Who can join
Studies for younger adults
These studies accept adults from 21 or younger and set an upper age limit of 45 or below, so they are aimed at younger adults. Being in the age range does not mean you qualify; screening decides.
674 recruiting studiesSource: ClinicalTrials.gov, refreshed October 26, 2026How we list studies
Studies
- RecruitingHealthy volunteers
Genesis Electrical Impedance Tomography (EIT): A Preliminary Study
University of Colorado, Denver
- Location
- Aurora, CO
- Eligibility basics
- Ages 0 mo–40
- RecruitingHealthy volunteers
Health Without Barriers/Salud Sin Barreras
Colorado State University
- Location
- Durango, CO
- Eligibility basics
- Ages 11–19
- RecruitingHealthy volunteers
The Effect Of Enamel Matrix Derivatives On Gingival Tissue Thickness
The University of Texas Health Science Center at San Antonio
- Location
- San Antonio, TX
- Eligibility basics
- Ages 18–18
- RecruitingHealthy volunteers
Microsurgery and Periodontal Healing
The University of Texas Health Science Center at San Antonio
- Location
- San Antonio, TX
- Eligibility basics
- Ages 18–18
- RecruitingHealthy volunteers
A Split-Mouth Clinical Trial Evaluating the Bond Failure Rate of a New Etch-Free Orthodontic Adhesive
University of Maryland, Baltimore
- Location
- Baltimore, MD
- Eligibility basics
- Ages 14–35
- RecruitingHealthy volunteers
Caffeine Optimization Versus Standard Caffeine Dosage (2B-2)
University of Arizona
- Location
- Tucson, AZ + 1 other US site
- Eligibility basics
- Ages 18–39
- RecruitingHealthy volunteers
Skeletal Health and Bone Marrow Composition in Newly Diagnosed Adolescents With Crohn Disease
Massachusetts General Hospital
- Location
- Boston, MA
- Eligibility basics
- Ages 13–20
- RecruitingHealthy volunteers
Skeletal Health and Bone Marrow Composition in Adolescents With Cystic Fibrosis
Massachusetts General Hospital
- Location
- Boston, MA
- Eligibility basics
- Ages 13–20
- RecruitingHealthy volunteers
Empowering Young Parents: Building Healthy Relationships Study
RTI International
- Location
- Camden, DE + 6 other US sites
- Eligibility basics
- Ages 14–21 · Women only
- RecruitingHealthy volunteersPhase 4
Beta-Blocker Influences on Inflammatory and Neural Responses to Stress
University of North Carolina, Chapel Hill
- Location
- Chapel Hill, NC
- Eligibility basics
- Ages 18–30
- RecruitingHealthy volunteers
Evaluating a Mat-Based Biometric Vibration System for Sleep and Daily Recovery
Florida International University
- Location
- Miami, FL
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteers
National Pregnancy Registry for Psychiatric Medications
Massachusetts General Hospital
- Location
- Boston, MA
- Eligibility basics
- Ages 18–45 · Women only
- RecruitingHealthy volunteers
Beyond Monoamines: The Role of the Nociceptin/Orphanin FQ Receptor in Major Depression
Mclean Hospital
- Location
- Belmont, MA
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteers
An Evaluation of an Online Sexual Assault Resistance Program (IDEA3)
University of Maryland, College Park
- Location
- Orlando, FL + 2 other US sites
- Eligibility basics
- Ages 17–24
- RecruitingHealthy volunteers
Neurophysiologic Biomarkers in Rett Syndrome
Children's Hospital of Philadelphia
- Location
- Los Angeles, CA + 5 other US sites
- Eligibility basics
- Ages 1–18 · Women only
- RecruitingHealthy volunteers
Impact of Increased Body Mass Index on Adolescent Fixed Orthodontic Treatment. A Prospective Longitudinal Study
University of Rochester
- Location
- Rochester, NY
- Eligibility basics
- Ages 12–18
- RecruitingHealthy volunteers
Effects of Breathing Training and Nitrate on Exercise at Simulated Altitude
Embry-Riddle Aeronautical University
- Location
- Daytona Beach, FL
- Eligibility basics
- Ages 18–40
- RecruitingHealthy volunteers
Effects of Hip Bump Manipulation Versus Sham Treatment in Healthy Adults
Dominican University New York
- Location
- Orangeburg, NY
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteers
Effects of HIIT vs. TRE on Type 2 Diabetes Risk
Syracuse University
- Location
- Syracuse, NY
- Eligibility basics
- Ages 14–30
- RecruitingHealthy volunteers
Cast Art for Kids With Extremity Fractures
United States Naval Medical Center, Portsmouth
- Location
- Portsmouth, VA
- Eligibility basics
- Ages 5–18
- RecruitingHealthy volunteers
Improving Sleep Quality During Pregnancy Using an Oral Appliance
Texas A&M University
- Location
- Dallas, TX
- Eligibility basics
- Ages 18–45 · Women only
- RecruitingHealthy volunteers
A Research Study Exploring How Musculoskeletal Function and the Autonomic Nervous System Relate to Visceral Pain in Women With and Without Dysmenorrhea (Painful Periods).
Azusa Pacific University
- Location
- Azusa, CA
- Eligibility basics
- Ages 18–35 · Women only
- RecruitingHealthy volunteers
Cerebellum and Autism: Regional Specialization for Social and Executive Functions
American University
- Location
- Washington D.C., DC
- Eligibility basics
- Ages 18–35
- RecruitingHealthy volunteers
Lutein, Zeaxathin, and Fish Oil Supplementation
Texas A&M University
- Location
- College Station, TX
- Eligibility basics
- Ages 18–45
Questions
If I fit this group, will I qualify?
Not necessarily. Age and sex limits are only the first filter. Each study has its own inclusion and exclusion criteria, and the research team decides at screening.
Where do these age and sex limits come from?
From the eligibility section of each study’s official ClinicalTrials.gov record. We don’t infer eligibility from anything else.