SAN FRANCISCO — Transcutaneous vagus nerve stimulation (tVNS) has emerged as a promising tool for everything from anxiety to cognitive enhancement, but two new meta-analyses suggest the evidence is stronger for easing anxiety than boosting cognition.

In the first analysis, tVNS was associated with significantly reduced anxiety severity, although the overall magnitude of improvement was modest. In the second study, the noninvasive neuromodulation approach failed to improve working memory or inhibitory control in healthy adults.

The wellness industry’s claims that tVNS can enhance cognition often cite small studies or research in clinical or sleep-deprived populations, evidence that cannot be extrapolated to healthy adults, said Thaís Mendes, MD, lead investigator of both analyses.

“When you pool results across multiple trials, as we did, the apparent benefits of VNS for cognitive enhancement in individuals without neuropsychiatric disorders largely disappear,” said Mendes, general practitioner at Prefeitura de Belo Horizonte and researcher at the Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

Mendes said the findings do not rule out a cognitive benefit from tVNS but suggest that any such effects may be more apparent in individuals with cognitive impairment than in healthy adults.

The results of both studies were presented on May 18 at the American Psychiatric Association (APA) 2026 Annual Meeting.

Hype vs Evidence

Unlike implanted vagus nerve stimulators, tVNS delivers electrical stimulation through the skin via electrodes placed on the ear or neck and does not require surgery.

Research supports the use of tVNS in major depressive disorder, treatment-resistant depression, and migraine. However, tVNS is often marketed on social media as a remedy for a broad range of conditions despite limited supporting evidence.

Such claims center around tVNS as a “nervous system reset” shifting the body into a calm state. Based on this idea, the wellness industry markets these devices for myriad uses including stress reduction, cognitive enhancement, and sleep improvement.

To assess whether the evidence is keeping pace with the hype, the researchers conducted separate meta-analyses of tVNS for anxiety and cognitive enhancement.

The anxiety analysis included 1261 participants from 23 randomized controlled trials spanning a range of clinical populations, including individuals with HIV/AIDS, epilepsy, insomnia, COVID, and Parkinson’s disease.

Anxiety severity was assessed using validated scales, including the Hamilton Anxiety Rating Scale, Zung Self-Rating Anxiety Scale, and Hospital Anxiety and Depression Scale. A random-effects meta-analysis was conducted, and pooled effect size was estimated as standardized mean difference (SMD).

Overall, tVNS was associated with significantly reduced anxiety severity scores (SMD, -0.59; P < .0001). While the result was statistically significant, the absolute improvement was small and may not be clinically meaningful.

The investigators concluded that tVNS may be a promising, noninvasive approach for managing anxiety symptoms but emphasized that additional research is needed to determine optimal stimulation parameters and identify the patients most likely to benefit.

Limited Evidence of Cognitive Benefit

Despite the positive findings, Mendes said she would not consider tVNS a first-line treatment for anxiety.

“The patients who might reasonably consider it are those who have exhausted standard options or cannot tolerate medication. We need cleaner trials in primary anxiety disorder populations before making stronger recommendations.”

The cognitive enhancement analysis included 838 healthy adults from 19 trials. Working memory and inhibitory control were assessed using standardized cognitive tasks, including n-back or go/no-go tests.

The results of the study showed tVNS was not associated with significant improvement of working memory scores (SMD, 0.17; P = .3410) or inhibitory control (SMD, -0.06; P = .7020).

The investigators said reports of cognitive benefits from tVNS should be interpreted cautiously, noting that earlier studies often combined multiple executive functions into a single outcome measure.

“Our study treated working memory and inhibitory control, which are distinctive cognitive domains, as separate outcomes, allowing for a more precise picture of where effects may or may not exist. Neither showed a significant benefit,” she said.

Mendes said the findings point to a more promising role for tVNS in treating clinical conditions than in enhancing cognition among healthy individuals.

“My biggest takeaway is that tVNS holds more promise as a clinical treatment than as a cognitive enhancer for healthy people. The evidence base is growing for conditions like depression and drug-resistant epilepsy, and given how safe and noninvasive it is, that is where future research should concentrate,” Mendes said.

A Note of Caution

Charles Conway, MD, professor of psychiatry at Washington University in St. Louis, who was not involved in the research, said the findings support a cautious interpretation of claims that tVNS enhances cognition in healthy adults.

Among healthy individuals, the meta-analysis “pretty conclusively demonstrates that there is not a strong effect,” he said. “I think it definitely suggests caution in believing that transcutaneous vagus nerve stimulation can improve cognition in people with normal brain function.”

He said he was more impressed with the results of the anxiety meta-analysis, noting that the effect size was moderate and suggested a worthwhile avenue for further research.

However, he noted limitations of the anxiety analysis, including the fact that the studies enrolled patients with a broad range of underlying conditions, and that anxiety was seldom the primary diagnosis.

In addition, the absence of a standardized tVNS protocol resulted in considerable variation in stimulation parameters, treatment frequency, and session duration across studies.

Mendes reported having no relevant disclosures. Conway reported being the lead investigator on the RECOVER vagus nerve stimulation trial.