Brainwave entrainment: does it work, do you need a device?

Brainwave entrainment is the idea that a steady rhythm of sound or light can nudge your brain’s own rhythms to match it. The research is mixed: the brain clearly responds to rhythm, but whether that changes how you feel is less certain. Here is how it works, what studies found, and whether you need a device.

What is brainwave entrainment?

Brainwave entrainment is the idea that a steady outside rhythm can lead your brain’s electrical rhythms to fall into step with it. The rhythm can be a pulsing sound, a beat you hear between two tones, or a light that flickers at a fixed rate. If you play a 10 Hz rhythm, the theory goes, your brain moves towards 10 Hz too, and with it towards the state that rate is linked to.

Those states come from the brain wave bands that an EEG, the test that records brain rhythms through the scalp, picks up. Our guide to brain wave types covers each one in detail.

Band	Range	Typical state
Delta	0.5 to 4 Hz	Deep sleep
Theta	4 to 8 Hz	Drowsy, deeply relaxed
Alpha	8 to 12 Hz	Relaxed, eyes closed
Beta	12 to 30 Hz	Alert, busy thinking
Gamma	Above 30 Hz	Intense focus, processing

How does brainwave entrainment work?

Brainwave entrainment works, in theory, by giving your brain a rhythm to follow, and there are three common ways to deliver it:

• Binaural beats: one tone in each ear, for example 200 Hz on the left and 210 Hz on the right. Your brain hears a soft 10 Hz beat that exists in neither sound. They need headphones. Read what binaural beats are for the full explanation.
• Isochronic tones: a single tone switched on and off at a steady rate. The pulse is in the sound itself, so it works on speakers.
• Light and sound devices: glasses or masks with small lights that flicker at a set rate while you keep your eyes closed, usually paired with sound.

The part that is well established is that the brain responds to a steady rhythm. Play a sound that pulses 40 times a second and an EEG shows a clear response at 40 Hz, called an auditory steady-state response. Doctors and researchers use it to test hearing. What is less clear is whether that response changes how you feel or think.

Does brainwave entrainment work?

The honest answer is: sometimes, a little, and not always for the reason claimed. A 2023 systematic review looked at 14 EEG studies of binaural beats. Five found results in line with entrainment, eight found results against it and one was mixed. The authors noted that the studies used very different methods, which makes them hard to compare.

The picture on how people feel is a bit brighter. A 2018 meta-analysis of 22 studies found a medium effect (g = 0.45) of binaural beats on memory, attention, anxiety and pain. A 2025 integrative review of 84 studies from the previous ten years, covering both sound and light, reported improvements in pain, sleep, mood and thinking. It also called for larger samples, proper control groups and randomised trials, which tells you how early this research still is.

So brainwave entrainment may help some people relax or concentrate, but the claim that it sets your brain to an exact frequency is not established. Our article on whether binaural beats work goes through the studies in more depth.

Are brainwave entrainment devices better than apps?

For sound, no study has shown that a dedicated device does anything an app on good headphones does not. Binaural beats and isochronic tones are simple sounds. A phone and headphones play them just as well as a box or a headband.

What a device usually adds is light. Flickering light and sound together can feel stronger, and some studies in the 2025 review used it. But it is also the part that carries real risk: flickering light can trigger seizures in people with photosensitive epilepsy. If you have epilepsy, or have ever had a seizure, do not use a flickering light device without talking to your doctor.

Some devices also show or claim to measure your brain waves. Most apps do not, and that includes Shimmr: it plays sound only, with no light and no EEG, and it does not measure your brain waves.

Is brainwave entrainment safe?

For most healthy adults, listening to brainwave entrainment audio at a low volume is low risk. A quiet level is enough to hear the beat, and loud sound over long sessions can harm your hearing.

Slow rhythms in the Theta and Delta range can make you drowsy, so never listen while driving or doing anything that needs your full attention. Stop if you feel dizzy, anxious or unwell. Brainwave entrainment is not a treatment for any condition. If you are thinking of trying it for a health problem, talk to your doctor.

How can you try brainwave entrainment with sound?

You can try brainwave entrainment with sound in 15 to 30 minutes, lying down or sitting still, at a low volume. Choose binaural beats if you have headphones, or isochronic tones if you want to use a speaker. Our comparison of isochronic tones and binaural beats helps you pick.

In Shimmr, the library has binaural sessions from Delta to Gamma for headphones, such as Deep Focus with a 40 Hz Gamma beat, and isochronic sessions that work on speakers. Shifts glide the beat from one band to another and then hold it, for example Tense → At Ease, from Beta to Theta over 15 minutes. In Sound Canvas you can drag a tone and hear its beat change while it plays.