40Hz Auditory Stimulation in the Spotlight of Alzheimer's Research
GLYMPHA
Not a comfortable sound.
Still worth trying.
Experience 40Hz stimulation — studied in leading research labs — through Spatial Audio.
Its discomfort is exactly what makes it a clear, distinct acoustic stimulus.
The 40Hz Frequency Under Research
GLYMPHA — the 40Hz Gamma Wave Sound App — is a free iPhone app that lets you experience 40Hz auditory stimulation studied in Alzheimer's research. 40Hz (gamma waves) is the frequency band synchronized during active brain states. In the PNAS 2026 primate study, 7 days of 40Hz auditory stimulation changed cerebrospinal fluid levels of the Alzheimer's disease biomarker amyloid-β42 by approximately 202%, with effects persisting 5+ weeks. While the sound can be monotonous and uncomfortable, GLYMPHA combines background audio and 3D Spatial Audio to make stimulation easier to maintain.
Alzheimer's Disease and 40Hz Auditory Stimulation — What Research Shows
The relationship between 40Hz gamma-frequency auditory stimulation and dementia and Alzheimer's disease has been studied in multiple peer-reviewed papers.
PNAS 2026
Long-Term Primate Study
In Wang et al.'s study using aged rhesus macaques, 7 days of 40Hz auditory stimulation increased the Alzheimer's disease biomarker amyloid-β42 by 202.82 ± 31.85% (p=0.0155) in cerebrospinal fluid, with effects persisting for 5+ weeks after stimulation ended.
Nature 2024
Multisensory Stimulation and the Glymphatic System
Murdock et al. showed that multisensory 40Hz stimulation promotes glymphatic clearance — the brain's waste-removal mechanism linked to dementia — in Alzheimer's disease model mice.
Cell 2019
Visual + Auditory Multi-Sensory Stimulation
Martorell et al. from MIT's Tsai Lab showed that combining visual and auditory 40Hz stimulation improved memory function and reduced amyloid-β and tau pathology in Alzheimer's disease model mice. A foundational paper on 40Hz stimulation in Alzheimer's research.
* This app is not a medical device and is not intended for the diagnosis, treatment, or prevention of any disease. The studies above are animal or clinical research findings and do not prove the effectiveness of this app.
* Some of the studies referenced above (e.g., Cell 2019) used combined visual and auditory multisensory stimulation. This app provides auditory (acoustic) stimulation only and does not include any visual stimulation features.
Key Features of GLYMPHA
01 — WAVEFORM
40Hz Pulse Generation
Defaults to 40Hz. Pulse frequency can be set freely via brainwave band presets—δ (2Hz), θ (6Hz), α (10Hz), β (20Hz), γ (40Hz)—or a slider (0.5–100Hz). Carrier frequency is also adjustable. Choose from sine, square, or triangle waveforms.
02 — SPATIAL
Spatial Audio — 3D Experience
Full 3D audio powered by Apple's PHASE framework. In fixed position mode, place the sound source freely on the XZ plane via a 2D pad and adjust height (Y-axis) by ±2m. With head tracking enabled, spatial audio intensity is adjustable from 0–100%, with automatic wired headphone detection.
03 — FLUCTUATION
Volume Fluctuation
Choose from 5 rhythm patterns—Smooth, Wave, Box, Relax, and Sleep—to vary the volume periodically, reducing monotony and adding natural movement to your listening experience. The variation interval is also adjustable.
04 — BACKGROUND
Background Sound
Choose from pink noise (ideal for focused work) or ocean waves (great for relaxation) to gently wrap around the 40Hz pulse and soften its harshness.
05 — PRESET
Preset Management
Save, overwrite, and manage all your parameter settings as presets. Synced via iCloud across your iPhone and iPad seamlessly. No limit on the number of presets.
06 — TIMER
Sleep Timer
Set an auto-stop timer from 1 to 60 minutes. Perfect for bedtime wind-down, meditation, or the Pomodoro Technique.
When People Use It
Results vary between individuals — the same experience is not guaranteed for everyone.
During Focused Work
Programming, design, writing, studying. Great for building a productive remote-work environment too. Combined with pink noise, it acts as an ambient sound layer.
※ Effects on productivity are still under research
For Relaxation
Short breaks between tasks, winding down before sleep, background audio for meditation or yoga. Works especially well with ocean waves and volume fluctuation.
※ Relaxation effects vary by individual
A New Bedtime Ritual
Set a 15–30 minute timer before sleep. Lie in bed with the lights off and let the sound gently rotate through space as you drift naturally into sleep.
※ Sleep benefits are not guaranteed
Mindfulness Practice
The volume fluctuation feature naturally supports deep breathing practice. Use the timer to structure your sessions intentionally.
※ Scientific effects on meditation are under research
What Users Say
※ The following are illustrative examples of typical use cases. Results vary by individual.
I use it while studying for finals. I used to get distracted by noise in the library, but this works perfectly as ambient sound. The 25-minute timer also helps me do Pomodoro sessions!
I struggled to focus at home while working remotely. Since I started using GLYMPHA, my workspace feels more structured. The rotating sound is refreshing — I've saved my go-to settings as "Work Mode."
I use it during Savasana at the end of my yoga classes. Students often say "that was a different kind of sound experience." The immersion from Spatial Audio is really unique.
I write a lot in cafés, but just noise cancelling felt too quiet. The pink noise mode is just right — I use it almost like background music.
I got it to try something new. Listening to the rotating sound while thinking puts me in a different headspace. I'm not sure about the effects, but it's a genuinely interesting experience.
It's part of my bedtime routine now. I set a 30-minute timer and listen from bed. Hearing the sound slowly rotate helps me relax. I love pairing it with the ocean waves.
Frequently Asked Questions
GLYMPHA is a free iPhone app that delivers 40Hz gamma wave auditory stimulation — studied in Alzheimer's research — through Apple PHASE's 3D Spatial Audio. Combined with background sounds (pink noise, ocean waves) and volume fluctuation patterns, it's designed for a comfortable, consistent listening experience.
40Hz is in the gamma wave frequency band of brainwaves — corresponding to 40 cycles per second. This frequency band is associated with synchronized neuronal activity and has been the focus of significant research in cognitive neuroscience.
In a PNAS 2026 primate study by Wang et al., 7 days of 40Hz auditory stimulation increased the Alzheimer's disease biomarker (amyloid-β42) by approximately 202.82% in cerebrospinal fluid, with effects persisting 5+ weeks. However, this is an animal study; effects in humans are still at the research stage.
Amyloid-β is a protein that accumulates in the brains of Alzheimer's disease patients. The glymphatic system is the brain's waste clearance mechanism, primarily active during sleep, that flushes amyloid-β and other waste products via cerebrospinal fluid. Research is investigating how 40Hz stimulation may influence this pathway (Murdock et al., Nature 2024).
No. GLYMPHA is not a medical device and is not intended for the prevention or treatment of dementia or Alzheimer's disease. The effects of 40Hz stimulation are still at the research stage, and this app is provided as an audio experience tool.
Ready to explore 40Hz for yourself?
Start today.
We'll be honest — it's not for everyone.
But if you're curious about research-backed audio stimulation, it might be worth a try.
About In-App Purchase
- Offered as a non-consumable in-app purchase
- You pay once — no monthly or annual charges of any kind
- Not a subscription. All features remain available permanently after purchase
- Available on all compatible devices signed in with the same Apple Account at no extra cost. After switching devices or reinstalling, use Restore Purchases to recover access
Requires iOS 16.0 or later · iPhone / iPad
Important Notice — This app is an audio experience tool
- Not a medical device — not intended for diagnosis, treatment, or prevention of any condition
- No health benefits are guaranteed
- Do not use if you have epilepsy, hearing problems, or are pregnant
- Stop use immediately if you experience any discomfort
