Core: healthy volunteers
Phase 1 clinical trials recruiting now
Phase 1 (and early Phase 1) trials are usually the first time a medicine is studied in people. They are typically small, closely monitored, and many are run in dedicated research units, sometimes with overnight stays.
934 recruiting studiesSource: ClinicalTrials.gov, refreshed October 27, 2026How we list studies
Studies
- RecruitingPhase 1Overnight stay mentioned
A Safety and Tolerability Study of HJB647 in Heart Failure Participants With Reduced Ejection Fraction
Novartis Pharmaceuticals
- Location
- Bradenton, FL + 4 other US sites
- Eligibility basics
- Ages 18–100
- RecruitingPhase 1Overnight stay mentioned
Study to Assess the Use of Tezampanel for Opioid Withdrawal Syndrome in Treatment-Seeking Patients With Opioid Use Disorder
Proniras Corporation
- Location
- Indianapolis, IN
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1Overnight stay mentioned
A Study of LTX-001 In Adult Participants With Acute Exacerbation of Schizophrenia
Leal Therapeutics, Inc
- Location
- Little Rock, AR + 9 other US sites
- Eligibility basics
- Ages 18–55
- RecruitingPhase 1Overnight stay mentioned
Determining Efficacy and Safety of BXCL501 in Agitation Associated With Pediatric Schizophrenia and Bipolar Disorder
BioXcel Therapeutics Inc
- Location
- Anaheim, CA + 3 other US sites
- Eligibility basics
- Ages 10–17
- RecruitingPhase 1/Phase 2Overnight stay mentioned
A Study to Investigate Lithium Brain/Plasma Pharmacokinetics and Safety of an AL001 Oral Capsule Compared to a Marketed Immediate-release Lithium Carbonate Capsule in Subjects With Bipolar I Disorder
Alzamend Neuro, Inc.
- Location
- Boston, MA
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1Overnight stay mentioned
MAD Study to Assess the Safety, Tolerability, PKs and Efficacy of YJ001 for Spray Use in Patients With DPNP
Zhejiang Hanmai Pharmaceutical Technology Co., Ltd.
- Location
- Fredericksburg, TX
- Eligibility basics
- Ages 18–80
- RecruitingHealthy volunteersPhase 1
Neuropharmacologic Imaging and Biomarker Assessments of Response to Acute and Repeated-Dosed Ketamine Infusions in Major Depressive Disorder
National Institute of Mental Health (NIMH)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–65
- RecruitingHealthy volunteersPhase 1
Nicotinic Receptor Genetic Variation and Alcohol Reward
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 21–60
- RecruitingHealthy volunteersPhase 1/Phase 2
Repeat Peripheral Blood Stem Cell Transplantation for Patients With Sickle Cell Disease and Falling Donor Myeloid Chimerism Levels
National Heart, Lung, and Blood Institute (NHLBI)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 2–80
- RecruitingHealthy volunteersPhase 1
Imatinib to Increase RUNX1 Activity in Participants With Germline RUNX1 Deficiency
National Cancer Institute (NCI)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–120
- RecruitingHealthy volunteersPhase 1
Induced Blood-Stage Malaria in Healthy Malaria-Naive Adults to Assess the Safety and Infectivity of Plasmodium Vivax Challenge Agent and Evaluate Transmission in Mosquito Feeding Assays
National Institute of Allergy and Infectious Diseases (NIAID)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–54
- RecruitingHealthy volunteersPhase 1
Environment and Alcohol: A Pilot Study
National Institute on Drug Abuse (NIDA)
- Location
- Baltimore, MD
- Eligibility basics
- Ages 21–100
- RecruitingHealthy volunteersPhase 1
Epstein-Barr Virus (EBV) gH/gL/gp42-Ferritin Nanoparticle Vaccine With or Without gp350-Ferritin in Healthy Adults With or Without EBV Infection
National Institute of Allergy and Infectious Diseases (NIAID)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–29
- RecruitingHealthy volunteersPhase 1
PET Imaging of Phosphodiesterase-4 (PDE4) in Volunteers With Alzheimer Disease (AD) or Mild Cognitive Impairment (MCI)
National Institute of Mental Health (NIMH)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 50–100
- RecruitingHealthy volunteersPhase 1
First-in-Human Evaluation of [11C]JMJ-129-d2 for PDE4D Imaging in Healthy Volunteers
National Institute of Mental Health (NIMH)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–105
- RecruitingHealthy volunteersEarly Phase 1
Study Brain Mechanisms of Frustration With Magnetoencephalography in Healthy Volunteers
National Institute of Mental Health (NIMH)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–55
- RecruitingHealthy volunteersEarly Phase 1
Sensory Tests of Cigarettes for Identification of Flavors in Current Daily Smoking Adults
Roswell Park Cancer Institute
- Location
- Buffalo, NY
- Eligibility basics
- Ages 21+
- RecruitingHealthy volunteersPhase 1
Evaluating the Dose, Safety, Tolerability, and Immunogenicity of Mosaic Hexavalent Influenza Vaccine VRCFLUMOS0116-00-VP (FluMos-v2) With and Without ALFQ Adjuvant in Healthy Adults
National Institute of Allergy and Infectious Diseases (NIAID)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–50
- RecruitingHealthy volunteersPhase 1
A Vaccine (CMV-MVA Triplex Vaccine) for the Enhancement of CMV-Specific Immunity and the Prevention of CMV Viremia in Patients Undergoing Haploidentical Hematopoietic Stem Cell Transplant
City of Hope Medical Center
- Location
- Duarte, CA + 2 other US sites
- Eligibility basics
- Ages 18–75
- RecruitingHealthy volunteersPhase 1
A Safety and Immunogenicity Trial of OCU500, ChAd36 Vector Encoding SARS-CoV-2 Spike Vaccine Via Intranasal and Inhalational Routes in Previously Vaccinated Adults
National Institute of Allergy and Infectious Diseases (NIAID)
- Location
- Decatur, GA + 4 other US sites
- Eligibility basics
- Ages 18–64
- RecruitingHealthy volunteersPhase 1
Phase 1 Study of CH505 HIV Vaccine Nanoparticles and mRNA Boosters in Healthy Adults
National Institute of Allergy and Infectious Diseases (NIAID)
- Location
- Boston, MA + 1 other US site
- Eligibility basics
- Ages 18–55
- RecruitingHealthy volunteersPhase 1
Phase 1 Challenge Study Using rDEN2delta30-7169 to Evaluate Host-Pathogen Interactions in Primary, Homotypic, and Heterotypic Dengue Virus Infection
National Institute of Allergy and Infectious Diseases (NIAID)
- Location
- Bethesda, MD
- Eligibility basics
- Ages 18–50
- RecruitingHealthy volunteersPhase 1/Phase 2
SV2A in Older Adults
Yale University
- Location
- New Haven, CT
- Eligibility basics
- Ages 50+
- RecruitingHealthy volunteersPhase 1
The ENHANCE Study: taVNS and Psilocybin
University of Wisconsin, Madison
- Location
- Madison, WI
- Eligibility basics
- Ages 18–70
Who these studies look for
Phase 1 studies often have narrow eligibility: specific age and weight ranges, no recent participation in another study, no nicotine, and limits on medications. Some Phase 1 studies recruit patients rather than healthy volunteers, so check each listing.
Matching a page like this one never means you qualify. Each research team decides eligibility at screening.
Questions
Are Phase 1 trials riskier?
Every study carries risk. Phase 1 studies involve less human data about the product, which is why they are closely monitored. The informed consent document explains the known risks; read it carefully and ask questions before signing.
Why do some Phase 1 studies include overnight stays?
Staying in the unit lets staff dose on a precise schedule and collect samples around the clock. Where a record mentions an inpatient stay we flag it on the listing.