Gamma and the 40 Hz question

Gamma — above roughly 30 Hz, with 40 Hz as the reference point — is where the most genuinely exciting research in this whole area sits. It is also where the largest gap opens between what has been shown and what gets sold.

Both halves deserve stating properly.

What has actually been demonstrated

Since 2016, Li-Huei Tsai's laboratory at MIT has published a substantial body of work on what they call GENUS — gamma entrainment using sensory stimulus.

In mouse models of Alzheimer's disease, 40 Hz light flicker and/or 40 Hz sound reduced levels of amyloid-beta and tau, appeared to prevent neuron loss, preserved synapses and sustained performance on learning and memory tasks. A striking element is the apparent involvement of microglia — the brain's resident immune cells — and of glymphatic clearance.

Human work has followed. Phase 1 and Phase 2a studies reported that 40 Hz stimulation was safe and well tolerated, and produced entrainment in cortical and subcortical structures. Longer follow-up of daily 40 Hz audiovisual stimulation over two years has been reported as safe and feasible, with a suggestion of slowed cognitive and biomarker decline, particularly in late-onset patients. Cognito Therapeutics, an MIT spinout, has been running a Phase III trial.

This is serious science. It is not fringe, and dismissing it would be as wrong as overselling it.

The four gaps

Now the parts that matter before anyone concludes an audio track is a treatment.

1. Most of the mechanism is from mice. The amyloid, tau and microglial findings are largely rodent results. Mouse models of Alzheimer's have a long history of producing results that do not translate.

2. The human trials are small, and Phase III is not finished. Safety and feasibility in small cohorts is a real finding. It is not efficacy.

*3. It is light and sound.* The GENUS protocol is predominantly audiovisual — a 40 Hz flickering light combined with 40 Hz sound. Audio alone is not the intervention that produced the headline results. We do not ship a flickering light, and we would not: photic stimulation at 40 Hz carries a genuine seizure risk for susceptible people.

4. It is a clinical protocol under supervision. Daily, dosed, in a trial, with monitoring.

What a 40 Hz audio session actually is

It is a tone amplitude-modulated at 40 Hz.

That is not nothing — 40 Hz modulation produces the auditory steady-state response, which is among the most reliable measurements in auditory neuroscience, and is precisely why 40 Hz was chosen as the target in the first place.

But "produces a measurable auditory response" and "clears amyloid" are separated by everything above.

About our session names

We should address this directly, because early working titles for 40 Hz Low-Noise Field and Slow Gamma Maintenance implied biological outcomes the audio cannot establish. The public catalog now uses descriptive names instead.

Those names describe the mechanism the 40 Hz research is investigating, not an effect the audio has been shown to have on you. They are named for the hypothesis. We do not claim they clear tau, and the science page says so in plain terms.

If you want the useful version: these are 40 Hz gamma sessions, well built, on carriers chosen to sit comfortably for the session length. Whether daily 40 Hz audio does anything for long-term brain health is an open question that a Phase III trial may eventually answer. It has not answered it yet.

Gamma outside the clinical story

There is a second, less loaded reason to be interested in this band. Gamma activity is associated with binding — the integration of separate features into a single percept — and with moments of intense, integrated attention.

Flow State Gamma-Alpha Bridge uses phase-amplitude coupling rather than a plain 40 Hz pulse: a fast gamma rhythm whose loudness is governed by a slower one. That nested structure is borrowed from a real feature of cortical activity, where the phase of a slow oscillation modulates the amplitude of a faster one.

We are reproducing that shape in sound. We are not claiming to reproduce it in you.

A practical note: at 40 Hz the modulation is fast enough that you no longer hear separate pulses — it reads as a roughness or buzz in the tone. That is expected. Sessions in this range use gentler envelopes for exactly that reason.

If you are here because of a diagnosis

This needs saying plainly, because it is the most likely reason someone reads this page.

Brainwavest is a wellness tool and not a medical device. It does not diagnose, treat, cure or prevent any condition, and nothing in this catalog is a therapy for Alzheimer's disease or cognitive decline.

If you or someone close to you has a diagnosis, the people to speak to are a clinician and, if the gamma work interests you, the teams actually running the trials — sensory gamma stimulation is being tested under supervision, at defined doses, with monitoring. That is a different thing from a listening session, and we would rather point you at the real thing than imply we are it.