Most PMC articles come from peer-reviewed journals, but PMC is an archive and also includes clearly labeled preprints.
Confused by PubMed Central and peer review? You’re not alone. PubMed Central (PMC) is a free archive that hosts full-text biomedical and life-science literature. The peer evaluation usually happens before items land in PMC—at the journal. Some records in the archive are different, though, such as preprints and book chapters, which aren’t assessed the way journal research papers are. This guide shows what’s reviewed, what isn’t, and how to check each record.
What PMC Is (And Isn’t)
PMC is a full-text repository run by the U.S. National Library of Medicine. Publishers and authors deposit content for public access. That content includes final journal articles, author accepted manuscripts, and select non-journal material. The archive itself doesn’t run an editorial board that sends papers out for referee reports. Instead, PMC accepts content from venues that already did that job or from programs that bring early research into view, such as preprints.
Quick View: Content Types And Review Status
Use this table as a fast map. It lists common items you’ll see in PMC and where review takes place.
| Content Type In PMC | Where Review Happens | Typical Status In PMC |
|---|---|---|
| Final Journal Articles (Publisher PDF or XML) | Journal’s peer review before acceptance | Peer-reviewed research with journal branding |
| Author Accepted Manuscripts (via NIHMS) | Journal review completed; this is the accepted version | Peer-reviewed, not yet the typeset version |
| Preprints (NIH Preprint Pilot) | No journal review at this stage | Not peer-reviewed; flagged with clear notices |
| Book Chapters/Reports | Editorial or invited review varies by publisher | Review level varies; not standard journal refereeing |
Peer Review In PMC Articles: What That Means
When you open a research paper in the archive and see journal branding, that article reached PMC after a normal editorial process at the journal. The routes differ. Sometimes the publisher sends the final typeset file. Other times the author deposits the accepted manuscript through the NIH Manuscript Submission (NIHMS) system as part of a funder’s public-access policy. Either way, the peer commentary and revisions occur upstream at the journal, not inside PMC.
Author Accepted Manuscripts Are Reviewed
An accepted manuscript is the author’s final version after referee comments are addressed. It may lack the final typesetting and layout, yet the science matches what was approved. In PMC, you’ll often see these labeled with a PMCID and an embargo date if the publisher delays public release. That still reflects a vetted paper; it’s just not the formatted PDF from the publisher.
Preprints In PMC Are Not Reviewed
Preprints in PMC exist to surface early research funded by NIH. They carry bold banners that state the lack of peer review. The archive treats them as early communication, not settled findings. Many later proceed to journals and receive referee input, but until that happens, treat them as provisional.
PMC Versus PubMed: Why The Distinction Matters
PubMed is a massive citation index. PMC is a full-text archive. A PubMed record might point to a paper you can’t read for free, while a PMC record serves the full text. Readers sometimes assume everything in both places shares the same vetting. That’s close for journal literature, yet the presence of preprints in PMC changes the picture. Always check the record type and any banners on the page.
How To Verify Peer Review On A PMC Record
The safest way to read a record is to check a few signals. You can do this in under a minute:
- Scan The Banner: If you see a preprint label, treat it as not reviewed yet.
- Look For Journal Branding: Journal name, volume, issue, and DOI point to a completed publication.
- Check The Version Note: “Author Accepted Manuscript” means post-review text before typesetting.
- Follow The DOI: The link to the journal site should match the same text and figures.
- Review The Article Type: Research article, review, editorial, letter—each carries different vetting norms.
Reading Banners, Badges, And IDs
PMC pages include labels that tell you what you’re viewing. Here’s how to read them.
PMCID Versus PMID
PMCID is the archive identifier assigned by PMC. PMID is a PubMed identifier for the citation index. You’ll often see both. The presence of a PMCID doesn’t speak to the review status by itself; it only signals the item sits in the archive.
Preprint Notices
Preprint entries carry a large notice that says the research hasn’t been reviewed by a journal. Many also include links to the preprint server record. Some add community comments or updates when a version later appears in a journal.
Accepted Manuscript Notes
For manuscripts deposited through NIHMS, look for phrases such as “author accepted manuscript.” That label indicates the content has passed referee checks but isn’t the final typeset article.
Why Some Non-Journal Items Appear In The Archive
PMC was built to preserve and provide access to the biomedical literature. That mission includes a range of formats. Book chapters, technical reports, and supplemental materials help readers understand methods and context. These records may undergo editorial review, but they’re not the same as anonymous referee reports at a research journal. Treat them as scholarly resources with varied screening.
Practical Tips For Students And Clinicians
If you need a paper for coursework or patient care guidelines, stick to articles with journal metadata visible on the PMC page. Use the DOI to confirm the publication on the journal site. If you land on a preprint, look for a later version. Many PMC records link the preprint to the final paper once it’s out.
When A Preprint Is All You Have
Early data can be useful, especially in fast-moving areas. Read the methods closely, check the sample size, and look for open data or code. Treat claims as provisional until a journal version appears. If you’re writing an assignment or a policy memo, cite the status plainly as a preprint.
Common Misunderstandings, Fixed
“PMC Reviewed This Paper”
The archive curates and labels content, but it doesn’t run a referee process for submissions. Journals and peer communities do that work. PMC’s job is access and preservation, plus clear signals about each item’s status.
“Everything In The Archive Is Journal-Reviewed”
Most research articles arrive after journal checks, yet the archive also holds preprints and other content. That mix makes it handy, since you can read early results and the final paper in one place, but it also means you should scan labels before citing.
Walkthrough: Checking A Record Step-By-Step
Here’s a compact process you can use for any PMC page. It works whether you’re reading on a laptop or phone.
- Open The PMC Page: Start with the abstract and top banner.
- Identify The Record Type: “Preprint,” “Author Manuscript,” or journal “Published Article.”
- Locate The Journal Details: Journal title, year, volume, issue, pages, DOI.
- Check Version Links: Many pages show “Published in” with a link to the journal PDF.
- Note The License: Creative Commons terms can differ between versions.
- Record The IDs: Save the PMCID and DOI for your reference list.
Signals That Confirm Journal Review
These markers tell you the work passed refereeing at a journal:
- Clear journal citation with volume/issue/page range
- “Accepted manuscript” or “Published in” note on the page
- Publisher logo or typeset PDF linked or embedded
- DOI that resolves to the journal site
Where To Learn More About Policies
You can read plain-English explanations from official sources. The U.S. National Library of Medicine explains how PubMed and PMC differ, and NIH describes how preprints appear and why they’re labeled. Linking these references while you write assignments or lab notes helps readers verify status.
Field Guide: What The Page Labels Mean
This table decodes common labels and how to act on them during reading or citing.
| Label Or Field | What It Tells You | How To Act On It |
|---|---|---|
| “Preprint” Banner | Early manuscript, no journal referee reports yet | Use with care; watch for later journal version |
| “Author Accepted Manuscript” | Post-review text accepted by a journal | Safe to cite as peer-reviewed; note version |
| Journal Citation + DOI | Published article with final editorial checks | Cite the journal record; download the typeset PDF |
| PMCID | Archive ID for full-text access and compliance | Include in reports that ask for public-access IDs |
Citing Responsibly From PMC
When you cite, match the status you’re using. If you read the journal PDF, cite the journal version. If you only have the accepted manuscript, include the DOI and note the version. If you rely on a preprint, say so in the citation. Clear labeling helps readers and keeps course or grant reports tidy.
Two Trusted Links To Keep Handy
To backstop your checks, bookmark these pages: the PubMed vs. PMC explanation and the NIH preprint pilot overview. Both spell out what each record type means for readers.
Bottom Line For Readers
PMC is a gateway to full-text science. Most research papers you’ll open there already cleared journal referees. Some entries—preprints and non-journal content—serve different roles and carry clear labels. Read the banner, check the journal details, and match your citation to the version you used. With those habits, you get the access benefits of the archive while staying precise about peer review.