To summarize all this, we can see that the type of product you choose plays an important role in answering that question – “Can brainwave entrainment damage my brain?” My personal advice as a long-term user of the technology is to Be selective about what brainwave entrainment audios you download from the internet, and make sure to follow the instructions! 
A very pleasurable experience during listening (and often for some time afterwards). As Holosync® changes your brain wave patterns to those of deep meditation, the brain produces several very pleasurable neurochemicals, including endorphins (the same endorphins responsible for “runner’s high”)…as well as several hormones with a profound and positive effect on longevity, aging, stress, and well-being.
Binaural Beats or “binaural tones” are created by playing slightly different frequencies separately into each ear. The difference between the two frequencies stimulates a response in the brain which correlates with this frequency difference. For example, if we present a 100 Hz tone to the left ear and a 105 Hz tone to the right ear, a frequency of 5 Hz is stimulated. This is what is known as the “frequency following response”.

Robert Monroe, a radio producer and executive published a popular book called Journeys Out of the Body about his out-of-body experiences when using brainwave entrainment. He later founded an original brainwave entrainment audio company, Hemi Sync. In 1981, the book Mega Brain by Michael Hutchison brought brainwave entrainment information, techniques, and terminology into the popular press.
If brainwave entrainment leaves you with unwanted side-effects (see below) or discomfort, you’re probably encouraging a range of brainwaves that are already excessive in some area of your brain. The way around this is to get a brain map to see what your brain’s strengths and weaknesses are, and see what (if any) brainwaves could use some encouragement.