ICMJE Guidelines 2026: How to Format a Medical Manuscript

In short: ICMJE guidelines (updated January 2026) require original research to use the IMRaD structure, a complete title page, a structured abstract, all four authorship criteria, full conflict-of-interest disclosures, prospective clinical trial registration, and NLM-style references. The 2026 update also adds a standalone section on artificial intelligence and a new rule on author access to underlying data. The full section-by-section checklist is below.

For any researcher submitting to a medical journal, ICMJE compliance is not optional. More than 5,500 biomedical journals worldwide require authors to follow the International Committee of Medical Journal Editors recommendations, including NEJM, JAMA, The Lancet, BMJ, Annals of Internal Medicine, and most major specialty journals. Furthermore, journals that do not formally require ICMJE compliance still use it as the default framework for evaluating manuscript quality, ethics, and reporting standards.

If editors have returned your paper citing “non-compliance with ICMJE guidelines,” “incomplete author contributions,” “missing trial registration,” or “inadequate disclosures,” you have already experienced how strict these requirements are. Editors check ICMJE compliance early, often before sending a paper for peer review, and gaps in formatting or ethics reporting frequently lead to immediate rejection or revision requests.

This guide explains how to format a medical manuscript according to current ICMJE guidelines, updated to reflect the January 2026 version of the recommendations. It covers what changed in 2026, the IMRAD structure, title page requirements, abstract format, authorship criteria, trial registration, disclosures, and references. By the end, you will have a clear, actionable framework you can apply to any submission to an ICMJE-compliant journal.

What ICMJE Is and Why It Matters

The International Committee of Medical Journal Editors (ICMJE) is a working group of editors from leading biomedical journals. The group has published guidance for medical manuscript preparation since 1979, originally under the title “Uniform Requirements for Manuscripts Submitted to Biomedical Journals.” In 2013, ICMJE renamed the document to “Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals” to reflect its expanded scope.

ICMJE released the most recent update in January 2026. Authors submitting to any ICMJE-compliant journal should follow this current version.

The recommendations cover three broad areas: ethics (authorship, conflict of interest, peer review responsibilities), reporting standards (IMRAD structure, abstract format, references), and publication practices (overlapping submissions, corrections, retractions). Furthermore, ICMJE coordinates closely with the EQUATOR Network on study-design-specific reporting guidelines such as CONSORT, STROBE, and PRISMA.

What Changed in the January 2026 Update

The January 2026 revision is now the current version of the ICMJE Recommendations. If you have not submitted since it took effect, apply these changes now — major publishers have already begun updating their submission systems to reflect them.

• A new standalone section on artificial intelligence (Section V). ICMJE moved its AI guidance out from under the authorship rules into its own dedicated section and expanded it. AI tools still cannot be listed as authors, and any use of AI in drafting or preparing a manuscript must be disclosed.
• A new provision on author access to underlying data. Authors are now expected to have sufficient access to the study’s underlying data to take responsibility for the integrity and accuracy of the work. This is aimed particularly at industry- or sponsor-funded research, where data access has historically been restricted.
• Reaffirmed clinical trial registration timing. Trials should be registered in a WHO- or ICMJE-compliant registry at or before the time of first participant consent, and editors are encouraged to verify that registration is complete, accurate, and prospective.
• Refined correction terminology and stronger safeguards against sponsor influence over data access and analysis.

ICMJE publishes an annotated PDF marking exactly where the January 2026 changes were made; you can review it on the official ICMJE announcement page.

The Overall Structure: IMRAD

ICMJE recommends the IMRAD structure for original research manuscripts:

• Introduction
• Methods
• Results
• And
• Discussion

ICMJE describes IMRAD not as an arbitrary publishing convention but as a reflection of how scientific research actually unfolds. Other manuscript types may follow different structures: case reports, narrative reviews, editorials, and meta-analyses use formats appropriate to their content.

Within each IMRAD section, subheadings often improve organization. Furthermore, electronic submission allows for supplementary materials such as datasets, additional figures, and protocols that support the main text without crowding it.

The Title Page

The title page is the first item editors review, and ICMJE specifies several required elements.

Required components of the title page:

1. Article title. Concise and informative. Titles appear in indexing and citation databases, so include the major concepts that allow the paper to be found in a literature search.
2. Authors’ names and institutional affiliations. Use the form each journal requires (some prefer first name + last name, others initials + last name).
3. Department and institution attribution. State the department, institution, and city where the work was performed.
4. Disclaimers, if any. For example, statements that views expressed do not reflect those of an institution or funder.
5. Corresponding author. Full contact information, including telephone number and email address. ICMJE encourages including ORCID identifiers for all authors.
6. Source of support. Grants, equipment, drugs, or financial support provided by sponsors.
7. Short running head. A condensed title for use as a page header, typically under 40 characters.
8. Word counts. Word count for the main text (excluding abstract, references, tables, figure legends) and a separate count for the abstract. These help editors check space limits.
9. Number of figures and tables. Required by most electronic submission systems so editorial staff can confirm completeness.
10. Disclosure of relationships and activities. Each author must disclose conflicts of interest. ICMJE provides a uniform disclosure form used by its member journals.

A missing or incomplete title page is one of the fastest reasons for desk-stage delays or rejections at ICMJE-compliant journals.

The Abstract

ICMJE specifies that the abstract should provide the context, the purpose of the study, the basic procedures, the main findings, the principal conclusions, and the funding sources.

Structured abstract format (most ICMJE journals):

• Background: Context or rationale for the study.
• Objective: Specific purpose or hypothesis tested.
• Methods: Study design, setting, participants, interventions, main outcome measures.
• Results: Main findings with effect sizes and statistical significance.
• Conclusions: Principal conclusions linked to the study aim.

Other required elements:

• Clinical trial registration number at the end of the abstract if the study is a clinical trial.
• Trial acronyms with their registration number on first use.
• Data set identifiers if data have been deposited in a public repository or used in a secondary analysis.

Word limits vary by journal but typically fall between 250 and 300 words. Always check the target journal’s specific abstract requirements.

Detailed Section-by-Section Requirements

Introduction

ICMJE requires the Introduction to provide context or background, state the specific purpose or research objective, and briefly describe the rationale for the study. Avoid extensive reviews of the literature (Discussion or a separate review article should handle that). Cite only directly pertinent references and do not include data or conclusions from the work being reported.

Methods

The Methods section must enable other researchers to reproduce the study. Required elements include:

• Selection and description of participants. Eligibility criteria, recruitment, and source population.
• Technical information. Procedures, equipment (with manufacturer name and location), and pharmaceuticals (with generic names, doses, routes of administration).
• Statistics. Statistical methods used, software with version, and how missing data were handled.
• Sample size justification. Power analysis or, for qualitative studies, saturation reasoning.
• Ethical approval. Statement that the study was approved by an institutional review board or ethics committee, with the approval reference number. Studies on human subjects must conform to the Declaration of Helsinki.
• Consent statements. Documentation that informed consent was obtained.

Furthermore, randomized trials should follow the CONSORT reporting guideline, observational studies should follow STROBE, and systematic reviews should follow PRISMA. ICMJE explicitly endorses these EQUATOR Network reporting guidelines.

Results

Present results in logical sequence in the text, tables, and figures. Do not repeat data shown in tables and figures within the text; instead, emphasize the most important observations. Report numbers, effect sizes, and statistical significance, ideally with confidence intervals.

Discussion

The Discussion should focus on what the new findings mean and what their implications are. Begin with a brief summary of the main findings, then explore mechanisms, compare findings to prior research, acknowledge limitations, and end with implications for practice or future research. Avoid repeating in detail what has been said in Results.

ICMJE specifically asks authors to distinguish new and important aspects of the study from observations already in the literature.

ICMJE Authorship Criteria (2026)

The ICMJE requires all four of the following criteria to be met for someone to qualify as an author. Meeting only some of them means a contributor should be acknowledged, not listed as an author.

1. Substantial contributions to the conception or design of the work, or the acquisition, analysis, or interpretation of data.
2. Drafting the work or reviewing it critically for important intellectual content.
3. Final approval of the version to be published.
4. Accountability for all aspects of the work, including ensuring that questions related to accuracy or integrity are appropriately investigated.

If a contributor meets fewer than all four criteria, the team should acknowledge them rather than list them as an author. Furthermore, following the January 2026 update, guidance on artificial intelligence now sits in its own standalone section: AI tools (such as ChatGPT or other large language models) cannot serve as authors, since they cannot take responsibility or provide approval, and any AI assistance must be disclosed.

The corresponding author takes primary responsibility for communication with the journal during submission, peer review, and publication.

Conflict of Interest Disclosures

Every author must disclose all relationships and activities that might be perceived as potential conflicts of interest. ICMJE provides a uniform disclosure form that most member journals accept.

Disclosures should cover:

• Financial relationships (grants, consultancies, stock ownership, paid speaking, expert testimony)
• Personal relationships that could influence the work
• Intellectual property and patents
• Any other relationship that a reasonable reader might consider relevant

Missing or incomplete disclosures are one of the most common reasons for post-acceptance corrections, retractions, or formal investigations. Therefore, disclose more rather than less when in doubt.

Trial Registration

ICMJE-compliant journals require prospective registration of clinical trials before participant enrollment. Registration must be in a registry that meets ICMJE criteria, such as ClinicalTrials.gov, the ISRCTN registry, or the WHO International Clinical Trials Registry Platform. Following the January 2026 update, editors are encouraged to verify that registration was completed at or before the time of first participant consent.

The trial registration number must appear at the end of the abstract and on first mention of the trial in the main text.

Furthermore, unregistered or retrospectively registered trials are typically not accepted by ICMJE journals. This requirement has eliminated a significant proportion of selective outcome reporting in clinical research.

References

ICMJE recommends following the citation style used by the U.S. National Library of Medicine (NLM), as documented in the NLM Citing Medicine guide.

Key reference rules:

• Number references in order of appearance in the text.
• Use Arabic numerals in superscript or parentheses, as specified by the journal.
• For journal articles with up to six authors, list all six. For more than six, list the first six followed by “et al.”
• Include the DOI for every reference where available.
• Cite only verified, accessed sources. Avoid using abstracts as references when possible.
• Cite personal communications in the text, not in the reference list, with written permission from the source.

ICMJE explicitly cautions against using citation generators without verification, since errors in generated references are common and time-consuming to fix during revision.

Tables, Figures, and Units of Measurement

Tables:

• Numbered sequentially in the order first cited in the text.
• Each table on a separate page with a short title.
• Use footnotes to explain non-standard abbreviations.
• Do not duplicate data shown in figures.

Figures:

• Numbered sequentially in the order first cited.
• Submitted in formats specified by the journal (typically TIFF, JPEG, or EPS).
• Include a brief, self-contained legend for each figure.
• Photomicrographs require an internal scale marker; symbols, arrows, and letters should contrast with the background.
• Identifiable patient information requires written informed consent.

Units of measurement:

• Use the International System of Units (SI) for measurements.
• For drug concentrations, also report alternative units where the SI form is uncommon in clinical practice.

Ethical Approvals and Patient Consent

ICMJE requires explicit statements in the Methods section confirming:

• Approval by an institutional review board, ethics committee, or equivalent body, with the approval reference number.
• Informed consent from all participants (or appropriate documentation for waivers).
• For animal studies, compliance with institutional and national guidelines for the care and use of laboratory animals.
• For studies involving identifiable patients in case reports or photographs, written consent from the patient or legal guardian.

Furthermore, ICMJE requires authors to confirm that the work conforms to the Declaration of Helsinki (for human research) and to recognized animal welfare standards.

Common ICMJE Compliance Mistakes

After preparing thousands of manuscripts for ICMJE-compliant journals, the same compliance issues come up repeatedly:

1. Missing trial registration number in the abstract or first mention.
2. Incomplete authorship contributions. Not every co-author has documented all four ICMJE criteria.
3. Vague conflict of interest disclosures. “None” is acceptable only if accurate; partial disclosures are not.
4. Missing ethics approval reference number. A statement that “ethics approval was obtained” is insufficient; the reference number is required.
5. References not in NLM format. Citation generators often produce incorrect formatting.
6. Non-SI units of measurement without conversion.
7. Duplicate publication concerns not addressed in the cover letter, where prior conference abstracts or preprints exist.
8. Reporting guideline non-compliance. CONSORT, STROBE, or PRISMA checklists not completed where required.
9. AI tool use not disclosed. Following the 2026 update, any use of large language models or AI-assisted drafting must be acknowledged.
10. Missing word counts for main text and abstract on the title page.

Fixing these issues before submission can substantially reduce desk rejection risk.

A Pre-Submission ICMJE Checklist

Before submitting any manuscript to an ICMJE-compliant medical journal, run through this checklist:

• Title page includes all required elements (title, authors, affiliations, corresponding author, disclosures, word counts)?
• Abstract follows structured format with all required elements?
• Trial registration number included where applicable, with registration at or before first participant consent?
• IMRAD structure used for original research?
• All four ICMJE authorship criteria documented for each author?
• AI tool use disclosed if any was used?
• Author access to underlying data confirmed (especially for sponsor-funded studies)?
• Ethics approval reference number stated in Methods?
• Informed consent statement included?
• Conflict of interest disclosures complete for every author?
• CONSORT, STROBE, or PRISMA checklist completed if applicable?
• References formatted in NLM style with DOIs?
• SI units used throughout, with conversions where helpful?
• Figures and tables numbered, captioned, and not duplicated?
• Cover letter addresses any prior conference or preprint publication?
• Compliance with the January 2026 ICMJE Recommendations confirmed?

If you can tick all of these, your manuscript is in line with current ICMJE expectations.

When Expert Editing Helps with ICMJE Compliance

ICMJE compliance combines formatting, ethics reporting, and discipline-specific reporting standards. Many manuscript revisions and rejections trace back to compliance gaps that a trained medical editor can identify and fix in a single review cycle.

The most useful service for ICMJE-related formatting and structure is thesis formatting, where our editors prepare your manuscript according to ICMJE requirements and your target journal’s specific guidelines, including reference style, structured abstract, and figure or table conventions. For comprehensive structural and language review, Substantive Editing addresses formatting alongside section coherence, reporting standard compliance, and overall manuscript readiness. If you want either service applied to your medical manuscript, contact our team at ManuscriptLab.

For the authoritative source on all current requirements, the official ICMJE Recommendations page provides the full document, updated January 2026.

Frequently Asked Questions

What is the ICMJE IMRaD structure? IMRaD stands for Introduction, Methods, Results, and Discussion — the structure ICMJE recommends for original research manuscripts, because it mirrors how a study is actually conducted.

When was the last ICMJE update? The most recent update was January 2026. It added a standalone section on artificial intelligence and a new provision on author access to underlying data. Always confirm the current version on the official ICMJE website before submitting.

Are ICMJE guidelines mandatory? More than 5,500 biomedical journals follow ICMJE recommendations. While not legally mandatory, compliance is required by virtually every major medical journal and strongly expected by the rest.

Can I list AI tools like ChatGPT as authors? No. ICMJE explicitly states that AI tools cannot be authors because they cannot take responsibility for the work or provide final approval. Following the January 2026 update, AI use should be disclosed, and AI guidance now sits in its own section of the recommendations.

What if my coauthor only contributed to data collection? Data collection alone does not meet ICMJE authorship criteria. The contributor should be acknowledged in the Acknowledgements section instead.

Do case reports follow IMRAD? Not strictly. Case reports use a different structure: introduction, case presentation, discussion, and conclusion. However, ethics, consent, and disclosure requirements still apply.

Is trial registration required for non-clinical trials? ICMJE strongly encourages registration for any prospective study involving human participants. Mandatory registration applies specifically to clinical trials as defined by ICMJE.

Conclusion

ICMJE guidelines look extensive, but they exist to make medical research more reproducible, transparent, and trustworthy. Compliance protects both authors and journals from issues that often surface after publication.

In summary, follow IMRAD for original research. Build a complete title page with all required elements. Use the structured abstract format. Confirm all four ICMJE authorship criteria for every author. Disclose conflicts and AI tool use. Register clinical trials prospectively, and confirm your access to the underlying data. Finally, run the pre-submission checklist before you upload anything to the journal portal.

Do those things and your manuscript will meet the standard that most leading medical journals expect.