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 volunteersPhase 1
Controlled Human Infection Study of Orally Administered Trichuris Trichiura Eggs in Naïve Adults
George Washington University
- Location
- Washington D.C., DC + 1 other US site
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteersEarly Phase 1
Evaluating a Potential Pharmacokinetic Kratom-oxycodone Interaction Concurrent With Clinical Endpoints
Washington State University
- Location
- Spokane, WA
- Eligibility basics
- Ages 21–45
- RecruitingHealthy volunteersOvernight stay mentioned
Experimental Approach to Test Predictions of Body Weight Regulation Models
Pennington Biomedical Research Center
- Location
- Baton Rouge, LA
- Eligibility basics
- Ages 18–40
- RecruitingHealthy volunteersPhase 1
The Effects of Dietary Supplementation on Serum Protein Glycosylation
University of California, Davis
- Location
- Sacramento, CA
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteersEarly Phase 1
Impulsivity Domains and Subjective Response
Jessica Weafer
- Location
- Boston, MA + 1 other US site
- Eligibility basics
- Ages 21–25
- RecruitingHealthy volunteersPhase 1
Experimental Infection of Hookworm-naïve Adults With Dermally-applied Infectious Necator Americanus Hookworm Larvae
Baylor College of Medicine
- Location
- Washington D.C., DC
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteersPhase 1
Sex Differences in the Response to Abstinence From Alcohol.
Indiana University
- Location
- Indianapolis, IN
- Eligibility basics
- Ages 21–35
- RecruitingHealthy volunteersEarly Phase 1
Quadriceps Motor Unit Adaptation to Simulated Knee Injury
University of Central Florida
- Location
- Orlando, FL
- Eligibility basics
- Ages 18–30
- RecruitingHealthy volunteersPhase 1
Microelectrode Recordings From the Vagus Nerve in Awake Humans
University of Minnesota
- Location
- Minneapolis, MN
- Eligibility basics
- Ages 18–40
- RecruitingHealthy volunteersEarly Phase 1
Neurobehavioral Mechanisms Linking Childhood Adversity to Increased Risk for Smoking
Duke University
- Location
- Durham, NC
- Eligibility basics
- Ages 18–21
- RecruitingHealthy volunteersEarly Phase 1
Effect of C-peptide on Hypoglycemic Counterregulation
University of Cincinnati
- Location
- Cincinnati, OH
- Eligibility basics
- Ages 18–40
- RecruitingHealthy volunteersEarly Phase 1
Vascular Effects of High-Salt After Preeclampsia
Anna Stanhewicz, PhD
- Location
- Iowa City, IA
- Eligibility basics
- Ages 18–45 · Women only
- RecruitingHealthy volunteersEarly Phase 1
The Kidney's Response to Exercise in Heat, and the Impact of Vitamin B3 on This Response
Beth Israel Deaconess Medical Center
- Location
- Boston, MA + 1 other US site
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteersEarly Phase 1
Biologic Therapy to Prevent Osteoarthritis After ACL Injury
University of California, Los Angeles
- Location
- Los Angeles, CA
- Eligibility basics
- Ages 18–35
- RecruitingHealthy volunteersOvernight stay mentioned
Nighttime Synchrony of Your Nutrition and Circadian Health
University of Utah
- Location
- Salt Lake City, UT
- Eligibility basics
- Ages 18–35
- RecruitingHealthy volunteersEarly Phase 1
Opioid-Sparing and Pain-Reducing Properties of Syntocinon: A Dose-Effect Determination
University of Florida
- Location
- Gainesville, FL
- Eligibility basics
- Ages 21–45
- RecruitingHealthy volunteersEarly Phase 1
Researching Economical Adjuvants to Cancer Therapy
Florida State University
- Location
- Tallahassee, FL
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteersEarly Phase 1
Precision Dosing of Metformin in Youth With T2D
University of California, San Francisco
- Location
- Oakland, CA + 1 other US site
- Eligibility basics
- Ages 10–21
- RecruitingHealthy volunteersEarly Phase 1
Sex Differences in the Vascular Effects of E-cigarette Use
Anna Stanhewicz, PhD
- Location
- Iowa City, IA
- Eligibility basics
- Ages 18–24
- RecruitingHealthy volunteersEarly Phase 1
Role of Inflammation in Vascular Phenotype Associated With E-cigarette Use
University of Iowa
- Location
- Iowa City, IA + 1 other US site
- Eligibility basics
- Ages 18–24
- RecruitingHealthy volunteersPhase 1/Phase 2
Treatment of Relapsed/Refractory Intracranial Glioma in Patients Under 22 Years of Age
University of Miami
- Location
- Miami, FL
- Eligibility basics
- Ages 1–21
- RecruitingHealthy volunteersOvernight stay mentioned
Dietary Intervention to Mitigate Adverse Consequences of Night Work
Brigham and Women's Hospital
- Location
- Boston, MA
- Eligibility basics
- Ages 18–45
- RecruitingHealthy volunteersPhase 1
S-Nitrosylation (SNO) Therapy During Autologous Blood Transfusion
James Reynolds
- Location
- Cleveland, OH
- Eligibility basics
- Ages 18–35
- RecruitingHealthy volunteersEarly Phase 1
Bone Marrow Derived Stem Cells Mobilization for Treatment of Abnormal Endometrium
Hugh Taylor
- Location
- Orange, CT
- Eligibility basics
- Ages 18–40 · Women only
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.