Important NIH Update: BESH Studies Will No Longer Be Classified as Clinical Trials
A policy change effective for funding opportunities with due dates on or after May 25, 2026 affects how certain human studies are categorized — and funded.
What’s Changing?
The NIH has announced that Basic Experimental Studies with Humans (BESH) will no longer be classified as clinical trials. This is a significant shift that affects how investigators apply for funding and whether their studies must be registered on ClinicalTrials.gov.
This change applies to any funding opportunity with a due date on or after May 25, 2026. Studies already registered on ClinicalTrials.gov under the current rules are not affected by this change.
Key Definitions
What is an NIH Clinical Trial? NIH defines a clinical trial as a research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.
What is a BESH Study? A Basic Experimental Study with Humans (BESH) is a study that prospectively assigns human participants to conditions but does so to study basic aspects of phenomena (such as biological, psychological, or social processes) — without a specific intent to inform a clinical health outcome. Previously, BESH studies met the NIH clinical trial definition and had to be submitted accordingly. Going forward, they will not.
For detailed definitions and examples, visit the NIH resource page: Is My Project a Clinical Trial, Basic Experimental Study Involving Humans (BESH), or an Observational Study Involving Humans?
What Does This Mean for Investigators?
If you are submitting a new grant application:
- BESH studies may no longer be submitted through clinical trial funding opportunities. They must be submitted to non-clinical trial funding opportunities.
- Conversely, if your study is a clinical trial, it must be submitted through a clinical trial funding opportunity.
- NIH has not announced dedicated BESH-only funding opportunities at this time. BESH studies will fall under the “non-clinical trial” category of existing opportunities.
An important rule of thumb: If your funding opportunity announcement designates the study as a clinical trial, your study is a clinical trial — regardless of whether you believe it meets the BESH definition. The funding opportunity designation is what governs registration and reporting requirements at our institution. When in doubt, err on the side of registration.
If your study is already registered on ClinicalTrials.gov: No action is required. This policy change does not affect studies already registered under current rules.
If your study is funded by a funding opportunity with a due date from now until May 24, 2026: It will follow the old registration requirements and will require studies meeting the BESH definition to be registered as a clinical trial.
Why Does This Matter?
Not all investigators are aware of how their studies are classified — and this change adds a new layer to that determination. Some studies that were previously submitted and funded as clinical trials may now be categorized differently going forward. If you are planning a new submission, it is worth reviewing your study design against both the NIH clinical trial definition and the BESH definition before selecting a funding opportunity.
If you receive funding under a clinical trial opportunity, ClinicalTrials.gov registration and results reporting requirements still apply.
Questions?
If you are unsure how this change applies to your study, please reach out to our team at [email protected]. We’re here to help you navigate these definitions before you submit.
Categories Clinical Trials, Funding, Research