Why is there only a left ear electrode?

1. Traditional Path & Safety Considerations
   1. ZenoWell defaults to left-ear stimulation, following the protocol of traditional implanted vagus nerve stimulation (VNS).
   2. Over 60% of transcutaneous auricular VNS (taVNS) clinical studies use the left ear because:
      • Implanted VNS targets the left cervical vagus nerve;
      • The right vagus nerve has a stronger influence on sinus rhythm, and direct stimulation may increase the risk of sudden heart rate drops.
   3. To minimize such risks, early taVNS studies also chose the left ear.
2. Clinical Benefits
   1. Research shows that left-ear taVNS helps improve sleep, reduce depression, stress, and anxiety, relieve headaches and chronic pain, restore energy, and enhance long-term anti-inflammatory capacity.
3. Right & Bilateral Ear Research
   1. Further studies suggest auricular vagus signals first project to the brainstem before influencing peripheral pathways, meaning the effect on heart rate is indirect.
   2. Trials with right-ear or bilateral stimulation have not shown significant long-term risks.
   3. In most people, right-ear stimulation does not significantly impact heart rate.

👉 Therefore, our default configuration is the left ear electrode. However, for users with special needs and after proper risk evaluation, we also offer a right ear electrode as an option.