Dry January has become an annual trend in the past several years, prompting many to abstain from alcohol for the inaugural month of the year.

But does it work?

Experts say it’s great for some to slow down their alcohol intake after one of the most celebratory times of the year. It cuts down on calories, improves sleep and brings an awareness of drinking habits.

But for others a deeper problem exists, and a cold turkey approach could actually be dangerous.

Here are five things to know about Dry January.

1. SOME HISTORY

The U.K.-based group Alcohol Concern, now named Alcohol Change UK, started the trending Dry January challenge in 2013.

In its first year, 4,000 people took part, according to the group, and the hashtag-able trend has grown since then. The group’s latest tracking shows that while 100,000 people signed up on the website in January 2018, millions actually participated. The group projects that 10% of those who drink in the U.K. will take part in the challenge this month and abstain from alcohol.

“Dry January offers a ready-made response to anyone who tries to pressure us to drink,” Alcohol Change UK CEO Richard Piper said in a statement. “Strong evidence tells us that signing up for Dry January helps people — even heavy drinkers — to drink more healthily all year round.”

But experts say the challenge might not be for everyone, especially heavy drinkers, and can even backfire for more moderate drinkers.

2. WHO SHOULD BE WARY?

“How helpful Dry January is may vary from person to person,” said Mark Zissman, a psychologist and clinical director of Lake County, Ill., services at Gateway Foundation treatment centers.

Zissman points to studies that show taking a month off from drinking can help in various ways, improving sleep and resulting in weight loss. But he cautioned those who are heavy drinkers. And more mild or moderate drinkers might find success in a month off from alcohol but then usher in February with even heavier alcohol use, Zissman said.

“Largely, the risks are how much is somebody drinking prior to actually participating in Dry January,” he said. “Alcohol is one of two substances where people can actually die from going through withdrawal.” (This also applies to certain kinds of prescription drugs.) “People forget that.”

3. DRY JANUARY ISN’T TREATMENT

Zissman recommends that heavy drinkers consult professionals before taking part in a Dry January challenge, and to think about why they might want to quit drinking for a month: Is there an addiction? If so, Zissman says treatment can help and should go beyond a January challenge.

Zissman also suggests using the acronym CAGE as a self-assessment tool for alcohol-use disorder. C stands for cut-down attempts in the past. A stands for annoyed: Do you feel annoyed by others commenting on your drinking? G is for guilt felt after drinking. And E is eye-opener: Do you need a drink in the morning or notice other physical dependence?

4. WHO BENEFITS?

Zissman said that for many, Dry January can be a healthy endeavor.

“Maybe they find they rely on (alcohol) a little bit too much, but they don’t necessarily have a problem,” he said.

Zissman said more research is needed, but there’s some that shows the Dry January challenge can lead to drinking less for several months afterward.

Besides health benefits, Dry January participants report to the group that they save money.