Breathing and vagal activity
Controlled breathing slows heart rate and supports vagal tone, which helps the body relax.
Jerath et al., 2006, Medical Hypotheses
The science
The science
behind ZenBud.
To understand how ZenBud works, first meet the nerve that helps keep your body calm.
78.6% pilot QoLPeer-reviewed 2025Univ. of Nottingham partnerCE compliant
Meet the vagus nerve
Your body’s built-in brake.
01Vagus Nerve 101
Your vagus nerve is one of the most important communication highways in your body. It runs from your brainstem through your face, neck, heart and digestive system, connecting nearly every major organ to your brain. It’s part of your parasympathetic nervous system, often called the “rest and digest” system. When it’s activated, it helps your body shift from fight-or-flight to rest-and-recover.
02When stress takes over
Under constant stress, the balance tips toward fight-or-flight. That’s when you might notice racing thoughts, restless sleep, a tight chest, or a sense of being stuck in overdrive.
03Why breathing and humming help
Deep breathing, meditation and humming all engage the vagus nerve. ZenBud builds on that same biological principle with precise, non-electrical technology: gentle focused ultrasound at the ear.
So why not just breathe, plunge or meditate? Keep doing them; they help. Your nervous system has many levers. ZenBud’s approach is different: engage the vagus nerve directly, backed by years of independent university research, without a years-long meditation practice to get there.
Illustrative schematic, not a measurement.
Why ultrasound
Not electricity.
Sound, beyond hearing.
Most at-home vagus nerve devices rely on electrical pulses or surface vibration. Those act mostly on the surface of the skin, and often cause tingling or discomfort.
ZenBud uses ultrasound: mechanical energy carried by sound waves above the range of human hearing. They pass gently through the surface of the outer ear to reach the auricular branch of the vagus nerve, without any electrical stimulation.
01
Precision
Ultrasound can be focused on a small, well-defined target: the auricular branch of the vagus nerve at the ear.
02
Comfort
No electrical current is sent through your skin. No shocks, no tingles, no gel.
03
Non-invasive
Sound waves pass through the surface of the outer ear. Nothing breaks the skin and nothing is implanted.
04
Safety
Ultrasound in this frequency range has a long safety record in diagnostic imaging. ZenBud operates at low intensity and is compliant with CE standards.
In short: ZenBud turns decades of neuromodulation science into a simple, non-invasive daily practice for calm.
Our research
Research first.
Honest about results.
We study ZenBud in the open, with university partners and published pilot work, and we tell you exactly what the numbers do and don’t mean.
Peer-reviewed pilot
0%
of participants reported that daily five-minute sessions somewhat or greatly impacted their quality of life.
Study design
0
participants, single-arm, 4 weeks of 5-minute daily sessions. JMIR Neurotechnology, 2025.
Research partner
University of Nottingham
A partnership since 2023 to deepen the understanding of ultrasound auricular vagus nerve stimulation.
Pilot study: n=28, single-arm, 4 weeks. Individual results vary.
Study library
Published, not just promoted.
Seven human studies of ZenBud’s focused-ultrasound approach, six of them sham-controlled, plus four registered trials underway. We count only studies with real participants.
- JMIR Neurotechnology · 2025Pilot study: quality of life after 4 weeks of daily 5-minute sessions28 participants
- Brain Sciences · 2025Labree et al. Sham blinding study20 participants
- Brain Sciences · 2026Hinton et al. Sham blinding study20 participants
- Neuromodulation · 2026Kang et al. Emotional processing, sham-controlled59-person cohort
- Neuromodulation · 2026Falcon-Caro et al. Working memory and tolerability, ultrasound vs electricalSame 59-person cohort
- Neuromodulation · 2026Griffiths et al. Associative memory, ultrasound vs electricalSham-controlled
- bioRxiv (preprint) · 2026Kang et al. Semantic processing. Not yet peer reviewed27 participants
Want the full papers?Researchers, clinicians and practitioners can request access to our science data room.
Request accessRegistered trials: NCT06574971, NCT07091812, NCT07291648, NCT07283913. Studies were run with NeurGear’s university research partners. ZenBud is a general wellness device and is not intended to diagnose, treat, cure or prevent any disease.
The wider field
What the research says about the technology.
The ear-to-brainstem pathway
Brain imaging shows that stimulating the outer ear activates the vagus nerve’s central pathway into the brainstem, the route ZenBud is designed to reach.
Frangos et al., 2015, Brain StimulationHeart rate variability
Studies report improved HRV after auricular VNS, an indicator of better autonomic balance.
Clancy et al., 2014, Brain StimulationUltrasound neuromodulation safety
Low-intensity ultrasound can modulate nerve activity without tissue damage.
Pasquinelli et al., 2019Auricular ultrasound
Pilot studies suggest that ultrasound stimulation of the auricular branch of the vagus nerve may influence vagal signaling and brain networks involved in autonomic regulation, mood and attention.
Goyal et al., 2024, Frontiers in PsychiatryThese studies examine vagus nerve stimulation, breathing and ultrasound neuromodulation in general. They were not conducted on ZenBud and do not establish what ZenBud does. Results vary by study and individual. For educational purposes only.
Safety & standards
Built carefully, close to home.
ZenBud is a general wellness device, built and tested by our own team in Rochester, New York.
- 01
Compliant with CE standards
Meets EU requirements for electronic safety, ultrasound safety and electromagnetic compatibility.
- 02
General wellness device
Not a medical device, and not reviewed or cleared by the FDA.
- 03
Every unit tested
Each headset is hydrophone-tested in Rochester, NY before it ships.
- 04
Non-invasive, drug-free
Low-intensity ultrasound that complements breathing, meditation and sleep routines.
Experts
The experts who love it.
Biohackers, scientists and practitioners who work with the nervous system every day, in their own words.
01 / 08
The ZenBud uses ultrasound to stimulate my vagus nerve so I can roll easy into my next event, keeping me grounded, clear, and focused.
Dave Asprey*Father of Biohacking
DL
I’ve been using vagus nerve simulators for years in my practice, the Zen Bud is by far the easiest device to use, very reliable and our patients love them.
Dr. LawrencePractitioner · verified buyer
SD
I’ve used a lot of the biggest nerve stimulators, but it wasn’t harsh. It was comfortable… Then I got up and I realized how clear I was.
Dr. Sean DrakeDC, MS · Chiropractor
MK
I am impressed by the miniaturised architecture of the device, the user-friendly design, and the robustness of the system… Overall, this product is a major advancement for the field of noninvasive neuromodulation.
Dr. Marcus KaiserPhD, University of Nottingham
Unlocking the nervous system is your key to wellness.
Christine Smith*Functional medicine practitioner & Doctor of Chiropractic
MY
I’ve tried countless tools to optimize recovery and focus. ZenBud surprised me. After just a few sessions, I felt noticeably calmer and more centered. It’s now part of my nightly wind-down.
Dr. Mark YoungDFM, PhD
I’ve really been enjoying ZenBud. It helps me feel more focused and calm throughout the day.
Nathalie Niddam*Certified holistic nutritionist
TA
ZenBud is amazing and so easy to use.
Teemu ArinaBiohacker
Practitioner? ZenBud works alongside the care you already give.
Partner with ZenBud*Paid partner. Individual experiences vary.
Our commitment
Transparency, science and safety. We’re committed to furthering the science of ultrasound vagus nerve stimulation, responsibly, ethically and accessibly.
ZenBud is a general wellness device. It is not intended to diagnose, treat, cure or prevent any disease. Individual results vary.
ZenBud Series 2
Feel the science for yourself.
$459 or 4 interest-free payments of $114.75. If it isn’t right for you, send it back for a full refund.
45-day money-back guarantee1-year warrantyHSA/FSA eligible*Free travel case
