AMA Style: When to Use Title Case vs. Sentence Case

The AMA Manual of Style (11th edition) is the standard reference for medical and scientific publication, used by JAMA and hundreds of biomedical journals. If you've only ever looked up "AMA title case rules," you've probably seen a single rule set: capitalize the first and last word, capitalize major words, lowercase short prepositions. That's accurate — but incomplete. It only describes half of how AMA actually formats a reference.

The part that trips up even experienced authors is this: AMA uses title case for journal names and full book titles, but sentence case for article titles inside a reference list. Both rules can appear in the same line of a bibliography.

What each rule actually looks like

Title case (for journal and book titles) follows the familiar major/minor-word pattern:

• Capitalize the first and last word.
• Capitalize all major words — nouns, verbs, adjectives, adverbs, pronouns.
• Lowercase articles, coordinating conjunctions, and prepositions of three letters or fewer.
• Capitalize prepositions of four letters or more.
• Capitalize the word after a colon.

Sentence case (for article titles in reference lists) is much simpler:

• Capitalize only the first word of the title.
• Capitalize the first word after a colon.
• Capitalize proper nouns wherever they appear.
• Everything else stays lowercase.

Seeing both rules in the same reference

Here's where it becomes concrete. A typical AMA-style journal reference looks like this:

Chen L, Patel R, Osei K. Effect of vitamin D supplementation on bone density in postmenopausal women: a randomized trial. Journal of Clinical Endocrinology. 2026;45(3):112-120.

Look closely at the two title-like elements in that reference:

• The article title — "Effect of vitamin D supplementation on bone density in postmenopausal women: a randomized trial" — is in sentence case. Only "Effect" (first word) and "D" (part of a proper noun, Vitamin D) are capitalized, along with "a" after the colon by the after-colon rule. "Bone," "density," "postmenopausal," and "randomized" all stay lowercase, even though they're clearly meaningful words.
• The journal name — "Journal of Clinical Endocrinology" — is in title case, right next to the sentence-cased article title. "Of" stays lowercase (three letters or fewer), but "Journal," "Clinical," and "Endocrinology" are all capitalized.

If you ran the entire reference through a single title-case pass, you'd incorrectly capitalize "Supplementation," "Density," "Postmenopausal," and "Women" in the article title — a mistake that's easy to make and genuinely common in submitted manuscripts.

Why AMA splits the rule this way

The logic mirrors a broader pattern used by APA and several other academic style guides: reference lists are optimized for scanning consistency across dozens or hundreds of entries, so article titles — which vary enormously in length and content — are flattened to sentence case to keep the list visually calm. Journal and book titles, by contrast, are proper names of publications, and proper names get title case regardless of context, the same way you'd capitalize a company name or a person's name.

Once you see it this way, the split stops feeling arbitrary: sentence case is for descriptive content (what the article is about), and title case is for the name of the thing that published it.

Section headings: a separate question entirely

A related but distinct question is how to capitalize in-text section headings — Methods, Results, Discussion, and similar labels within the body of a manuscript. The AMA Manual itself doesn't impose one universal rule for every heading level across every possible document type. In practice, many journals that otherwise follow AMA reference style use sentence case for section headings as part of their own house style, independent of the reference-list rule described above. If you're preparing a manuscript for a specific journal, check that journal's author guidelines rather than assuming the reference-list rule extends to your section headings automatically.

A simple decision rule

When you're not sure which case to use, ask what you're formatting:

Try it yourself

For journal and book titles, our AMA title case converter applies the three-letter preposition cutoff automatically. For article titles headed into a reference list, switch to the sentence case converter instead — it capitalizes only the first word, the word after a colon, and any proper nouns it recognizes, which is exactly what a reference-list article title needs.

Sources

This article summarizes public guidance from the AMA Manual of Style, 11th edition.

• AMA Manual of Style Online — official reference, Oxford University Press / American Medical Association