Change in v1.2.2. The reference database promised in the Availability-of-data statement now exists and is cited by DOI: 10.5281/zenodo.22831175 (concept), registered on Zenodo as a supplement to this manuscript. It holds 175 records with a crosswalk column mapping each to its numbered reference here, a codebook, the search log, and the script that reproduces Section 5.2. One figure in Section 5.2 (the field in fat at 1 mA) is corrected from 38.5 to 38 mV/mm, so that all six figures are given to the two significant figures the section states it uses. No other scientific content, value, table, figure or reference changed. Change in v1.2.1 (file only). The Availability-of-data statement in v1.2 carried an unresolved placeholder, "[DOI to be added]". It is replaced with a statement of fact: the verified reference database will be deposited before submission and linked from this record, and no identifier is quoted for a deposit that does not yet exist. No scientific content, value, table, figure or reference changed between v1.2 and v1.2.1. Change in v1.2.1 (file only). The Availability-of-data statement in v1.2 carried an unresolved placeholder, "[DOI to be added]". It is replaced with a statement of fact: the verified reference database will be deposited before submission and linked from this record, and no identifier is quoted for a deposit that does not yet exist. No scientific content, value, table, figure or reference changed between v1.2 and v1.2.1. Preprint. Not peer reviewed. Not submitted to any journal.
Electrical quantities are set at the terminals of bioelectronic devices, yet tissue responds to quantities that are rarely reported: the electric field at the cell, current density, charge per phase and the time course of membrane polarisation. This narrative review assembles, from primary literature and systematic reviews, a framework linking voltage, current, frequency, waveform and charge to their biological counterparts. It covers membrane biophysics; measured electrical properties of human tissues; endogenous fields in development, regeneration and wound repair; electrophysiological measurement; and the transfer problem by which surface-applied current is attenuated and redistributed before reaching a target. It examines what frequency does and does not explain, benchmarks established electrotherapies against their best available evidence, cautions against cross-species inference, and proposes a minimum parameter reporting set and a ten-category scheme for classifying claims by evidential status.
Novelty has not been independently established for either proposed instrument. No formal prior-art or scoping search was performed; the related prior work (Peterchev et al. 2012 on transcranial dose reporting; TIDieR and the CONSORT extension for non-pharmacological treatments; SENIAM) is named in Section 9.1.
Version history — and why it matters
Version 1.2 (18 September 2026) is a substantial correction of version 1.1, which was graded RED by adversarial internal review and was not fit to circulate. The review found that seven findings unfavourable to surface-applied electrical stimulation had been removed from sources the manuscript otherwise relied on, and that all seven ran in the same direction — toward making the field in which the author has a commercial interest look better founded and safer than its sources say. The manuscript's numbers were accurate: 27 of 27 reference records checked were bibliographically clean. The defect was in selection, not transcription.
All seven are restored in v1.2, each at the point where its source is already cited:
The DepressionDC trial (Burkhardt et al., Lancet 2023) — the largest sham-controlled multicentre trial of transcranial direct-current stimulation in depression, which is null (MADRS difference 0.3, 95% CI −2.4 to 2.9) — had been omitted entirely.
EF-14's mild-to-moderate skin toxicity in 52% of the device group, omitted from a review whose own Table 4 makes skin-effect reporting mandatory.
The pressure-ulcer Cochrane review's reported harms, including limb amputation and death, and its two uncertain outcomes.
ELECT-TDCS's excess of skin redness, tinnitus and nervousness, and its confidence interval.
Faes's analysis of covariance showing the six soft-tissue resistivity means are not statistically distinguishable from one another.
Vöröslakos's conclusion that effective currents are higher than those used in conventional protocols.
Huang's qualifier that 0.8 V/m at 2 mA is the lower limit of effectiveness in animal studies.
A negative trial of tumour-treating fields in recurrent glioblastoma (EF-11) was also added, so that modality is not represented by its positive trial alone. Section 11 of the manuscript records that the omissions occurred, because deleting the evidence of a selection problem would repeat the problem.
Stated limitation on verification
Content verification — checking each quantitative value and each characterisation against its source — was performed at the level of the abstract, and at full text only where the full text was openly accessible. It was not performed against the full text of paywalled sources. Section 1.1 states this, and the manuscript carries an explicit pre-submission condition that the author read those sources in full text before any journal submission. This preprint is deposited with that condition outstanding and openly declared.
Competing interests
The author is the founder, Chief Executive Officer and Chief Technology Officer of Rohera Healthcare & Technology Pvt. Ltd., Pune, India, which develops and markets eMedica, a device combining electrical stimulation with other energy modalities and physiological sensing, and is the named inventor and holder of granted patents relating to it (US 12,226,183 B2; JP 7611901 B2; AU 2020346420 B2; CA 3150348 C; KR 10-2954775 B1; ZA 2022/04073 B), with further grants and pending applications in other jurisdictions.
This review is not neutral ground for its author. Sections 9 and 10 propose reporting requirements and research priorities for a device class that includes the author's own product. No data from that device are presented and no claim of efficacy for it is made anywhere in the review, but readers should weigh the recommendations accordingly. Section 9.3 classifies the review's own principal claims under its own evidence scheme.
Funding
This work received no external funding. It was funded by the author, through Rohera Healthcare & Technology Pvt. Ltd. Self-funding is declared here as a competing interest rather than as the absence of one: no external sponsor, grant reviewer or independent body reviewed, constrained or verified this work at any stage.
Use of AI-assisted tools
A large language model (Claude, Anthropic) was used to run and organise the literature searches, to check bibliographic details against PubMed and Crossref records, to check quoted values against source abstracts and openly accessible full texts, to draft the text, and to conduct the adversarial internal review described above. The author directed this work, reviewed and edited all content, and takes full responsibility for the manuscript. The tool is not an author and does not meet ICMJE authorship criteria.