If you've been reading up on vagus nerve stimulation (VNS), you've probably come across the advice to only stimulate the left side of the neck. It’s one of the most common questions we get: “I thought you’re only supposed to stimulate the left side?”
Here’s the truth: that recommendation is based on older, invasive VNS research, and it doesn’t actually apply to the non-invasive techniques being used today—especially those that stimulate the auricular (ear) or cervical (neck) branches of the vagus nerve externally.
Let’s break it down.
⚙️ Why the Left Side Was Preferred in Early VNS Research
In invasive VNS therapy, where a device is surgically implanted around the vagus nerve in the neck, researchers historically targeted the left vagus nerve to avoid the theoretical risk of heart-related complications—especially bradycardia (a slowed heart rate).
That’s because the right vagus nerve has more direct innervation of the sinoatrial (SA) node of the heart, which regulates heart rhythm. Stimulating the right side internally with an implanted device raised concerns that it could interfere with the heart’s electrical system (Yuan & Silberstein, 2016).
As a result, left-side preference became the standard—not because right-side stimulation was proven dangerous in all cases, but because it was a conservative, risk-averse approach in surgical contexts.
🔬 What the Research Says About Non-Invasive Right-Side Stimulation
When it comes to non-invasive VNS (nVNS)—like stimulation delivered through the ear or surface of the neck—the evidence tells a different story.
Modern research shows that stimulating the right side externally is no more dangerous than stimulating the left side, especially when it’s done at safe intensities and durations.
A 2019 study published in Brain Stimulation investigated bilateral transcutaneous auricular vagus nerve stimulation (taVNS) and found no adverse cardiovascular effects, even with right-sided or bilateral stimulation (Frangos et al., 2015; Badran et al., 2018). In fact, several taVNS studies now routinely stimulate both sides or choose the right side specifically—especially in applications involving depression, anxiety, and epilepsy.
In another 2020 clinical trial using non-invasive cervical VNS on the right side (Goyal et al., Frontiers in Neurology), no bradycardia or cardiac distress was reported, and HRV (heart rate variability) improvements were observed without safety concerns.
💡 Bottom Line
So, do you have to avoid stimulating the right side of your vagus nerve?
No—at least not with non-invasive devices. The old surgical rule doesn’t apply here.
Non-invasive VNS—whether auricular or cervical—has been shown to be safe on either side in modern clinical trials, with no increased risk of heart or GI complications from right-side stimulation. If anything, right-side stimulation might even be beneficial for certain use cases.
As always, if you have an underlying heart condition or specific concerns, talk to your healthcare provider. But rest assured: the right side is no longer off-limits when it comes to safe, effective, non-invasive vagus nerve stimulation.
🧠 References
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Frangos, E., Ellrich, J., & Komisaruk, B. R. (2015). Non-invasive Access to the Vagus Nerve Central Projections via Electrical Stimulation of the External Ear: fMRI Evidence in Humans. Brain Stimulation, 8(3), 624–636.
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Badran, B. W., Dowdle, L. T., Mithoefer, O. J., Labate, N. T., Coatsworth, J., Brown, J. C., ... & George, M. S. (2018). Neurophysiologic effects of transcutaneous auricular vagus nerve stimulation (taVNS). Brain Stimulation, 11(3), 492-500.
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Goyal, M., Goyal, K., Patnaik, A., Mahapatra, A. K., & Singh, J. P. (2020). Non-invasive Vagus Nerve Stimulation for the Management of Epilepsy. Frontiers in Neurology, 11, 578965.
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Yuan, H., & Silberstein, S. D. (2016). Vagus Nerve and Vagus Nerve Stimulation, a Comprehensive Review: Part I. Headache, 56(1), 71–78.