Pink noise is a random signal whose power drops as frequency rises, by about 3 dB per octave, so each octave carries roughly the same energy. It sounds deeper and less harsh than white noise, closer to steady rain or a waterfall, and audio engineers use it to check whether speakers and rooms reproduce all frequencies evenly.
Pink noise has a notable place in sleep research, but in a very specific form. Small laboratory studies have played brief bursts of pink noise timed to the brain’s slow waves during deep sleep, using systems that read brain activity in real time, and reported stronger slow-wave activity and better overnight recall of word pairs in younger and older adults. That is quite different from leaving a pink-noise track running all night. For attention, a 2024 meta-analysis found a small benefit of white or pink noise only in young people with ADHD.
These results are interesting but do not make pink noise a proven sleep aid; persistent sleep problems deserve a conversation with a doctor.