Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines (2017–2025: An update) – endorsed by the European Society for Brain Stimulation (ESBS) and by the International Federation for Clinical Neurophysiology (IFCN)
Andrea Antal, Jovana Bjekić, Ana Ganho-Ávila, Ivan Alekseichuk, Sara Assecondi, Til Ole Bergmann, Marom Bikson, Jérôme Brunelin, André R. Brunoni, Leigh Charvet, Robert Chen, Roi Cohen Kadosh, Lukas Diedrich, Giordano D’Urso, Roberta Ferrucci, Saša R. Filipović, Paul B. Fitzgerald, Agnes Flöel, Flavio Frӧhlich, Mark S. George, Roy H. Hamilton, Jens Haueisen, Mark Hallett, Christoph S. Herrmann, Friedhelm C. Hummel, Shapour Jaberzadeh, B. Langguth, Michal Lavidor, Jean‐Pascal Lefaucheur, Carlo Miniussi, Vera Moliadze, Mika Nikander, Stevan Nikolin, Michael A. Nitsche, Alexander Opitz, Jacinta O’Shea, F. Padberg, Christian Plewnia, Alberto Priori, Perianen Ramasawmy, Laís B. Razza, Símone Rossi, John C. Rothwell, Maria Adele Rueger, Giulio Ruffini, Alexander T. Sack, Ricardo Salvador, Klaus Schellhorn, Teresa Schuhmann, Y. Shirota, Hartwig R. Siebner, Axel Thielscher, Yoshikazu Ugawa, Susanne Uusitalo, Anna Wexler, Walter Paulus, Marie–Anne Vanderhasselt, Vincent Van Waes, Maximilian J. Wessel, M. Wischnewski, Chris Baeken, Ulf Ziemann
Abstract
This guideline summarizes updated safety data (2017-2025) and provides expert recommendations on the use of low intensity transcranial electrical stimulation (tES) in humans. tES encompasses several techniques including transcranial direct current stimulation (tDCS), oscillatory transcranial direct current stimulation (otDCS), transcranial alternating current stimulation (tACS), transcranial random noise stimulation (tRNS), transcranial temporal interference stimulation (tTIS), and their combinations or variations. Across over 300,000 sessions involving healthy individuals, patients with neuropsychiatric conditions, and other clinical populations, no tES-related serious adverse events (AEs) have been reported. Moderate AEs are rare and limited to a small range of specific applications. Mild AEs are common and include transient symptoms such as localized sensations (e.g., tingling or burning), headaches, and fatigue. Similar mild AEs are also reported by individuals receiving placebo stimulation. The frequency, magnitude, and type of AEs are comparable across healthy, clinical, and vulnerable groups, including children, elderly, or pregnant women. Combined interventions (e.g., co-application with EEG, TMS, or neuroimaging) have not shown increased safety risks. Safety is well-established for both bipolar and multichannel tES when applied up to 4 mA and up to 60 min per day. Higher intensities and longer stimulation durations may also be safe. Nevertheless, the number of studies using intensities above 4 mA or stimulating longer than 60 min is low. Home-based use of treatments is growing rapidly, leveraging remote supervision to provide patients with greater access and enable repeated, sustained dosing paradigms. We recommend using screening and AE questionnaires in future controlled studies, in particular when planning to extend the stimulation parameters applied. We discuss recent regulatory and ethical issues.