AI writing tools appear to have shaped most of December 2025’s biomedical papers. A preprint on arXiv puts the share at roughly nine in ten, and earlier tallies came in much lower.
The study, which has not yet been peer reviewed, looked at full texts in PubMed Central and judged whether large language models likely helped produce them. It puts the AI-assisted share at 77 percent for English-language papers published in 2025 and 52 percent for 2024, suggesting rapid year-over-year growth.
Those numbers dwarf previous estimates. A 2025 analysis by some of the same researchers, which examined abstracts only, put the rate at 13.5 percent for 2024. Looking beyond biomedicine, another 2026 analysis across all academic fields put the share of probably AI-influenced 2025 papers at 57 percent.
Scientists told Nature the finding raises fresh questions about research integrity and peer review. If most biomedical manuscripts now contain machine-generated passages, reviewers and editors face a new burden: distinguishing legitimate writing assistance from undisclosed AI use that could mask errors or fabrication.
The Nature news report notes the field lacks agreed standards for disclosing and detecting AI involvement in papers. Journals are responding unevenly, with some requiring authors to declare AI use and others still silent on the practice.
