Coloured noise has become enormous on social media — brown noise in particular has accrued millions of posts with claims ranging from “it cured my focus” to “I finally slept through the night.” What is actually true?

First, a definition. White noise contains all frequencies at equal intensity. Pink noise has more energy in the lower frequencies — a gentle roll-off, like steady rain. Brown noise rolls off more steeply, deeper and richer — the inside of a running tumble dryer is a decent approximation.

White noise: the masking evidence

The most defensible use of any background noise is acoustic masking — drowning out disruptive sounds so they don’t pull you out of sleep. Multiple studies support white noise as an effective masker in environments with intermittent noise.6 A 2024 sleep-lab study found pink noise and earplugs both reduced the impact of intermittent noise on sleep architecture, though pink noise had limitations.7 The mechanism is well understood. What you are really buying here is “my partner’s snoring is less audible,” not a pharmacological sleep aid.

Pink noise: interesting, and cautious

This is where it gets genuinely more interesting — and where you need to hold two things at once. Certain closed-loop studies, where brief pulses of pink noise are timed to the up-phase of slow oscillations during deep sleep, have shown enhancement of slow-wave activity and modest improvements in memory consolidation the next day.8 A 2026 paper proposes a mechanism via rapid auditory pathways to the hippocampus.9

That is scientifically interesting. It is not the same as “playing pink noise continuously through a speaker helps you sleep.” The protocols are highly specific — precise timing, lab conditions, EEG monitoring. Continuous passive pink noise is a different intervention, and one 2023 study found overnight exposure could actually reduce performance on some memory tasks.10 The evidence is genuinely mixed.

Brown noise is the most viral, and has the least clinical evidence. As of now, there are no published RCTs on brown noise and sleep.

Brown noise: viral, essentially no trials

Let us be direct. The brown-noise phenomenon is social. There are no published randomised controlled trials on brown noise and sleep as of mid-2026.11 There is anecdotal enthusiasm, some plausible reasoning about low-frequency masking, and no clinical evidence worth citing. It might be pleasant. It might help some people. We do not know, and the people selling it do not know either.

What this might mean for your evening

If you live somewhere noisy, or share a bed with an unpredictable sleeper, a consistent low-level background sound may make a real difference — through masking. Beyond that, choose the colour you find pleasant, because that is roughly as evidence-based as most of the specific-colour claims.

A note. This is general education, not medical advice. Nothing here is a claim about any Mythrae product.

References

  1. Sleep Foundation / SLEEP (2023). White, pink and brown noise: differences and evidence.
  2. Riedy, S. M. et al. (2024). Pink noise and earplugs for mitigating intermittent environmental noise during sleep. SLEEP / Oxford Academic.
  3. Ngo, H. V. et al. (2020). Enhancing slow oscillations and N3 sleep with auditory stimulation during NREM sleep. Nature and Science of Sleep.
  4. Sabaghypour, S. et al. (2026). A hypothesised mechanism for sleep-dependent memory consolidation with auditory stimulation. The Neuroscientist.
  5. Appleby, J. B. et al. (2023). Overnight pink-noise exposure could jeopardise sleep-dependent insight. PMC.
  6. PMC (2025). Are brown, pink and white noise neutral control stimuli? A review.

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