International Journal of Molecular Sciences 'Under Review': What Each Status Means

IJMS follows MDPI's editorial process: after upload, the Editorial Office (MDPI in-house staff) completes the technical and ethics pre-check, then an Academic Editor is invited to perform the editorial pre-check, which assesses whether the manuscript fits the journal's scope and meets the expected standards of scientific soundness. The Academic Editor may reject the manuscript, request revisions before peer review, or move it forward to peer review.

IJMS academic editors are working academics fitting IJMS editorial work around their own laboratories.

Papers that pass the technical pre-check and the editorial pre-check have cleared the screens that come before peer review.

Before the paper reaches external reviewers, the Editorial Office performs the technical pre-check and an Academic Editor performs the editorial pre-check for scope fit and scientific soundness. MDPI publishes no share of submissions rejected at this stage and no timing for it.

A desk rejection can mean the academic editor concluded that the work would fit better at a sister MDPI journal (Molecules for general molecular chemistry, Biomolecules for biomolecules-focused work, Cells for cell biology, Pharmaceuticals for pharmaceutical sciences) or that the scope or soundness bar is not met.

The technical pre-check verifies adherence to the Instructions for Authors and MDPI's Research and Publication Ethics policies, overall legibility of the manuscript and appropriate article type selection, and screens ethics and research integrity. Items it can touch include the cover letter, conflict-of-interest declarations, ethics-statement documentation, IRB approvals, the data-availability statement, and reporting checklists where applicable (ARRIVE for animal work, which IJMS requires at submission, and CONSORT for randomized clinical trials).

After the technical pre-check, the manuscript is assigned to an MDPI staff member in the Editorial Office, who coordinates the handling of the submission and acts as the primary liaison between the authors, reviewers, and the Academic Editor. The Editorial Office also compiles a list of proposed reviewers (author-recommended and Editorial Office-proposed) for the Academic Editor to validate. This step is administrative rather than scientific: MDPI staff do not make editorial decisions.

The Academic Editor assesses whether the manuscript fits the journal's scope (molecular sciences fit) and meets the expected standards of scientific soundness. The Academic Editor may reject the manuscript, request revisions before peer review, or move it forward to peer review, and if it proceeds, approves or modifies the list of reviewers to be invited.

The Editorial Office invites the reviewers approved by the Academic Editor, and at least two review reports are collected for each manuscript that proceeds to peer review. MDPI publishes no reviewer-recruitment time. The recruitment window can take longer for highly specialized molecular sciences subspecialties.

Once reviewers accept an invitation, they are generally given 7 to 10 days to submit their report (extensions are common), contributing to MDPI's median of about 17.5 days to first decision. Reviewers weigh molecular sciences significance, methodology rigor, and reproducibility.

After at least two reports are in, the Academic Editor evaluates the adequacy of the reviewers' comments and the overall scientific soundness and makes the first editorial decision: accept in current form, minor revision, reconsider after major revision, reject and decline resubmission, reject and encourage resubmission, or ask for additional reviewers. In SuSy the status moves to Pending decision while the Academic Editor assesses the peer review, and a revision decision moves it to Pending major or minor revisions (MDPI's 2022 status guide). Up to two rounds of major revision are usually allowed. Once a decision is sent, the revision clock starts and the paper re-enters review after you resubmit.

• Early rejection: can come from the technical pre-check (completeness or ethics issues) or the Academic Editor's editorial pre-check (scope or soundness). MDPI publishes no timing for either.

• Still Under review after 1 week: A good sign. Under review applies once the paper has been pre-checked.

• Still Under review well beyond the reported median (about 17.5 days): Reviewer-recruitment or reviewer-report delay. About 6 weeks is a conservative point for a polite inquiry via the MDPI SuSy submission system portal.

• Status changes to "Pending decision": The Academic Editor is assessing the peer review; MDPI does not publish how long this takes.

This is the most common anxiety we hear from IJMS authors during the active editorial window. The honest answer: no, 3 weeks at Under Review puts you close to MDPI's reported median of about 17.5 days to first decision. Reports may already be in editorial synthesis with the academic editor preparing the recommendation. Most reviewer-driven delays come from reviewer-recruitment timing for highly specialized molecular sciences subspecialties rather than slow reviews because MDPI maintains an active reviewer pool.

If the portal still says Under Review at the 4-week mark, the most likely explanation is that one of the assigned reviewers asked for an extension and the academic editor granted it. This is normal practice at IJMS.

What you should NOT do during the 3-to-4-week window is email the editorial office. IJMS academic editors are working academic molecular sciences researchers handling manuscripts around their own laboratories; an inquiry at 3 weeks adds friction without accelerating the timeline.

If your IJMS paper is rejected after review, the natural cascade depends on what the reviewers and academic editor cited:

Molecules is the natural MDPI cascade for general molecular chemistry papers where the molecular sciences fit at IJMS is too narrow.

Biomolecules is the MDPI cascade for biomolecules-focused work.

Cells is the MDPI cascade for cell biology papers.

Pharmaceuticals is the MDPI cascade for pharmaceutical sciences papers.

Biomedicines is the MDPI cascade for biomedical papers.

PLOS ONE is the external PLOS open-access cascade for multidisciplinary papers. PLOS ONE uses Editorial Manager at Editorial Manager submission portal; editorial contact plosone@plos.org.

Scientific Reports is the external Nature Portfolio open-access cascade. Scientific Reports uses the Nature submission portal at Nature manuscript-tracking system; editorial contact srep@nature.com.

Reviewers at IJMS commonly weigh four things. The table below maps each to actionable preparation.

Across IJMS manuscripts, we see three named patterns generate the most consistent reviewer concerns and the most common reasons papers miss the editorial bar or fail the pre-check. IJMS is broad, but the breadth does not mean a thin biomedical story will pass. The manuscript still needs a molecular-sciences contribution, current references, and enough methodological transparency for a fast review cycle.

Reference relevance gaps. When references are outdated or do not cover recent state-of-the-art, reviewers and the Academic Editor can push back (IJMS's instructions ask for the most recent and relevant references in the field). The strongest manuscripts cite recent state-of-the-art molecular sciences references.

Methodology controls gaps surface as reviewer requests. When experimental methods are thin on controls or replicates, reviewers consistently request additional experiments. The strongest revisions include comprehensive controls from the start.

MDPI molecular sciences cascade offers from academic editor. When the academic editor concludes the work is rigorous but the IJMS molecular sciences scope is not the best fit, transfer offers to Molecules (general molecular chemistry), Biomolecules (biomolecules-focused), Cells (cell biology), Pharmaceuticals (pharmaceutical sciences), or Biomedicines (biomedical) are common. MDPI editors take these transfers seriously.

Check whether your IJMS molecular mechanism is clear enough ->

Check whether your IJMS controls and replicate logic are reviewer-ready ->

Check whether your IJMS reference set supports the current field position ->

The first recurring failure is molecular-scope ambiguity. Authors often submit a cancer, inflammation, neuroscience, microbiology, or pharmacology paper because it contains molecules, but IJMS reviewers look for a molecular mechanism that changes interpretation. Stronger submissions make the mechanistic claim visible in the title, abstract, model figure, and final discussion paragraph.

The second failure is methods compression. MDPI's fast review workflow makes missing controls highly visible because reviewers have limited time to infer what happened. We often see otherwise plausible manuscripts weakened by unclear replicate counts, absent negative controls, low-resolution blot presentation, missing qPCR primer validation, incomplete animal randomization detail, or no raw-data availability path. These issues are fixable before the first decision if the author uses the waiting window deliberately.

The third failure is sibling-journal routing. Molecules, Biomolecules, Cells, Pharmaceuticals, and Biomedicines each absorb papers that are scientifically sound but not ideally framed for IJMS. A good response strategy does not treat rejection as generic failure. It translates the reviewer concerns into a narrower MDPI route or into external open-access alternatives such as PLOS ONE or Scientific Reports when scientific soundness is stronger than molecular-priority fit.

This page was created from MDPI's public IJMS instructions for authors at MDPI author instructions, MDPI editorial process documentation (technical pre-check plus editorial pre-check by an Academic Editor for scope fit and scientific soundness, a 17.5 day median first decision for papers published in the first half of 2026, at least two review reports, up to two usual rounds of major revision), and Manusights pre-submission review experience with IJMS-targeted manuscripts.

Source limitations: official guidance describes workflow mechanics, so the reviewer-risk guidance here is inferred from those sources plus Manusights manuscript-review patterns, not from private editorial records. In Manusights' manuscript-review archive, 50+ molecular biology, cell biology, oncology, and biomedical manuscripts turned on whether the molecular mechanism, controls, references, and reproducibility package were explicit enough for fast academic-editor and reviewer evaluation.

For the MDPI molecular sciences landscape beyond IJMS, start with the International Journal of Molecular Sciences journal hub, IJMS submission guide, IJMS review time guide, and IJMS cover letter guide.

Then compare Molecules, Biomolecules, Cells, Pharmaceuticals, Biomedicines, and external open-access alternatives such as PLOS ONE, Scientific Reports, and Heliyon. The choice across these titles depends on whether the central contribution is molecular sciences scope, general molecular chemistry, biomolecules, cell biology, pharmaceutical sciences, biomedical, multidisciplinary PLOS, Nature Portfolio open access, or Elsevier multidisciplinary.

Reviewers at IJMS are molecular sciences subspecialty experts under MDPI's single-anonymized model, and at least two review reports are collected. Editors screen and triage manuscripts before any reviewer sees them via the technical pre-check and the editorial pre-check, and preparing a response template that addresses methodology and reference relevance accelerates revision rounds substantially.

For a pre-upload check of your manuscript against the IJMS molecular-sciences-scope-plus-methodology bar before submission, our International Journal of Molecular Sciences pre-submission diagnostic flags the methodology and reference-relevance weaknesses most likely to surface in review.