Isochronic Tones: What They Are, What People Claim, and What the Evidence Shows

Search any music streaming service or video site for "focus music," "deep sleep frequencies," or "brainwave meditation," and you will soon find tracks built from a sharp, regular pulsing sound. Many of them are labelled "isochronic tones." The sellers and channel owners behind these tracks often make large promises: better concentration, faster sleep, lower anxiety, a meditative state on demand, even relief from headaches or help with learning. The idea behind all of these promises is the same. If a sound pulses at a particular rate, the story goes, your brain will start to pulse at that rate too, and different rates correspond to different mental states.

This article explains what isochronic tones actually are as sounds, where the underlying idea of "brainwave entrainment" comes from, what people who use and sell them claim, and what laboratory research has found so far. The short version is that isochronic tones are a real and well-defined kind of sound, the brain really does produce measurable electrical responses to rhythmic sound, but the leap from "the brain responds to a rhythm" to "this track will make you calmer, smarter, or better rested" is supported by very little good evidence. The research base on isochronic tones specifically is tiny, and most of the claims you will see online go far beyond it.

What an isochronic tone is

An isochronic tone is a single tone that is switched on and off at regular, evenly spaced intervals. The word "isochronic" comes from Greek roots meaning "equal time," and that is the defining feature: the pulses are equally spaced. In the simplest version, a tone of one pitch (say, a few hundred hertz) is turned fully on, then fully off, then on again, many times per second. Because the sound drops all the way to silence between pulses, the listener hears a distinct, sharp beat rather than a gentle wobble.

Two numbers describe any isochronic tone:

• The carrier or tone frequency. This is the pitch of the sound itself, measured in hertz (cycles per second). A tone of 200 Hz sounds low; a tone of 1,000 Hz sounds noticeably higher.
• The pulse rate or repetition rate. This is how many times per second the tone switches on and off. A pulse rate of 10 Hz means ten pulses every second.

Commercial tracks almost always advertise the pulse rate, because that is the number that is supposed to match a "brainwave" state. A track sold for relaxation might pulse at around 10 Hz; one sold for "focus" might pulse faster; one sold for sleep might pulse slower. Many tracks layer the pulses under music, rain sounds, or ambient pads so that they are less harsh to listen to.

Wikipedia's article on the topic describes isochronic tones as regular beats of a single tone that are used alongside monaural beats and binaural beats in the practice called brainwave entrainment. Some researchers classify all three as subtypes of a broader category called auditory beat stimulation.

How isochronic tones differ from binaural and monaural beats

Isochronic tones are often discussed together with two other kinds of rhythmic sound, and the differences matter because the research on each is not interchangeable.

Beats in physics. When two tones of slightly different frequency are played together, their sound waves alternately reinforce and cancel each other. The result is a sound whose loudness rises and falls at a rate equal to the difference between the two frequencies. Two tones of 400 Hz and 440 Hz played together will produce a loudness fluctuation at 40 Hz. This is an ordinary acoustic phenomenon, familiar to anyone who has heard two slightly out-of-tune guitar strings "wah-wah" against each other.

Monaural beats. When two such tones are combined into a single sound before they reach the ear, the result is called a monaural beat. The beating is physically present in the sound wave. It can be played through speakers, and both ears hear the same thing.

Binaural beats. When one tone is played to the left ear and a slightly different tone to the right ear through headphones, there is no physical beat in either ear. Each ear hears a steady tone. Yet many listeners perceive a beat at the difference frequency anyway. This is an auditory illusion created inside the brain, where signals from the two ears are combined. A 2015 review in Frontiers in Psychiatry by Leila Chaieb and colleagues notes that binaural beats are thought to be processed centrally, probably in the superior olivary nuclei of the brainstem, and are only perceived when the beat frequency is low and the carrier tones are below about 1,000 Hz. Binaural beats were brought to wide attention by Gerald Oster's 1973 article "Auditory beats in the brain" in Scientific American.

Isochronic tones. An isochronic tone is different from both. It is not made by combining two frequencies at all. It is one tone switched on and off. The rhythm is physically present in the sound, like a monaural beat, but the pulses are sharper because the sound drops to silence between them rather than smoothly swelling and fading.

The table below summarises the differences.

Isochronic tones are sometimes promoted as "stronger" than binaural beats because the rhythm is more obvious to the ear. That is true in the plain sense that the pulses are easier to hear. Whether it means anything for the brain or for how you feel is a separate question, discussed below.

The idea behind it: brainwaves and entrainment

What "brainwaves" are

The electrical activity of the brain can be recorded from the scalp with electroencephalography (EEG). The German psychiatrist Hans Berger published the first human EEG recordings in 1929. EEG traces show rhythmic fluctuations, and researchers group these rhythms into frequency bands. The usual labels are:

The boundaries vary somewhat between textbooks, and the associations in the right-hand column are tendencies, not rules. Alpha activity, for example, is typically seen in relaxed people and at the very start of light sleep, but it is not a switch that turns relaxation on.

This is the first place where popular claims about isochronic tones often go wrong. The bands are categories that scientists use to describe a very complex signal. At any moment, a person's EEG contains activity at many frequencies at once, coming from different brain regions doing different things. "Being in alpha" is a simplification. Changing the strength of activity in one band does not automatically produce the mental state loosely associated with that band.

What "entrainment" means

Entrainment, in physics and biology, means that one rhythmic system falls into step with another. A familiar example is how pendulum clocks mounted on the same wall can gradually synchronise. In neuroscience, the term is used for the observation that some brain activity locks onto the rhythm of a repeating stimulus.

That part is real and well documented. When a person hears a sound that is modulated at a steady rate, the auditory system produces a measurable electrical response at that same rate. This is called the auditory steady-state response (ASSR). It is used clinically and in research. The response is known to be especially strong for stimulation rates around 40 Hz. The Chaieb review summarises several findings about it: the response is larger for lower carrier tones (one study found the response at a 250 Hz carrier was about three times larger than at 4,000 Hz), and monaural beats produce stronger, more widely detectable responses than binaural beats. A 2005 study by Schwarz and Taylor in Clinical Neurophysiology recorded a 40 Hz response to binaural beats with low carrier tones, but the response disappeared with carriers above about 3,000 Hz, whereas responses to monaural beats were still detectable at those higher carriers.

So it is fair to say that rhythmic sound, including isochronic pulses, can drive a matching electrical response in the auditory parts of the brain.

The leap that the marketing makes

The brainwave entrainment industry takes this real phenomenon and extends it in several steps:

1. Rhythmic sound produces a matching response in the brain. (Well supported.)
2. This response spreads beyond the auditory system and shifts the brain's overall activity toward the stimulation frequency. (Contested and inconsistent.)
3. Shifting overall activity toward a frequency band produces the mental state associated with that band. (Largely untested and conceptually shaky.)
4. Therefore a 10 Hz track will relax you, a 4 Hz track will put you to sleep, and a faster track will make you focus. (Not established.)

Each step is a bigger claim than the last. The research reviewed below mostly addresses steps one and two. Very little addresses steps three and four in a rigorous way, and almost none of it uses isochronic tones specifically.

Where isochronic tones came from

Unlike binaural beats, which have a clear starting point in nineteenth-century acoustics and Oster's 1973 article, isochronic tones do not have a well-documented origin. There is no landmark paper that introduced them and no accepted inventor. Some websites name particular individuals as their discoverer, but these claims trace back to commercial pages and could not be confirmed in any independent source, so they are not repeated here.

What can be said is that the broader idea of driving brain rhythms with rhythmic stimulation is older than consumer audio. Rhythmic flashing light has long been used in clinical EEG testing, where flashing a light at the eyes can produce an EEG response at the flash rate (a phenomenon known as photic driving). Devices that combine flashing lights with pulsing sounds, usually called audio-visual entrainment or "light and sound machines," were sold to the public in the late twentieth century. Isochronic tones are, in effect, the audio half of that idea, packaged as something anyone can play from a phone.

The explosion of interest in isochronic tones is mostly an internet phenomenon. Free audio-editing software makes them trivially easy to create, and streaming platforms reward long, loopable tracks that people play while working or sleeping. That combination has produced an enormous volume of isochronic content with very little connection to any research.

What proponents claim

Claims vary widely between sellers, but they tend to cluster around the following:

• Focus and concentration. Faster pulse rates in the beta or gamma range are marketed as study aids or productivity tools.
• Relaxation and stress relief. Alpha-range tracks, often around 10 Hz, are sold as a quick route to calm.
• Sleep. Slow theta and delta tracks are sold as sleep aids.
• Meditation. Tracks are marketed as a shortcut into deep meditative states that would otherwise take years of practice.
• Mood. Some products claim to lift depression or reduce anxiety.
• Pain, headaches, and other health conditions. Some sellers go further and suggest benefits for migraines, attention deficit disorders, or other medical problems.
• Superiority over binaural beats. Isochronic tones are frequently promoted as more powerful because their pulses are more distinct and because they do not require headphones.

Some of these claims are framed modestly ("may help you relax"), and some are framed as near-medical promises. Many come with specific-sounding numbers, such as a precise frequency for a precise state, that are not drawn from any published research.

It is also worth noting what users themselves report. Plenty of people say they find pulsing tracks helpful for studying or winding down. Those reports are real experiences and deserve to be taken seriously as experiences. The scientific question is whether the pulsing rhythm itself is what produces the effect, or whether the effect comes from things that any calm, steady background sound would provide: masking distracting noise, giving the listener a cue that it is time to work or sleep, and the expectation that the track will help.

What the research actually shows

How much research exists

The Wikipedia article on isochronic tones states plainly that there has been very little research supporting claims of health benefits from listening to them. That assessment is borne out by the reviews.

A 2021 literature review by Sandro Aparecido-Kanzler, Francisco Cidral-Filho, and Rui Prediger, published in the Revista Mexicana de Neurociencia, set out to examine the effects of binaural beats and isochronic tones on brain wave modulation. The authors searched PubMed, MEDLINE, LILACS, and ScienceDirect. Of the studies that met their criteria, 15 (about 88 percent) used binaural beats, and only two (about 12 percent) used isochronic tones. In other words, even a review that was specifically looking for isochronic tone research found only a couple of studies.

That imbalance is important. When you see an article or product page saying that "research shows" brainwave entrainment works, the research being described is almost always about binaural beats. Binaural beats and isochronic tones are different stimuli processed in different ways, so results from one cannot simply be transferred to the other.

EEG studies: does the brain follow the beat?

The most direct question is whether isochronic tones change brain activity at all. A 2024 study by Typhanie Dos Anjos, Franck Di Rienzo, Charles-Etienne Benoit, Sebastien Daligault, and Aymeric Guillot, published in the journal Neuroscience, compared binaural beats, white noise, and a newer form of auditory beat stimulation inspired by isochronic tones. According to the abstract, binaural beats and white noise both increased oscillatory power in the EEG gamma band, while the isochronic-inspired stimulation produced larger changes in EEG power overall (p < 0.001). Over time, the isochronic-inspired stimulation showed a progressive increase in normalised EEG power compared with binaural beats, and it also produced changes in the alpha band, including a gradual decrease in alpha power over time.

This is an interesting result. It suggests that a sharp, physically present rhythm may drive measurable changes in EEG more strongly than a binaural illusion does, which fits with what is known about the auditory steady-state response. But several points need to be kept in mind:

• The study measured EEG power, not mood, sleep, attention, or any outcome a listener would care about.
• The stimulus was described as "inspired by" isochronic tones, not necessarily identical to commercial tracks.
• One of the reported findings is a decrease in alpha power, which is the opposite of what an "alpha relaxation" track would claim to do.
• A single study, however well run, needs independent replication before strong conclusions are drawn.

Earlier work on monaural beats points in a similar direction. A study by Becher and colleagues in the European Journal of Neuroscience recorded brain activity from electrodes placed inside the skulls of epilepsy patients who were already being monitored for surgery. It found that the largest increases in power followed 40 Hz monaural beats, while some other beat conditions (5 Hz monaural and 80 Hz binaural) produced decreases in power and synchronisation. That is evidence that the brain responds to rhythmic sound in complex, frequency-dependent ways, not that it simply "follows" whatever rhythm is played.

What happens with binaural beats, the best-studied relative

Because binaural beats have been studied far more, they are the best available guide to what "brainwave entrainment" audio can and cannot do. The results are mixed.

A 2023 systematic review in PLOS ONE by Ruth Maria Ingendoh, Ella Posny, and Angela Heine asked whether binaural beats actually entrain brain activity, as measured by EEG. They included 14 studies. Five reported results consistent with the entrainment hypothesis, eight reported contradictory results, and one reported mixed results. The authors stressed that the studies were very heterogeneous in how they delivered the beats, how they designed the experiments, and how they analysed EEG, and they called for standardised methods before reliable conclusions can be drawn.

On behavioural outcomes, a 2019 meta-analysis in Psychological Research by Miguel Garcia-Argibay, Miguel Santed, and José Reales pooled 22 studies yielding 35 effect sizes on memory, attention, anxiety, and pain perception. They found an overall medium effect size (Hedges' g = 0.45) for binaural beats. They also reported that the size and direction of the effect depended on the beat frequency, how long people were exposed, and whether exposure happened before or during the task.

These two reviews can look contradictory, but they are measuring different things. The meta-analysis looked at whether people performed or felt differently after listening. The systematic review looked at whether their EEG actually showed entrainment. It is possible for listening to a sound to have small effects on mood or performance without those effects being caused by entrainment at all. Any pleasant, steady sound might have some effect on anxiety, for example, because of relaxation, distraction, or expectation.

The 2015 Chaieb review lists several reasons for contradictory findings in auditory beat research: effects tend to be weak and short-lived, few studies measured brain activity directly with EEG or MEG, methods vary so much that studies are hard to compare, and factors such as carrier frequency, stimulation length, background noise, the listener's age, and prior meditation experience all seem to matter. The review also notes incomplete reporting of stimulation settings in some studies, which makes replication difficult.

Some individual results reported in that review illustrate the variety. One anxiety study found a 26.3 percent drop in anxiety scores with binaural beats compared with 11.1 percent with placebo audio. A memory study found that a single 30-minute session of 7 Hz binaural beats decreased immediate recall, while another protocol using 5 Hz beats twice a day for 15 days increased the number of words recalled. A pilot study in children with ADHD found no significant effect on attention. The picture is not one of a reliable tool that does what the label says.

Clinical trials of isochronic tones

The closest thing to a clinical trial of isochronic tones is a small randomised study published in December 2023 in the journal Exploration of Neuroprotective Therapy by Sandro Kanzler, Francisco Cidral-Filho, Beatriz Kuerten, and Rui Prediger. Healthy adults were assigned to listen at home, via an app, for 20 minutes a day for 21 days to one of four sounds: white noise (the control), binaural beats, isochronic tones, or a combination of binaural beats and isochronic tones, all at 10 Hz. The researchers measured EEG with a four-channel consumer headset, along with questionnaires on depression, anxiety, and stress (the DASS-21), sleep quality (the PSQI), salivary cortisol, heart rate, and blood pressure.

The study reported some improvements. Total DASS-21 scores fell significantly within the binaural beat group and within the isochronic tone group, and some sleep quality scores improved. The authors concluded that the protocols could help with mood and sleep.

However, a careful reading reveals serious limitations:

• Small sample. Forty-eight volunteers were recruited, nine were excluded, two dropped out because of COVID-19 quarantine, and the paper reports 37 as the final sample while also describing further withdrawals. Group sizes were therefore small.
• A lenient threshold for significance. The study treated p-values up to 0.10 as significant, rather than the more common 0.05. This doubles the tolerance for false positives.
• Within-group comparisons. Most of the reported improvements were before-and-after changes within each group, not comparisons against the white-noise control. Many things improve over three weeks in a study where people expect to feel better, so within-group change does not show that the specific sound caused the improvement.
• Many outcomes, no correction. Numerous outcomes and subscales were tested without adjusting for multiple comparisons, which raises the chance that some "significant" results are flukes.
• Self-reported outcomes. Mood and sleep were measured by questionnaires, which are sensitive to expectation.
• Cortisol showed no significant group differences. The one objective stress marker did not clearly change.

The authors themselves acknowledged the small sample, the disruption of the pandemic, the thin evidence base, and the need for larger trials before any clinical use. Taken together, this study is best described as exploratory. It does not establish that isochronic tones improve mood or sleep.

The 40 Hz research that is sometimes cited

Some brainwave entrainment marketing points to high-profile research on 40 Hz stimulation and Alzheimer's disease. That research is real, but it is often misrepresented.

In 2019, a team in Li-Huei Tsai's laboratory at the Massachusetts Institute of Technology published a study in the journal Cell led by Anthony Martorell. In mice bred to develop Alzheimer's-like pathology, the team exposed animals to a 10 kHz tone pulsed at 40 Hz for one hour a day for seven days. They reported improved spatial and recognition memory and reduced amyloid in the auditory cortex and hippocampus. The tone also reduced a form of tau protein in a different mouse model. Combining 40 Hz sound with 40 Hz flickering light had broader effects than either alone. That work built on an earlier 2016 study from the same group, by Iaccarino and colleagues, that used flickering light.

A 40 Hz pulsed tone is, technically, a kind of isochronic stimulus, which is why it sometimes appears in isochronic tone marketing. But the findings come from mice, not people. Coverage of the work also reported that many of the benefits faded when treatment stopped for a week. Human trials of 40 Hz sensory stimulation are a separate, ongoing research area, and their results should be judged on their own terms, not borrowed to support claims about sleep or focus tracks. Nothing in this research shows that listening to pulsing audio helps healthy people concentrate or sleep.

Summary of the evidence

What better research would need to look like

Because the existing evidence is so thin, it helps to spell out what a convincing study of isochronic tones would involve. The weaknesses described above point directly to the fixes.

A proper control sound. The most informative comparison is not isochronic tones versus silence, but isochronic tones versus a closely matched sound that does not pulse: the same carrier tone played steadily, or the same track with the pulses smoothed out. Only that comparison can separate the effect of the rhythm from the effect of listening to a sound at all.

Blinding. Listeners should not know which version they are hearing, and the researchers scoring the outcomes should not know either. That is harder with isochronic tones than with many interventions, because the pulses are audible, but it can be approached by telling all participants that they are receiving one of several "active" sounds.

Between-group comparisons. The key result should be whether the pulsed group improved more than the control group, not whether each group improved compared with its own starting point.

Pre-registration and conventional statistics. Stating the main outcome in advance, using the usual significance threshold, and correcting for multiple outcomes all reduce the risk of finding chance results.

Objective outcomes alongside questionnaires. Sleep can be measured with laboratory or wearable recordings; attention and memory can be measured with standardised tasks. These are less vulnerable to expectation than self-report alone.

Linking brain response to experience. The most interesting scientific question is whether people whose EEG responds strongly to the pulses are the same people who report feeling different. If the two are unrelated, the entrainment explanation is in trouble even if some listeners benefit.

Standard reporting. As the Chaieb and Ingendoh reviews both stress, studies need to report the carrier frequency, pulse rate, pulse shape, volume, duration, and listening conditions in full, so that others can repeat them.

Until studies of this kind are done, the honest position is that the claims are untested rather than disproven. That distinction matters: it leaves room for future evidence, but it also means that no current product can say it has been shown to work.

Why people may still feel an effect

Saying that the evidence does not support specific claims is not the same as saying that people who like these tracks are imagining things. Several well-understood factors can make any steady background audio feel helpful:

• Noise masking. A continuous sound can cover distracting noises, such as conversations, traffic, or a neighbour's television. This can genuinely help concentration and sleep, regardless of whether the sound pulses.
• Routine and cueing. If you always put on the same track when you start work or go to bed, the track becomes a signal to your brain that it is time to do that activity. This is ordinary habit formation.
• Expectation. Expecting a sound to help you relax can make you relax. Expectation effects are powerful in any intervention where outcomes are self-reported.
• Taking time out. Sitting quietly for 20 minutes with your eyes closed, which is what many entrainment sessions involve, is itself relaxing.
• Enjoyment. Some people simply like the sound, and doing something you enjoy can improve mood.

These explanations predict that a well-matched placebo sound, such as steady noise or a non-pulsed version of the same track, would work about as well. Testing that prediction properly requires studies that compare pulsed and non-pulsed versions, keep listeners unaware of which is which, and use objective outcomes. Such studies are largely missing for isochronic tones.

Safety notes

For most people, listening to isochronic tones is about as safe as listening to any other audio. There are, however, a few sensible cautions.

Volume and hearing

The main realistic risk from any audio played through headphones for long periods is hearing damage from excessive volume. The World Health Organization and the International Telecommunication Union published a joint standard for "safe listening" devices (ITU-T H.870). It sets a reference weekly sound allowance for adults equivalent to 80 decibels for 40 hours a week, with a stricter allowance for children and sensitive users of 75 decibels for 40 hours a week. WHO's consumer advice for personal audio devices includes keeping the volume below about 60 percent of maximum. People who play entrainment tracks all night, or for many hours a day, should keep the volume low. Because isochronic tones consist of sharp on-off pulses, some listeners find them harsh at higher volumes; there is no reason to play them loudly.

Epilepsy and flashing lights

You may see warnings that brainwave entrainment is dangerous for people with epilepsy. The best-documented concern relates to flashing light, not sound. According to the UK charity Epilepsy Society, around 3 percent of people with epilepsy have photosensitive epilepsy, in which seizures can be triggered by flashing or flickering light. Common triggers fall between 3 and 30 flashes per second, and the most likely range is about 16 to 25 flashes per second. Most people who develop photosensitive epilepsy do so between the ages of 7 and 19.

This is relevant because some entrainment products, including light-and-sound machines and some videos, pair isochronic pulses with flashing lights or flickering visuals, often at exactly those rates. Anyone with epilepsy, or with a history of seizures, should avoid flashing-light entrainment devices and flickering videos unless a doctor has said otherwise. Evidence specifically about audio-only isochronic tones and seizure risk is very limited, so people with epilepsy who are curious about audio entrainment should talk to their doctor first.

Not a substitute for treatment

The most important safety point is indirect. If someone uses entrainment audio instead of seeking help for depression, anxiety, insomnia, attention problems, chronic pain, or any other health condition, the delay can cause real harm. Isochronic tones have not been shown to treat any medical or psychiatric condition. Anyone dealing with persistent symptoms should talk to a doctor.

Situations to avoid

Because many tracks are designed to make listeners drowsy, common sense suggests not using them while driving, operating machinery, or doing anything else that requires full alertness.

Common misconceptions

"Isochronic tones are proven to work because science shows the brain follows rhythms." The brain's auditory system does respond to rhythmic sound. That is a long way from showing that a track will change your mental state. The behavioural and clinical evidence specific to isochronic tones is minimal.

"Research on binaural beats applies to isochronic tones." The two are different stimuli. Binaural beats are an illusion created when the brain combines different tones from each ear; isochronic tones are a physical rhythm in a single sound. Findings from one do not automatically transfer to the other.

"Each frequency corresponds to a precise mental state." EEG bands are broad categories, the boundaries between them are approximate, and the brain produces many frequencies at once. Claims that one precise number produces one precise state, such as a particular frequency for creativity, have no basis in published research.

"Stronger EEG response means stronger effect." A larger EEG response to a sound is just that: a larger response. It does not necessarily translate into feeling or performing differently. In the 2024 Neuroscience study, the isochronic-inspired stimulus produced bigger EEG changes, but those included a decline in alpha power, the opposite of what an "alpha relaxation" track would promise.

"The 40 Hz Alzheimer's research proves pulsing sounds are good for the brain." That research was done in mice under specific laboratory conditions, and its benefits faded when stimulation stopped. It does not show that consumer tracks improve memory, focus, or brain health in people.

"If it's on a major platform with millions of views, it must be effective." Popularity reflects how easy these tracks are to make and how well long, loopable audio performs on streaming platforms, not evidence of effect.

How to evaluate an isochronic tone product

If you are considering an isochronic tone app or track, a few questions can help you judge the claims:

• Does it cite specific studies? If so, are those studies about isochronic tones, or about binaural beats, flickering lights, or mice?
• Are the claims proportionate? "Some people find this relaxing" is honest. "Reprograms your brain" or "cures insomnia" is not supported.
• Is there a free alternative? If you just want steady background sound for focus or sleep, ordinary noise, ambient music, or a fan may do the same job.
• Is it asking you to stop treatment or buy expensive upgrades? Those are red flags.
• Does it flash lights? If you have epilepsy or a history of seizures, avoid flashing products.

Frequently asked questions

Are isochronic tones dangerous? For most people, listening at a sensible volume is not known to be harmful. The main risks are hearing damage from loud, prolonged listening; seizure risk for people with photosensitive epilepsy if the audio is paired with flashing lights; and the indirect harm of using audio instead of seeking appropriate treatment.

Do isochronic tones work better than binaural beats? They may produce a stronger measurable EEG response, according to limited research. Whether that leads to any meaningful difference in how people feel or perform has not been properly tested.

Do I need headphones? No. Because the rhythm is physically present in the sound, isochronic tones can be played through speakers. Binaural beats, by contrast, require headphones.

Can isochronic tones help me sleep? One small 2023 trial reported some improvement in sleep questionnaire scores, but its design had significant weaknesses. Steady background sound in general may help some people sleep by masking noise, and that effect does not depend on the sound pulsing. If you have ongoing sleep problems, talk to a doctor.

Can they help with ADHD, depression, or anxiety? There is no reliable evidence that isochronic tones treat any of these conditions. Effective treatments exist for all three, and a doctor can help you find the right one.

What pulse rate should I use? There is no evidence-based answer, because there is no evidence that particular pulse rates reliably produce particular states. If you enjoy a track and it does not cause discomfort, the specific number is unlikely to matter much.

Why do some people swear by them? People's experiences are real, and steady sound can help with masking noise, setting routines, and relaxing. Expectation also plays a role. These effects can be genuine without depending on brainwave entrainment.

Is anyone still researching this? Yes. Auditory beat stimulation remains an active research area, including studies comparing isochronic-style stimuli with binaural beats and research on 40 Hz sensory stimulation. Better-designed studies, with proper controls and standardised methods, may clarify the picture in the future.

The bottom line

Isochronic tones are a genuine, precisely defined kind of sound: one tone, switched on and off at equal intervals. The brain does respond electrically to rhythmic sound, and there is some early evidence that sharp pulses like these may drive EEG changes more strongly than binaural beats do. But almost every popular claim about isochronic tones, from better focus to deeper sleep to relief from anxiety, rests either on research about other kinds of stimulation or on no research at all. A 2021 review found only two studies of isochronic tones, and the only clinical trial, published in 2023, was small and used lenient statistical methods.

If you enjoy these tracks and they help you settle into work or sleep, there is no reason to stop, as long as you keep the volume reasonable and avoid flashing-light versions if you have epilepsy. Just treat them as background sound you happen to like, not as a proven technology for changing your brain, and see a doctor about any health problem that persists.

Sources

• Isochronic tones (Wikipedia)
• Beat (acoustics) (Wikipedia))
• Aparecido-Kanzler S, Cidral-Filho FJ, Prediger RD. Effects of binaural beats and isochronic tones on brain wave modulation: Literature review. Revista Mexicana de Neurociencia, 2021
• Dos Anjos T, Di Rienzo F, Benoit C-E, Daligault S, Guillot A. Brain wave modulation and EEG power changes during auditory beats stimulation. Neuroscience, 2024
• Kanzler SA, Cidral-Filho FJ, Kuerten B, Prediger RD. Effects of acoustic neurostimulation in healthy adults on symptoms of depression, anxiety, stress and sleep quality: a randomized clinical study. Exploration of Neuroprotective Therapy, 2023
• Ingendoh RM, Posny ES, Heine A. Binaural beats to entrain the brain? A systematic review. PLOS ONE, 2023
• Garcia-Argibay M, Santed MA, Reales JM. Efficacy of binaural auditory beats in cognition, anxiety, and pain perception: a meta-analysis. Psychological Research, 2019
• Chaieb L, Wilpert EC, Reber TP, Fell J. Auditory beat stimulation and its effects on cognition and mood states. Frontiers in Psychiatry, 2015
• Becher A-K et al. Intracranial electroencephalography power and phase synchronization changes during monaural and binaural beat stimulation. European Journal of Neuroscience
• Martorell AJ et al. Multi-sensory gamma stimulation ameliorates Alzheimer's-associated pathology and improves cognition. Cell, 2019 (MIT DSpace record)
• WHO-ITU. Safe listening devices and systems: a WHO-ITU standard
• Epilepsy Society: Photosensitive epilepsy