Vagus nerve stimulation: therapy, gadget or social-media myth?

On Instagram and TikTok the vagus nerve has become a cure-all: face in ice water, a bit of humming or gargling, and stress, inflammation and poor sleep are supposed to melt away. Meanwhile, implanted vagus stimulators have been approved for almost 30 years, and ear clips promise to "regulate your nervous system". These are three very different things.

What the vagus nerve does

The vagus, the tenth cranial nerve, runs from the brainstem through the neck to the heart, lungs and gut. It is the main nerve of the parasympathetic system, which governs rest and digestion and slows the heartbeat. Most of its fibres carry signals from the organs to the brain, which is why stimulating it in the neck can influence brain function.

The scientific basis for today's anti-inflammatory claims was laid in 2002 by the immunologist Kevin Tracey with the concept of the "inflammatory reflex": through nerve signals, the vagus can damp the release of pro-inflammatory messengers, much as the nervous system regulates heart rate. This is solid basic science, largely from animal studies. Whether it works as a treatment in humans must be shown disease by disease; for wellness gadgets it has not been.

1. Implanted stimulation: a real, approved therapy

In classic vagus nerve stimulation (VNS), a pacemaker-like device is placed surgically under the skin below the left collarbone, with an electrode wrapped around the vagus nerve in the neck.

• Epilepsy: The US Food and Drug Administration (FDA) approved the system for epilepsy in July 1997. A Cochrane review (2022; 5 randomised trials, 439 participants) found that high-level stimulation was about 1.7 times as likely as low-level stimulation to halve seizure frequency (risk ratio 1.73; moderate certainty). Note: the comparison was high versus low stimulation, not versus none. VNS is an option when drugs fail and surgery is not possible; it is not a cure.
• Depression: Since July 2005, VNS has been US-approved as add-on treatment for chronic or recurrent depression after at least four failed adequate treatments. The large RECOVER trial (493 randomised patients with markedly treatment-resistant depression), however, missed its primary endpoint: after one year, symptom scores did not differ significantly between active and inactive stimulation. Later analyses report benefits on secondary measures, but these are post-hoc or uncontrolled analyses of a manufacturer-funded trial.
• Arm function after stroke: In VNS-REHAB (Lancet 2021; 108 people with moderate to severe arm weakness at least nine months after ischaemic stroke), stimulation was paired with physiotherapy movements. Arm function (Fugl-Meyer scale) improved by 5.0 points versus 2.4 with sham stimulation. At 90 days, 47% versus 24% had a clinically meaningful improvement, about 23 more people per 100. FDA approval followed in August 2021.
• Rheumatoid arthritis: In July 2025 the first implantable vagus stimulator for rheumatoid arthritis was approved in the US, for adults not helped by, or intolerant of, biologics or similar advanced drugs. In the sham-controlled RESET-RA trial (242 participants), 35.2% versus 24.2% achieved at least a 20% improvement (ACR20) at three months, about 11 more per 100. A modest effect, but the first clinical evidence that the inflammatory reflex can be used therapeutically.

Side effects: Hoarseness, voice change, cough and shortness of breath; hoarseness and breathlessness were more frequent with high-level stimulation. Add the risks of surgery: in VNS-REHAB one patient developed vocal cord paralysis.

2. Stimulation from outside: tVNS at the ear and neck

Transcutaneous VNS (tVNS) stimulates through the skin: at the neck with a handheld device, or at the ear, where a skin branch of the vagus runs.

A handheld neck device has been cleared in the US since 2017 for the acute treatment of episodic cluster headache, since 2018 for the acute treatment of migraine, and since late 2018 as an add-on to prevent cluster headache. In the sham-controlled PRESTO trial (243 people with migraine), 12.7% versus 4.2% were pain-free at 30 minutes; at 120 minutes the difference (30.4% versus 19.7%) was not statistically significant. The cluster-headache prevention trial was open-label, without a sham.

Ear stimulation rests on thinner evidence. A 2021 systematic review of 41 randomised trials rated most at high or some risk of bias and graded the evidence for every single indication as "low quality". It is even unclear how strongly ear stimulation activates the vagus at all: a meta-analysis of 17 studies in healthy people found strong evidence that it does not change vagally mediated heart-rate variability compared with sham.

Meanwhile, ear clips, neckbands and apps are sold for stress, sleep, "inflammation" or long COVID. Devices sold as wellness or lifestyle products have not demonstrated efficacy against any disease and are not approved to treat one. Trials of one device do not automatically apply to another with different electrodes, frequencies and currents.

3. "Vagus hacks": what is physiologically true

Cold water on the face triggers the diving reflex, which slows the heart via the vagus. In a small randomised study in young adults, 16 seconds of cold on the side of the neck slightly lowered heart rate and raised HRV. A meta-analysis of 223 studies shows that slow breathing increases vagally mediated HRV during practice, right after a session and after several weeks of training. In a meta-analysis of randomised trials (785 participants), breathing exercises reduced self-reported stress with small-to-medium effects, at moderate risk of bias.

But HRV is a marker, not a proven treatment target; nudging it up briefly is not treating disease. For high blood pressure, a meta-analysis of guided slow breathing found no reliable reduction (systolic −2.1 mmHg; confidence interval −12.7 to +8.4). See also home blood pressure measurement and stress and cortisol.

What this means for you

Questions to ask before buying a stimulation device

• Is it a medical device with an intended purpose for my condition, or a wellness gadget?
• Are there sham-controlled trials of exactly this device and these settings, published in a journal?
• What was the primary endpoint, was it met, and how big is the difference in absolute numbers?
• Do I have a pacemaker, another implant, a heart-rhythm disorder, or am I pregnant? Then check with a doctor first.

When to see a neurologist

If seizures continue despite medication, further options belong in an epilepsy centre, where surgery is assessed first and stimulation second. The same applies to cluster headache, hard-to-treat migraine or depression, and persistent arm weakness after stroke.

This article is general information and not individual medical advice. Decisions about tests and treatment belong in a conversation with your own physician.