Low-intensity transcranial electric stimulation: ESBS/IFCN safety, ethics and regulation guidelines

• Updated (2017–2025) guidelines for low-intensity tES (tDCS, tACS, tRNS) cover safety, ethical, legal, regulatory and application aspects.¹
• The update is endorsed by the European Society for Brain Stimulation (ESBS) and the International Federation for Clinical Neurophysiology (IFCN) and supports trial design and regulatory positioning.^{1 1}

Weekly enrichment (2026-07-20)

• Across more than 300,000 tES sessions in healthy individuals, patients with neuropsychiatric conditions, and other clinical populations, no tES-related serious adverse events (AEs) were reported; moderate AEs are rare and limited to a small range of specific applications.^{2 3}
• Mild AEs (transient localized tingling or burning, headache, fatigue) are common but occur at rates comparable to placebo/sham stimulation, and AE frequency, magnitude, and type were similar across vulnerable groups including children, the elderly, and pregnant women.^{2 4}
• Safety is well-established for both bipolar and multichannel tES applied up to 4 mA and up to 60 min per day; higher intensities or longer durations may also be safe but the supporting number of studies is low.^{2 5}
• The guideline formally defines low-intensity tES as total current ≤4 mA (for AC waveforms ≤4 mA peak-to-peak), total duration up to 60 min per session, electrode sizes between 1 and 100 cm², and montages using 2–9 electrodes.⁵
• The update spans tDCS, oscillatory tDCS (otDCS), tACS, tRNS, transcranial temporal interference stimulation (tTIS), and their combinations or variations.^{2 3}
• Combined interventions co-applying tES with EEG, TMS, or neuroimaging did not show increased safety risks.^{2 4}
• The guideline was produced by expert consensus (multiple questionnaire rounds and voting, with results discussed at a meeting in Munich), organized by the IFCN Brain Stimulation Special Interest Group and the European Society for Brain Stimulation, both of which endorsed it.^{3 5}
• Home-based tES with remote supervision is growing rapidly, enabling greater access and repeated, sustained dosing paradigms; the panel recommends screening and AE questionnaires in future controlled studies, especially when extending stimulation parameters beyond current bounds.^{2 5}

Footnotes

1. https://www.sciencedirect.com/science/article/pii/S138824572501288X?dgcid=rss_sd_all ↩ ↩² ↩³

2. https://doi.org/10.1016/j.clinph.2025.2111436 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

3. https://pmc.ncbi.nlm.nih.gov/articles/PMC7618810/ ↩ ↩² ↩³

4. https://pubmed.ncbi.nlm.nih.gov/41622107/ ↩ ↩²

5. https://www.ifcn.info/UserFiles/file/CLINPH-S-25-01153_Targeted-Safety-Guidelines-update-Oct-2025.pdf ↩ ↩² ↩³ ↩⁴