a quitting diary that allowed people to record their own notes on their progress. Fourth, the app provided a quitting benefits tracker, which gave information like how much quitting has decreased a person’s risk of lung cancer over time.

So, how well did the app with all these features work? The study included 684 people who were assigned to either the intervention group or the control group. At the 1-month follow-up, 29% of the participants that were a part of the intervention group reported not having had a single cigarette since their quit date. This is compared to 17% of the control group. In fact, the intervention group was more successful than the control group at every other time point in the follow up period, so using the app definitely helped individuals quit smoking.

Further insights from the study revealed that a third of the people tried to quit smoking without additional treatment—like nicotine replacement therapy, hypnosis, or herbal therapy—perhaps because they didn’t want to spend additional time and money on other treatments. Interestingly, though, among individuals who did use additional treatment strategies, there didn’t seem to be any additional benefit. Having said that, the fact that the intervention group received a decision-aid feature did seem to help individuals feel more informed and confident about choosing a strategy to use. The researchers also concluded that using the quitting benefits tracker seemed to be the only predictor that an individual would still be not smoking at 6 months. That said, other features, like the decision-aid feature, may have been more useful at the beginning of a person’s attempt to quit smoking.

So, the bottom line is that a thoughtfully designed smartphone app can help a person quit smoking. When looking for a ‘good’ app a few things to look for include a decision-aid feature, which help you feel informed by guiding you through your strategy options; push notifications, which can help keep you on track by providing frequent motivation and reminders; and a quitting benefits tracker, which can help remind why you decided to quit in the first place.