NIH R21 Grants — Exploratory/Developmental Grant
Reviewed by Dr. Meng ZhaoLast reviewed June 9, 2026Data refreshed September 5, 2026Editorial standards
Novel, high-risk/high-reward exploratory research
Funding
Up to $275,000 direct costs over 2 years (combined)
Duration
Up to 2 years
Eligibility
Any qualified investigator; preliminary data not required
Activity code
R21
What is the NIH R21 grant?
The R21 is the NIH Exploratory/Developmental Research Grant — designed for novel, high-risk/high-reward research where preliminary data may be limited or absent. The total budget is capped at $275,000 in direct costs over the entire grant (typically split as $150K + $125K, but flexibility exists), and the maximum project period is 2 years.
Recent R21 awards from NIH RePORTER
Examples of funded R21 projects across the last two fiscal years. The matching-award count comes from the full result set; funding totals, averages, rankings, and examples use the first 500 records returned by NIH RePORTER. Figures reflect a snapshot last refreshed on September 5, 2026.
Example R21 projects from the sample
Sleep-driven reorganization of excitatory and inhibitory synaptic nanoarchitecture
1R21NS151357-01Michelle Bridi · WEST VIRGINIA UNIVERSITY, WV · $420,750 · awarded Aug 27, 2026 · NIHPROJECT SUMMARY/ABSTRACT Sleep loss is a prevalent problem that is caused by many environmental, social, and health factors. In particular, sleep disruption is common in many neurological conditions, ranging from neurodevelopmental disorders to neurodegenerative disease. However, our understanding of the role of sleep loss in these conditions is limited…
Deep Learning of Child Abuse Imaging: Improving Outcomes of Children Evaluated for Physical Abuse
1R21LM015417-01Farah Brink · RESEARCH INST NATIONWIDE CHILDREN'S HOSP, OH · $242,901 · awarded Aug 19, 2026 · NIHPROJECT SUMMARY Fractures are a common manifestation of physical abuse, with children <2 years at highest risk. The identification of healing fractures is crucial in the evaluation of physical abuse in a young child as these can suggest ongoing violence within the home and have serious implications for child protection. However, estimating time-since-injury…
Mechanistic Dissection of SRRM2-Mediated RNA Splicing and Subnuclear RNA Organization in Human Neurons
1R21MH144609-01Cheen Euong Ang · ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI, NY · $462,000 · awarded Aug 18, 2026 · NIHPROJECT SUMMARY Schizophrenia is a severe neuropsychiatric disorder with high heritability, yet the molecular mechanisms linking genetic risk to neuronal dysfunction remain poorly understood. Emerging evidence points to post- transcriptional RNA regulation, such as RNA-binding proteins like Serine/Arginine Repetitive Matrix protein 2 (SRRM2), as a critical…
Identifying and Understanding Suicide Risk among Young Children
1R21MH141459-01RANDY AUERBACH · COLUMBIA UNIVERSITY HEALTH SCIENCES, NY · $402,289 · awarded Aug 18, 2026 · NIHProject Summary Despite widespread prevention efforts, suicide remains a major public health concern. Most extant research has focused on suicide in adolescents and adults; yet suicide risk among children is understudied. Suicide is now the 3rd leading cause of death among 8-12-year-olds, reflecting a clear public health crisis. The pediatric emergency…
Mechanistic understanding of influenza virus inhibition by non-canonical ISG15
1R21AI202159-01Steven Baker · LOYOLA UNIVERSITY CHICAGO, IL · $231,000 · awarded Aug 18, 2026 · NIHPROJECT SUMMARY Viruses are highly evolved to infect specific cell types in permissive host species. This tropism is defined by the gene expression repertoire of their “preferred” host cell type, which provides the necessary co-factors to facilitate virus replication. Host gene expression is finely tuned to respond to infection, and vertebrate hosts rapidly…
Intestinal Epithelial Cellular Targets of Human Norovirus Infection
1R21AI202907-01SARAH BLUTT · BAYLOR COLLEGE OF MEDICINE, TX · $240,000 · awarded Aug 18, 2026 · NIHPROJECT SUMMARY Human noroviruses (HuNoVs) are the leading cause of acute viral gastroenteritis worldwide, responsible for nearly 700 million infections annually, yet no vaccines or antivirals are currently available. Progress toward therapeutic development has been hindered by incomplete understanding of viral pathogenesis and historical challenges in…
Social Media Use and Rejection Sensitivity: Impact of the menstrual cycle, social reward neurophysiology and online experiences
1R21MH145196-01Elizabeth Andersen · UNIV OF NORTH CAROLINA CHAPEL HILL, NC · $427,625 · awarded Aug 17, 2026 · NIHPROJECT SUMMARY Social media use is associated with increased risk of psychopathology in adolescents, yet the underlying mechanisms linking social media use with mental illness are poorly understood. Social media use facilitates near constant peer evaluation and social feedback, which amplifies the potential for rejection sensitivity, the heightened…
Clinical Trajectory-Based Modeling of C. difficile to Link Individual Risk Profiles to Healthcare Burden
1R21AI202888-01Seth Blumberg · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO, CA · $246,000 · awarded Aug 17, 2026 · NIHPROJECT SUMMARY C. difficile infection (CDI) remains one of the most burdensome healthcare-associated infections, causing sub- stantial morbidity, mortality, and healthcare costs. Most analytic frameworks treat CDI as a single event that consists only of symptomatic infection. This fails to capture the full clinical progression including asymptomatic…
ONC-SLEEP Collaborative: COMISA Collaborative Care Integration in Oncology
1R21CA318809-01Morhaf Al Achkar · WAYNE STATE UNIVERSITY, MI · $398,544 · awarded Aug 14, 2026 · NIHSleep problems affect most people with cancer yet often go unnoticed, driving fatigue, declines in daily functioning, and lower quality of life. A particularly harmful pattern is having both insomnia and obstructive sleep apnea (COMISA), which spans all ages and is linked to high blood pressure, heart disease, and higher mortality. While exact COMISA rates…
Microbial Drivers of Radiation Resistance and Large Cell Transformation in Mycosis Fungoides and Sezary Syndrome
1R21AI200485-01Pamela Allen · EMORY UNIVERSITY, GA · $234,750 · awarded Aug 14, 2026 · NIHAbstract Objectives and Aims: Cutaneous T-cell lymphoma (CTCL) is a rare incurable skin lymphoma. Large cell transformation (LCT) is a common complication associated with rapid progression, shorter response to radiation therapy (RT), and inferior survival. Our long-term goal is to develop microbiome-targeted strategies to improve RT efficacy in LCT. We…
Roles of DNMT3a-Mediated Oligodendrogenesis in Post-Stroke Dementia
1R21NS147536-01A1Ken Arai · MASSACHUSETTS GENERAL HOSPITAL, MA · $435,550 · awarded Aug 14, 2026 · NIHPROJECT SUMMARY/ABSTRACT White matter damage plays an important role in the pathophysiology of cerebrovascular disease and contributes to cognitive impairment and dementia. Oligodendrocytes, the primary cells in the white matter, do not proliferate independently. Therefore, their progenitor cells, known as oligodendrocyte precursor cells (OPCs), are…
Using a Superoxide Dismutase Mimetic to Mitigate Age-Associated, Radiation-Induced Cardiopulmonary Damage: Investigating the Role of Nitro-Oxidative Signaling and Mitochondrial Metabolism
5R21AI193780-02Bryan Allen · UNIVERSITY OF IOWA, IA · $155,500 · awarded Aug 13, 2026 · NIHPROJECT SUMMARY/ABSTRACT. An aging population faces unique health challenges, including increased susceptibility to ionizing radiation (IR) toxicities due to oxidative and nitrative metabolic changes. Elderly individuals are particularly vulnerable to IR-induced cardiopulmonary toxicities due to age-related physiological changes that impair tissue repair…
Funding institutes in the sample
| Institute | Awards | Funding |
|---|---|---|
| NIH | 495 | $141.8M |
| ALLCDC | 5 | $1.2M |
Most frequent institutions in the sample
- JOHNS HOPKINS UNIVERSITY — 17 awards
- WASHINGTON UNIVERSITY — 14 awards
- MASSACHUSETTS GENERAL HOSPITAL — 13 awards
- EMORY UNIVERSITY — 12 awards
- UNIVERSITY OF CALIFORNIA, SAN FRANCISCO — 12 awards
- UNIVERSITY OF IOWA — 10 awards
- UNIVERSITY OF PITTSBURGH AT PITTSBURGH — 10 awards
- UNIVERSITY OF MINNESOTA — 10 awards
Source: NIH RePORTER. Verify any award in the official record by searching its project number. See our data methodology for how this sample is built and its limitations.
Decision guide
Choose R21 when
Choose R21 when the idea is novel, the preliminary data are minimal or absent, and you can plausibly complete the work in 2 years. Strong R21s typically articulate a clear hypothesis test even without extensive prior work.
Choose another mechanism when
Skip R21 if your project is incremental on existing R01 work — reviewers expect genuine novelty. Skip if you need >2 years or >$275K. Don't use R21 just because you lack data; reviewers are getting stricter about novelty.
Who applies for R21
R21s are commonly used by both new and established investigators. New investigators use R21s to test a novel idea before committing it to an R01 application. Established investigators use them to pivot into adjacent areas or test risky ideas alongside their R01-funded work.
Compare nearby NIH grant mechanisms
Searchers often land on R21 while deciding between adjacent NIH activity codes. Compare scope, NIH staff involvement, budget scale, and applicant stage before choosing a funding opportunity.
Discrete, specified investigator-led research project
Small, short-term projects (pilot studies, secondary analyses, methods development)
Planning for clinical trials or large-scale studies
For broad grant lookup, use the NIH grant search to find funded examples by activity code, PI, institution, and award year.
Search tips for R21
- R21 success rates vary widely — some institutes essentially treat them as small R01s with strict 2-year limits.
- An R21 awarded to a PI sometimes precedes an R01 in the same area within 2–3 years.
Open NIH NOFOs for R21
NIH accepts R21 applications only through a notice of funding opportunity (NOFO). These 31 are open or opening soon; each page lists due dates, participating institutes, related notices, and the projects NIH funded under it.
- RFA-MH-27-125NIMH · next due Nov 9, 2026Mechanistic Evaluation of Therapeutic Targets derived from Treatable Traits to Improve CNS Outcomes in People with HIV (R21/R33 Clinical Trial Not Allowed)
- RFA-DA-26-056NIDA · next due Dec 3, 2026Accelerating the Pace of Substance Use Research Using Existing Data (R21 Clinical Trial Not Allowed)
- PAR-25-068NIDDK · next due Feb 16, 2027Pilot Studies of Biological, Behavioral and Social Mechanisms Contributing to HIV Pathogenesis Within the Mission of NIDDK (R21 Clinical Trial Not Allowed)
- PAR-25-357NEI · next due Feb 16, 2027NEI Research Grant for Vision-Related Secondary Data Analysis (R21 Clinical Trial Not Allowed)
- PA-25-304NIH · next due Feb 16, 2027NIH Exploratory/Developmental Research Project Grant (Parent R21 Clinical Trial Not Allowed)
- PA-25-306NIH · next due Feb 16, 2027NIH Exploratory/Developmental Research Project Grant (Parent R21 Clinical Trial Required)
- PAR-25-346NCI · next due Feb 16, 2027Exploratory/Developmental Bioengineering Research Grants (EBRG) (R21 Clinical Trial Not Allowed)
- PAR-25-321NCI · next due Feb 16, 2027Exploratory/Developmental Bioengineering Research Grants (EBRG) (R21 Clinical Trial Optional)
Search NIH grants by activity code
Find R21-funded PIs
R21 funding trends
R21 frequently asked questions
What is the page limit for an NIH R21?
The Research Strategy is 6 pages for an R21 (half of an R01).
Do I need preliminary data for an R21?
No. R21 funding announcements explicitly state preliminary data are not required. In practice, strong applications often include some, but the reviewers should not penalize lack of preliminary data per the funding mechanism design.
Can an R21 be renewed?
R21 awards are not renewable. The mechanism is designed for 2 years and out — typically followed by an R01 application if the work proceeds.
What is the typical R21 success rate?
R21 success rates have generally been similar to or slightly lower than R01 rates (typically 12–18%) in recent years. Variation by institute is large.