40 Hz Binaural Beat
40.00 Hz
Nearest note: D♯1, 49 cents above standard tuning
A pulse you hear when each ear is given a slightly different tone. The Alzheimer’s research often cited with it used light and clicks, not binaural beats.
How well is this supported?
A claim that has not been established. Evidence is missing, weak, or limited to small studies.
This number is here because people make claims about it. The entry says what is claimed and what has been tested. It is not advice about health.
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About this number
A binaural beat is what you hear when each ear is given a slightly different tone: the difference between the two, here 40 Hz, is heard as a pulse. 40 Hz is in the gamma band of EEG.
What is said about it
What is said, not what was measured
Proponents say 40 Hz binaural beats raise gamma activity in the brain and help thinking and memory, and often cite research at MIT on Alzheimer’s disease. That research used flickering light and trains of clicks at 40 Hz, not binaural beats, and was done in mice. A trial in 76 people of combined light and sound did not meet its main goal (2024). A 2023 review of 14 studies of binaural beats found that five supported an effect on brain rhythms, eight did not, and one was mixed.
Facts
- Frequency
- 40.00 Hz
- Nearest note
- D♯1, 49 cents above standard tuning
- Kind of statement
- Claim made by practitioners
- Filed under
- Claimed Frequencies
Sources
- 40 Hz stimulation and binaural beats
Cited for what the experiments used and what they found.
H. F. Iaccarino et al., Nature 540 (2016) 230–235. A. J. Martorell et al., Cell 177 (2019) 256–271. M. Hajós et al., Frontiers in Neurology 15 (2024) 1343588. R. M. Ingendoh et al., PLoS ONE 18 (2023) e0286023.
View source: 40 Hz stimulation and binaural beats
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Entries close in pitch
Within 35 cents of this tone, in any octave. A cent is one hundredth of the step between two neighboring piano keys. Being close in pitch does not mean two things are connected.