Getting a good night’s sleep is a struggle for millions of Americans. The CDC estimates that about 15% of people in the U.S. have trouble falling asleep — and that’s just the ones who report it.

In response, more and more people are turning to everything from white noise machines and melatonin to guided meditations, special pillows, and blackout curtains. But one expert says one of the most effective sleep tools out there doesn’t cost a cent.

It’s called the 4-7-8 method, and according to Dr. Andrew Weil, it’s the “most powerful” relaxation technique he knows to promote sleep.

Weil is the founder and director of the Andrew Weil Center for Integrative Medicine at the University of Arizona, and has long promoted a combination of traditional and alternative healing. He says the 4-7-8 breathing method is simple and effective, and for many people, it can help quiet the mind and calm the body — fast.

Here’s how it works:

• Inhale through your nose for a count of four.
• Hold that breath for a count of seven.
• Exhale slowly through your mouth for a count of eight.

That’s it.

What makes the method unique, Weil says, is the long exhale. Compared to techniques like box breathing — which uses equal time for inhale, hold, and exhale — the 4-7-8 method lengthens the out-breath, which can trigger relaxation and lower anxiety.

It may not feel natural at first, and Weil emphasizes that the benefits build with repetition. He recommends doing four cycles at least twice a day. After a month, that can increase to eight cycles per session — but no more. “That’s the absolute maximum,” he says.

Practiced regularly, he says the method can lower heart rate and blood pressure, improve circulation and digestion, and ultimately help people fall asleep more easily. A 2022 study in Physiological Reports backs that up, finding that 4-7-8 breathing reduced heart rate and blood pressure for several minutes. But researchers also caution that long-term data is limited.

Still, for those looking to fall asleep faster or get back to sleep after waking in the night, Dr. Weil says there’s nothing more effective.

“If you get up in the middle of the night for any reason, it is the most effective anti-anxiety technique that I’ve found,” he says.

Part of the reason it works: deep breathing increases melatonin production — that’s the hormone responsible for regulating sleep. It also helps calm the mind by giving it a fixed pattern to focus on, rather than whatever spiral of thoughts or stress might otherwise be racing through.

When we’re anxious, breathing becomes shallow and erratic. Breathing deeply and rhythmically can tell the nervous system to dial back the stress response. Muscles relax, the heart rate slows, and the mind follows suit.

Still, Dr. Weil is clear that the 4-7-8 technique is not magic — it’s a daily practice. It works best when it becomes a habit, not just a last-ditch sleep hack.

“This is a practice,” he says. “You may not experience the benefit the first time, but with repetition, you will.”

The technique has been making the rounds for years but continues to gain attention as more Americans look for simple, drug-free ways to improve their sleep. In a culture where sleep aids, supplements, and expensive gadgets are booming, the appeal of a free, no-equipment-needed method is clear.

And while it may not work instantly for everyone, it’s safe, simple, and takes less than a minute to try.