Cite the peer-reviewed article for any claim it now supports, and keep the preprint citation only where the preprint's distinct content still matters. The practical task is to confirm that the preprint and the journal article are the same work before you swap one for the other.
Match the versions first
- Compare the title, author list, and identifiers across the preprint record and the published article. arXiv search supports lookups by title, author, abstract, subject, identifier, and date range, so you can pull the preprint record and check these fields side by side.
- Look up the article's DOI in Crossref. A DOI lookup returns the metadata deposited for that DOI, which lets you compare the published record's title and authors against the preprint.
- Treat a mismatch as unresolved. If titles or author lists differ, check whether the published record names a preprint or related work before deciding the two are the same paper.
Update the draft
Replace the preprint citation with the journal article wherever the published version supports the claim you are making. Then check that the sentence still matches the published version's content, since the published article is the version readers will retrieve from the DOI.
When to keep the preprint
Keep the preprint citation when you rely on content that appears only in the preprint, such as material the published version does not carry. In that case, cite the preprint for that specific point and make clear which version you used.
Label the status
If you cite a preprint at all, identify it as a preprint so readers can tell its publication status. The NIH Preprint Pilot labels eligible life-science preprints in PMC and PubMed as preprints for exactly this reason: readers need to distinguish publication status when they encounter the record.