What the evidence actually says
This is the long version. The rest of the site deliberately keeps clear of it, because you do not need any of this to put headphones on, and a page thick with study names is a worse place to arrive on a bad afternoon.
If you want to know what is actually known, though, here it is, including the parts that do not flatter either technique.
Binaural beats
What has been measured
A 2025 systematic review of binaural beat audio in surgical patients included 15 randomized trials. Pooling 14 of them, around 1,050 patients, it found lower anxiety against blank or silent audio, with smaller but real effects on pain and heart rate.
The trials disagreed with each other substantially, so the direction of the effect is more trustworthy than its size. A related 2026 review graded the pain evidence as low certainty, which is a fair word for the whole picture.
Two things worth knowing about that review if you go and read it. Against ordinary non-binaural music, rather than silence, the advantage was marginal and the trials disagreed even more. And its published significance values describe how much the trials differ from one another, not how large the effect is, which is easy to misread.
The study that went the other way
In 2023 a study recruited 1,000 people to take a reasoning test at home. Those who listened to 5 Hz or 15 Hz binaural beats during the second half scored worse than their own baseline, and worse than a group who sat in silence. Classical music and a plain tone caused no such drop. Telling people the sounds would help did not rescue the result.
It was unsupervised home use, which is exactly how most people encounter these.
The honest summary
Small, inconsistent effects. Most often repeated for situational anxiety. Not supported as a way to think better, and at least one large study found it made reasoning worse.
On brainwave entrainment
The usual claim is that the perceived beat pulls your brain activity into a matching band, so a 10 Hz beat produces an alpha state and so on.
Direct tests of that mostly do not find it, or find it inconsistently. Some studies do find modest effects on how people feel or perform while listening, but those do not show entrainment is the reason. Treat it as a proposed mechanism that is contested, which if anything is generous.
Bilateral audio
Where it comes from
Bilateral stimulation is a component of EMDR, a trauma therapy in which a clinician has a client hold a distressing memory in mind while receiving alternating left-right input. That input can be tones, eye movements, or taps on alternating sides.
This matters for reading the evidence, because almost all of the research is about EMDR, most of it is about eye movements rather than sound, and a great deal of it is about the whole therapy rather than the alternating part.
One distinction worth holding onto: EMDR is an eight-phase protocol. Bilateral stimulation is one component of one phase. Listening to bilateral audio is not a smaller version of EMDR. It is that one component with the structure removed.
What has been measured directly
Two small laboratory studies exist.
In one, 18 healthy volunteers received alternating left-right tones during fear extinction. It lowered fear expectancy and reduced a skin-conductance measure of fear a day later.
In the other, an fMRI study of 22 healthy young women, alternating tones increased right amygdala activity and decreased left prefrontal activity while the participants viewed unpleasant images, compared with simultaneous tones or silence. The authors read this as making emotional material more accessible.
Both are mechanism findings in healthy people. Neither is a clinical result, and neither shows that listening to a track treats anything.
EMDR as a whole therapy
Well supported for PTSD, and recommended by the WHO, NICE, ISTSS and the US VA and Department of Defense.
The American Psychological Association is more cautious. Its 2025 guideline lists EMDR as a conditional, second-line option behind cognitive processing therapy, prolonged exposure and trauma-focused CBT. That gap between bodies is itself disputed.
The argument about whether the alternating part does anything
This is the live question, and the site would be taking a side if it gave you only one half of it.
Studies that take EMDR apart to test its components have produced conflicting results. Some found no benefit from the eye movements themselves. A 2013 meta-analysis found a moderate additive effect, d = 0.41, dropping to around 0.3 after adjusting for outliers and publication bias, and not statistically significant among patients with a formal diagnosis. A 2020 meta-analysis of laboratory studies found eye movements outperformed other distracting tasks by only a small margin.
Critics call the alternating element a “purple hat” effect, a term coined by the psychologists Gerald Rosen and Gerald Davison in 2003 for a treatment package that works because of its established components while the credit goes to a novel addition that does nothing. The argument is that EMDR’s results come from exposure and cognitive work, which it shares with other trauma therapies.
The counter-argument is the 2013 figure above, which is a real effect that survived meta-analysis. Both camps have allegiances. Rosen and Pankratz on the sceptical side, de Jongh and Lee on the other.
Almost all of this tested eye movements, not the alternating tones used in audio. For audio specifically, the evidence is thinner still.
So where does that leave bilateral audio
With thinner support than binaural beats have, and two small mechanism studies in healthy volunteers as its direct evidence base.
That is not the same as saying it does nothing. Plenty of people find it helps them, and that experience is real whether or not the literature has caught up with it. It is only to say that the confident claims made for it are running ahead of what anyone has shown.
On doing this alone
EMDRIA’s 2020 guidance on virtual EMDR states that self-administration of EMDR therapy is forbidden under EMDRIA policy, and excludes services offering EMDR self-therapy without live guidance from a trained clinician. Francine Shapiro, who developed EMDR, wrote that attempting self-directed processing can leave a memory dissociated rather than reprocessed.
That is about EMDR therapy, which is the eight-phase protocol, not about listening to a track to settle down. No professional body has said anything about recordings used outside therapy, and we could not find research on self-administered EMDR at all.
The practical distinction is the instruction rather than the audio. Using a track to steady yourself in the present is a different activity from deliberately bringing up a traumatic memory while it plays.
On side effects
EMDR’s safety has been studied far less carefully than its effectiveness. Of 51 randomized trials, only nine mentioned side effects at all and only one measured them systematically. Where they were reported they were usually mild and short-lived.
Those are findings about full EMDR therapy with a clinician, not about audio.
Claims you will meet elsewhere
“It engages both hemispheres.” Interhemispheric communication is one of several competing theories inside EMDR research for why alternating stimulation might help. Researchers say no single mechanism has been established, and the idea comes from clinical eye-movement work rather than from anything about audio.
Brainwave bands. Neuroscientists do group EEG activity into delta, theta, alpha, beta and gamma, but the cutoffs vary from paper to paper. The ranges you see quoted are a common convention, not a law of physiology.
432 Hz and 528 Hz. Claims that these frequencies have special healing properties have no credible support. The numbers come from 1970s numerology rather than from ancient tuning or from acoustics.
If you want to talk to someone
EMDR therapist directories are run by EMDRIA in the United States, the EMDR Association UK, EMDR Europe through its national associations, EMDRAA in Australia, and EMDR Canada.
They list members. They do not vet competence, which is EMDRIA’s own disclaimer about its directory.
Sources
Every source named on this page was retrieved and read during a verification pass. Where a source could not be obtained, the claim that rested on it was cut rather than repeated.
- Xiong et al., Binaural beats for perioperative anxiety and pain, Complementary Therapies in Medicine, 2025
- Klichowski et al., Scientific Reports 13:11079, 2023
- Lee and Cuijpers, Journal of Behavior Therapy and Experimental Psychiatry, 2013
- Houben et al., Journal of Experimental Psychopathology 11(1), 2020
- Rosen and Davison, Behavior Modification 27(3), 300-312, 2003
- Boukezzi et al., Frontiers in Psychology, 2017
- Herkt et al., PLOS ONE, 2014
- EMDRIA, Guidelines for Virtual EMDR Therapy, task group report, 2020
- van Schie and van Veen, Current Opinion in Psychology, 2026