FY25 Enrollment Data from NIH-Supported Clinical Research Now Available

May 27, 2026

As part of NIH’s continued efforts to increase the transparency of the NIH research portfolio, data on the sex, race, ethnicity, and age of participants in fiscal year (FY) 2025 NIH-supported clinical research are now available. The FY25 data were presented at the 64th meeting of the Advisory Committee on Research on Women’s Health (ACRWH) on April 7, 2026. Data from previous years are available on the NIH Report Inclusion of Women and Minorities in Clinical Research page. 

NIH is committed to ensuring that the research we support benefits all those affected by the condition under study. When clinical studies appropriately represent participants across sex, race, ethnicity, and age, the resulting evidence is stronger, more applicable, and better positioned to improve health outcomes for all. 

  • NIH’s inclusion policies, the Policy and Guidelines on the Inclusion of Women and Members of Racial and/or Ethnic Minority Groups in Clinical Research and the Inclusion Across the Lifespan Policy, require scientifically appropriate inclusion of women, members of racial and/or ethnic minority groups, and individuals of all ages in clinical research.
  • The Policy on the Inclusion of Women and Members of Racial and/or Ethnic Minority Groups also requires analyses by sex, race, and/or ethnicity for NIH-defined Phase 3 clinical trials.
  • Applicable NIH-defined Phase 3 clinical trials must report results of those analyses in ClinicalTrials.gov.

Each year, NIH-supported investigators and recipients provide deidentified individual-level data on participant sex, race, ethnicity, and age at enrollment in progress reports. The aggregate FY25 data are shown below.

FY25 Enrollment Overview

  • NIH-funded clinical research enrolled a total of 11,048,927 participants worldwide: 8,202,424 participants enrolled at U.S. sites and 2,846,503 at non-U.S. sites.
  • A total of 720,577 participants were enrolled in NIH-defined Phase 3 clinical trials.

Enrollment by Sex

  • Women continue to be strongly represented in NIH-supported clinical research. In FY25, 57.8% of participants were female, 35.3% were male, and 7.0% were unknown or not reported (Figure 1).
  • For all demographic categories, participants are listed as unknown/not reported when no reportable response was available for that demographic item. This may occur when the participant did not provide a response within the listed reporting categories or when the information was otherwise unavailable.
This graphic is a pie chart showing the distribution of participants enrolled in NIH-funded clinical research by sex for fiscal year 2025. Female participants represented 57.8% of enrollment, male participants represented 35.3%, and participants whose sex was unknown or not reported represented 7.0%.

Figure 1: FY25 Enrollment in NIH-Funded Clinical Research by Sex

Enrollment by Race and Ethnicity

  • In FY25, 33.6% of U.S. participants identified as members of racial and/or ethnic minority groups.
  • The largest racial groups represented in U.S. clinical research were White (56.2% of participants) and Black or African American (14.0%) (Figure 2).
  • Hispanic or Latino participants represented 12.6% of U.S. participants (Figure 3).
This graphic is a bar chart displaying the racial distribution of participants enrolled in U.S.-based NIH-funded clinical research during fiscal year 2025. White participants represented 56.2% of enrollment, Black or African American participants represented 14.0%, Asian participants represented 4.4%, participants reporting more than one race represented 3.3%, American Indian or Alaska Native participants represented 1.2%, Native Hawaiian or Other Pacific Islander participants represented 0.3%, and participants whose race was unknown or not reported represented 20.7%.

Figure 2: FY25 Enrollment in U.S. NIH-Funded Clinical Research by Race

This graphic is a pie chart illustrating participant enrollment in U.S. NIH-funded clinical research by ethnicity for fiscal year 2025. Participants identified as Not Hispanic or Latino represented 71.6% of enrollment, Hispanic or Latino participants represented 12.6%, and participants whose ethnicity was unknown or not reported represented 15.8%.

Figure 3: FY25 Enrollment in U.S. NIH-Funded Clinical Research by Ethnicity

Enrollment by Age

  • Most participants in NIH research (57.2%) were adults 18-64 years of age. 17.2% of participants were children younger than 18 and about 17.6% were adults ages 65 and older. The remaining 8.1% were unknown or not reported (Figure 4).
  • Figure 5 provides a more detailed breakdown by participant age group. The largest age groups represented are 26-34 years, 35-44 years, and 55-64 years, respectively.
This graphic is a pie chart showing participant enrollment in NIH clinical research by broad age groups for fiscal year 2025. Adults ages 18–64 years represented 57.2% of participants, older adults ages 65 years and older represented 17.6%, children younger than 18 years represented 17.2%, and participants whose age was unknown or not reported represented 8.1%.

Figure 4: FY25 Enrollment in NIH-Clinical Research by Broad Age Groups

This graphic is a vertical bar chart presenting participant enrollment in NIH clinical research by detailed age groups for fiscal year 2025. Participants ages 26–34 years represented 12.3% of enrollment, ages 35–44 years represented 11.9%, ages 55–64 years represented 10.5%, ages 45–54 years represented 10.0%, unknown or not reported ages represented 8.1%, ages 18–21 years represented 6.8%, ages 22–25 years represented 5.8%, ages 65–69 years represented 5.8%, ages 70–74 years represented 4.8%, ages 75–79 years represented 3.4%, ages 6–12 years represented 3.3%, ages 1–5 years represented 2.3%, ages 16–17 years represented 2.3%, ages 13–15 years represented 2.1%, ages 80–84 years represented 1.9%, participants younger than 1 year with values other than 0–28 or 29–364 days represented 1.0%, ages 85–89 years represented 1.0%, ages 90 years and older represented 0.6%, ages 0–28 days represented 0.6%, and ages 29–364 days represented 0.1%. The chart shows that participants ages 26–34 years, 35–44 years, and 55–64 years were the largest age groups enrolled in NIH clinical research during FY25.

Figure 5: FY25 Enrollment in NIH-Clinical Research by Narrow Age Groups

Appropriate participant representation in NIH clinical research is fundamental to scientific excellence. Research with scientifically appropriate participant representation results in findings that are more reliable, more applicable, and more informative for clinical decision-making. NIH will continue to work with the research community to strengthen participant representation and ensure that the knowledge NIH research generates benefits all people affected by the condition under study.

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