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

International Journal of Molecular Sciences operates the MDPI handling editor + academic editor pre-check model. After upload, an MDPI handling editor in-house staff performs the immediate technical pre-check, then an academic editor is assigned for the academic editor pre-check covering scope, scientific soundness, reference relevance, and methodology. The academic editor decides whether to send the paper for peer review.

A handling editor at IJMS typically handles 60 to 120 manuscripts per quarter on the technical pre-check side, while academic editors handle 20 to 40 manuscripts per year on the academic pre-check side; IJMS academic editors are working academics fitting IJMS editorial work around their own laboratories.

IJMS editorial culture is decisive: desk decisions are fast and scope problems surface within days. Papers that pass the IJMS MDPI immediate technical pre-check and academic editor pre-check have cleared the steepest filter in MDPI molecular sciences publishing.

Before the paper reaches external reviewers, an MDPI handling editor performs the immediate technical pre-check and an academic editor performs the academic editor pre-check for scope, scientific soundness, reference relevance, and methodology. About 40 to 50 percent of submissions are desk-rejected at this stage within days.

A desk rejection most often means 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 molecular sciences priority bar is not met.

The MDPI immediate technical pre-check confirms files are complete: manuscript with figures embedded, supplementary information separate, MDPI template formatting, reporting checklists where applicable (ARRIVE for animal work, MIQE for quantitative PCR, CONSORT for clinical-trial components), cover letter directed to the editor, conflict-of-interest declarations, ethics-statement documentation, IRB approvals, and data-availability statement.

The MDPI in-house handling editor reviews the immediate technical pre-check results and selects an appropriate academic editor based on subject area expertise. This step is administrative rather than scientific: the handling editor confirms the files are complete and routes the manuscript to a subject-matched academic editor, but does not judge the science. It is usually invisible in the portal because it resolves quickly, often within a day or two. If the status sits here longer than a few days, the most common cause is a routing delay while a suitable academic editor in your subspecialty is identified.

The academic editor performs the academic editor pre-check for scope (molecular sciences fit), scientific soundness, reference relevance (citations covering recent state-of-the-art), and methodology. The academic editor decides whether to send the paper for peer review.

In parallel with the academic editor pre-check, ambiguous-fit papers are discussed across the MDPI editorial team where peer academic editors weigh in on whether the paper would fit better at IJMS or at sister MDPI molecular sciences journals. This editorial consultation runs alongside the pre-check and adds 2 to 4 days to the timeline that is invisible to the author in the portal.

IJMS academic editors typically invite 2 to 3 external reviewers, with reviewer recruitment typically taking 3 to 7 days (faster than many publishers because MDPI maintains an active reviewer pool). The recruitment window can take longer for highly specialized molecular sciences subspecialties.

Once reviewers agree to review, the typical IJMS peer-review cycle lasts 1 to 3 weeks per reviewer, contributing to the 18 to 20 day median first decision. Reviewers are asked to evaluate molecular sciences significance, methodology rigor, and reproducibility. Reviewer reports for IJMS tend to be focused; 1500 to 2500 word reports are typical given the short peer-review cycle.

After reports return, the academic editor synthesizes them and weighs the recommendations into a single decision: accept, minor revision, major revision, or reject. At this point the portal status often shifts to "Required Reviews Complete" and then "Decision Pending," which signals the reports are in and the editor is finalizing the recommendation. Most papers go through 1 to 2 revision rounds before a final decision, so a first decision of major or minor revision is the common outcome rather than an outright accept. Once a decision is sent, the revision clock starts and the paper re-enters the same synthesis loop after you resubmit.

• Rejection within 1 to 3 days: MDPI immediate technical pre-check return for completeness issues.

• Rejection within 3 to 7 days: Academic editor pre-check return for scope, soundness, references, or methodology.

• Still Under Review after 1 week: Strong signal. Paper passed the technical and academic editor pre-checks.

• Still Under Review after 6 weeks: Reviewer-recruitment or reviewer-report delay. A polite inquiry via the MDPI SuSy submission system portal is appropriate.

• Status changes to "Decision Pending": Reports are in; expect a decision within 1 to 3 days.

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 right at IJMS's 18 to 20 day median 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 managing 20+ active papers per year 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.

MDPI asks reviewers at IJMS to evaluate four things specifically. 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 flagged at academic editor pre-check. When references are outdated or do not cover recent state-of-the-art, academic editor pre-check return within 3 to 7 days is common (reference relevance is a specific pre-check criterion). 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 (immediate technical pre-check + academic editor pre-check model with scope/scientific soundness/reference relevance/methodology criteria, 18 to 20 day median first decision, 2 to 3 reviewer model, 1 to 2 typical revision rounds), 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 typically draw from 2 to 3 molecular sciences subspecialty experts under an MDPI single-blind model. Editors screen and triage manuscripts before any reviewer sees them via the immediate technical pre-check + academic editor 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 the academic editor pre-check.