AMA Citation Style Guide 2026: How to Cite in AMA 11th Edition (Medicine & Health)
Medical and health sciences writing demands precise, unambiguous attribution — and AMA citation style exists to deliver exactly that. The AMA Manual of Style: A Guide for Authors and Editors, now in its 11th edition (Oxford University Press, 2020), is the authoritative rulebook for medicine, nursing, pharmacy, public health, and the biomedical sciences. Its numbered superscript system keeps clinical prose clean while ensuring every claim is traceable to its source — a non-negotiable standard in a field where evidence quality has direct patient consequences.
Whether you are submitting to JAMA, writing a medical thesis, preparing a systematic review, or completing coursework in health sciences, this guide gives you the complete 2026 rules for AMA citation style — with worked examples for every source type you will realistically encounter. If you need to decide which citation style fits your discipline before diving in, see our guide on what citation style to use for your thesis.
AMA citation style uses superscript Arabic numerals for in-text citations, numbered in order of first appearance. The reference list mirrors that order (not alphabetical). For journals, cite all authors if 6 or fewer; use the first 3 followed by et al. for 7 or more. Superscripts go outside periods and commas but inside semicolons and colons. The authoritative source is the AMA Manual of Style, 11th edition (2020).
What Is AMA Citation Style?
AMA citation style is a documentary-note system developed by the American Medical Association for use across its journals, including JAMA, JAMA Internal Medicine, and JAMA Surgery. The system assigns each cited source a unique Arabic numeral on first citation; that numeral is embedded in the text as a superscript and repeated whenever the same source is cited again. The complete reference details appear in a numbered list at the end of the document.
AMA style is widely required or recommended across:
- Medical and health sciences theses and dissertations
- Submissions to AMA-affiliated journals
- Undergraduate and postgraduate coursework in medicine, nursing, and pharmacy
- Systematic reviews, clinical guidelines, and public health reports
- Grant applications in biomedical research
The 11th edition, published in 2020, introduced clarifications for citing electronic resources, preprints, and datasets — source types that did not exist or were rarely cited when earlier editions were written. It is the current standard and supersedes all previous editions.
AMA citation style rules for medical writing, produced by the Research Medical Library at UT MD Anderson Cancer Center. Source: Research Medical Library on YouTube.
In-Text Citations: Superscript Rules
The in-text component of AMA citation style is deceptively simple but has specific placement rules that differ subtly from other numbered systems such as Vancouver. Getting these right matters because most journal submission systems flag formatting inconsistencies automatically.
Core Placement Rule
Superscript numerals are placed outside (after) periods and commas, and inside (before) colons and semicolons. No space appears between the preceding text and the superscript. Examples:
| Situation | Correct placement | Example |
|---|---|---|
| End of sentence | After the period | …was associated with reduced mortality.3 |
| After a comma | After the comma | …in randomised trials,4 observational studies5… |
| Before a colon | Before the colon | …three outcomes6: mortality, morbidity, and function |
| Author named in text | Immediately after the name | Smith7 demonstrated that… |
Multiple Citations at One Point
When citing multiple sources at the same location, list the numerals in ascending order separated by commas (no spaces). Use an en dash to indicate a consecutive range:
- Non-consecutive: 2,4,7
- Consecutive range: 3-6
- Mixed: 2,4-6,9
Reusing a Citation Number
Once a source has been assigned a number, that number is used every time the source is cited again — regardless of how many pages later. Do not reassign a new number to a previously cited source. If page-specific information is required, include the page number in parentheses within the superscript: 3(p47).
Reference List: Formatting and Order
The reference list in AMA style carries the heading REFERENCES (all capitals, left-aligned). References are numbered in the order they first appear in the text — not alphabetically. Each reference begins with its number followed by a period. The list is single-spaced within each entry and double-spaced between entries.
Author Name Format
AMA author name rules are distinctive:
- Surnames precede initials: Smith AB, not Smith, Andrew B
- No periods between initials: Smith AB, not Smith A.B.
- No comma before “and” between the penultimate and final author
- Authors separated by commas
- Up to 6 authors: list all names
- 7 or more authors: list the first 3 names followed by et al. (roman type, not italicised)
AMA 11th Edition — Key Rules at a Glance
| In-text format | Superscript Arabic numerals (1) |
| Reference list order | Order of first appearance (not alphabetical) |
| Author initials | No periods: Smith AB (not Smith A.B.) |
| et al. threshold | 7+ authors → list first 3 + et al. |
| Journal names | Abbreviated per NLM Catalog, italicised |
| DOI format | doi:10.xxxx/xxxxx (no trailing period) |
| Publisher city | Not required (11th edition change) |
Citing Journal Articles
Journal articles are the most common source type in medical writing, so this format is worth memorising. The authoritative abbreviated journal titles come from the NLM Catalog (National Library of Medicine).
Standard Format
Author AA, Author BB, Author CC, et al. Title of article. Abbreviated Journal Name. Year;volume(issue):first page-last page. doi:10.xxxx/xxxxxxx
Worked Examples
Article with up to 6 authors (all listed):
Article with 7 or more authors (et al.):
Article with no DOI (use URL instead):
Journal Abbreviations
Journal titles are always abbreviated using NLM standard abbreviations and set in italics. If the NLM Catalog does not list an abbreviation for a journal, spell out the full title in italics. Do not invent abbreviations.
Citing Books and Book Chapters
Entire Book
Author(s) or Editor(s), ed/eds. Title of Book. Edition (if not 1st). Publisher Name; Year of publication.
Example — book with authors:
Example — edited book:
Book Chapter
Chapter Author(s). Title of chapter. In: Editor(s), ed/eds. Title of Book. Edition (if not 1st). Publisher Name; Year:first page-last page.
Example:
Key points for books: No edition statement is needed for first editions. The publisher name is given without its city of publication — a deliberate simplification in the 11th edition that removes the city/state field required by earlier editions.
Citing Websites and Online Resources
Websites, institutional pages, and online reports are common in health sciences writing. The 11th edition requires an accessed date for all online sources, because web content can change or disappear.
Standard Format
Author(s) or Organisation. Title of page. Name of Website. Published [Month Day, Year]. Updated [Month Day, Year]. Accessed [Month Day, Year]. URL
Example — government/institutional page:
Example — no individual author:
If no publication date is available, omit the “Published” field. The URL should be placed at the end with no trailing period after it, as a period could be misread as part of the address.
Citing Preprints
Preprints — manuscripts posted to servers such as medRxiv and bioRxiv before peer review — are increasingly cited in health sciences literature, particularly during rapidly evolving public health events. The AMA 11th edition treats preprints as citable archival documents.
Format
Author AA, Author BB, Author CC, et al. Title of preprint. Preprint Server. Preprint posted online [Month Day, Year]. doi:10.xxxx/xxxxxxx
Example — medRxiv preprint:
Example — bioRxiv preprint:
AMA vs Vancouver: Key Differences
Both AMA and Vancouver citation style belong to the numbered-superscript family, and students often confuse the two. They share the same core logic — numerals assigned in order of appearance, reference list in numerical order — but differ in meaningful formatting details. The table below clarifies the most practically important distinctions.
| Feature | AMA (11th ed) | Vancouver (ICMJE) |
|---|---|---|
| Primary standard body | American Medical Association | ICMJE (International Committee of Medical Journal Editors) |
| Primary geographic use | United States | International |
| et al. threshold | ≥7 authors → list first 3 + et al. | ≥7 authors → list first 6 + et al. (ICMJE recommendation) |
| Author initials | No periods: Smith AB | No periods: Smith AB (same) |
| Superscript vs brackets | Superscript numerals | Superscript or bracketed numerals [1] (journal-dependent) |
| Publisher city | Not required (11th ed) | Place of publication included |
| DOI format | doi:10.xxxx (no trailing period) | https://doi.org/10.xxxx or doi:10.xxxx |
The practical consequence is that if your institution or journal specifies “Vancouver style,” you should not default to AMA rules, and vice versa. Always check the specific Instructions for Authors or your department’s style sheet. For a full comparison of author-date and numbered systems, the APA vs MLA vs Chicago comparison guide offers useful broader context.
Common AMA Citation Mistakes
Even experienced writers make consistent errors in AMA style. The following are the most frequently flagged issues in manuscript submissions and student assignments:
1. Alphabetising the Reference List
The reference list must follow the order of first citation in the text — not alphabetical order. Alphabetising is an APA/Harvard habit that carries over inappropriately into numbered-citation work. Number 1 is the source cited first in your paper, full stop.
2. Placing the Superscript Inside Periods and Commas
This is the most common punctuation error. The AMA rule is the opposite of what many students expect: superscripts go after the period or comma, not before. Check every end-of-sentence citation in your document.
3. Confusing the et al. Threshold
AMA triggers et al. at 7 or more authors, listing only the first 3. Vancouver’s ICMJE recommendation lists the first 6 before truncating. Using the wrong threshold is a common error when switching between styles.
4. Using Unabbreviated Journal Titles
AMA requires abbreviated journal names from the NLM Catalog. Writing Journal of the American Medical Association instead of JAMA, or The New England Journal of Medicine instead of N Engl J Med, is incorrect. When in doubt, search the NLM journal abbreviation catalog.
5. Omitting the DOI
If an article has a DOI, include it. The 11th edition explicitly states that when a DOI is available it should always be provided, formatted as doi:10.xxxx/xxxxx with no trailing period. Omitting the DOI when it exists is a formatting error.
6. Adding Periods Between Initials
AMA uses Smith AB, not Smith A.B. Adding periods is one of the small errors that signals unfamiliarity with the style to journal editors and examiners.
7. Reassigning Numbers to Reused Sources
A source that has already been assigned the number 5 keeps that number throughout the document. Assigning it a new number (e.g., 12) when it appears again is incorrect. Software such as Zotero and EndNote can manage this automatically — see our guide on the best reference management tools for thesis writers.
Managing AMA Citations with Reference Software
Reference managers handle AMA numbering and formatting automatically, which eliminates the renumbering problem entirely. Both Zotero and EndNote carry the AMA 11th edition style — download the Zotero CSL style file from the Zotero style repository. When you add or remove a citation, the software renumbers all subsequent citations instantly. For high-stakes medical writing, this is not optional — it is standard practice.
If you are writing a health sciences thesis and want a broader perspective on how to manage dozens or hundreds of references consistently across styles, our guide on Harvard referencing illustrates how author-date systems handle the same challenge — useful context if your thesis spans interdisciplinary work.
For guidance on citing AI-generated content in academic work — an increasingly common issue in health sciences education — see our article on how to cite AI-generated content in APA, MLA, and Harvard. Note that the AMA Manual of Style does not yet have a fully codified format for AI tool outputs; the current best practice is to follow the general principles for citing electronic sources while adding a clear disclosure statement.
Frequently Asked Questions
What is AMA citation style used for?
AMA citation style is used primarily in medicine, health sciences, nursing, pharmacy, and biomedical research. It is the house style of the Journal of the American Medical Association (JAMA) and hundreds of affiliated journals. It uses superscript Arabic numerals for in-text citations and a numbered reference list ordered by first appearance in the text.
How do superscript citations work in AMA style?
In AMA style, in-text citations are superscript Arabic numerals placed immediately after the relevant word or sentence. They go outside periods and commas but inside semicolons and colons. Numbers are assigned in the order the sources first appear in the text, and the same number is reused every time that source is cited again. No space appears between the preceding text and the superscript.
What is the et al. rule in AMA 11th edition?
In AMA 11th edition, if a work has up to 6 authors, list all of them. If there are 7 or more authors, list only the first 3 names followed by et al. (roman type, not italicised). Author names use initials only without periods between them: Smith AB, Jones CD, Brown EF, et al.
What is the difference between AMA and Vancouver citation styles?
Both systems use numbered superscript in-text citations with references ordered by first appearance. Key differences: (1) AMA’s et al. threshold is 7 or more authors (list first 3), while ICMJE/Vancouver recommends listing the first 6 before truncating; (2) AMA does not require the publisher’s city of publication in the 11th edition, while Vancouver traditionally does; (3) AMA is a US-specific standard produced by the American Medical Association; Vancouver (ICMJE) is the international standard; (4) Vancouver allows bracketed numerals [1] as an alternative to superscripts, while AMA specifies superscripts exclusively.
How do I cite a website in AMA style?
Format: Author(s) or Organisation. Title of page. Website Name. Published [Month Day, Year]. Updated [Month Day, Year]. Accessed [Month Day, Year]. URL. If no individual author is listed, begin with the organisation responsible for the content. Always include an accessed date, as web content can change or be removed.
How do I cite a preprint in AMA style?
Cite preprints similarly to journal articles, but replace the journal name with the preprint server name (e.g., medRxiv, bioRxiv) in italics, add “Preprint posted online [Month Day, Year]”, and include the DOI. Example: Smith AB, Jones CD, Brown EF, et al. Title of preprint. medRxiv. Preprint posted online January 15, 2024. doi:10.1101/XXXXXX. Always check whether the target journal permits citation of preprints.
Further Reading
- Vancouver Citation Style: Complete Guide 2026 — full reference guide to the ICMJE numbered system
- Harvard Referencing Guide 2026 — the author-date alternative used in many UK and Australian health programmes
- APA Citation Format Masterclass — 7th edition rules for psychology and social sciences
- Best Reference Management Tools for Thesis Writers 2026 — Zotero, Mendeley, and EndNote compared
- OSCOLA Referencing Guide 2026 — the legal citation system used in UK law schools and law journals
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