Location · California
Clinical trials recruiting in California
1900 recruiting studies have at least one site in California; 700 accept healthy volunteers. Studies that need a specific condition are included too, so check each listing.
Want the research companies that run paid Phase 1 studies for healthy volunteers? Paid clinical trial companies in California.
1,900 recruiting studiesSource: ClinicalTrials.gov, refreshed October 27, 2026How we list studies
More recruiting studies (pay not posted)
- RecruitingHealthy volunteers
ChangeGradients: Promoting Adolescent Health Behavior Change
University of California, San Francisco
- Location
- San Francisco, CA
- Eligibility basics
- Ages 15–17
- RecruitingHealthy volunteers
MATAspire: Mental Health Awareness Tailored App for Substance Prevention and Integrated Resilience Education
California State University, Northridge
- Location
- Northridge, CA
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
Coaching and Leadership in Autism Support Settings
University of California, Los Angeles
- Location
- Los Angeles, CA
- Eligibility basics
- Ages 5+
- RecruitingHealthy volunteers
Trial Evaluating Nutritional Fiber in Digestive Symptoms of Endometriosis
LOAM Science
- Location
- San Francisco, CA
- Eligibility basics
- Ages 18–45 · Women only
- RecruitingHealthy volunteers
Cardiac Structure and Function in MPS
Children's Hospital of Orange County
- Location
- Orange, CA + 1 other US site
- Eligibility basics
- Ages 0 mo–99
- RecruitingHealthy volunteers
Geriatric Assessment and Management for Older Adults Undergoing Chemotherapy and Radiation Therapy for Head and Neck Cancer and Their Family Caregivers
City of Hope Medical Center
- Location
- Duarte, CA
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
Environmental Exposure Assessment in High-Risk and Early-Onset Breast Cancer Care
City of Hope Medical Center
- Location
- Duarte, CA
- Eligibility basics
- Ages 18+ · Women only
- RecruitingHealthy volunteers
Using Nicotine to Reverse Age-related Auditory Processing Deficits
University of California, Irvine
- Location
- Irvine, CA + 1 other US site
- Eligibility basics
- Ages 18–85
- RecruitingHealthy volunteersPhase 3
Basal Cell Carcinoma Chemoprevention Trial
VA Office of Research and Development
- Location
- San Diego, CA + 5 other US sites
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
A SMART Evaluation of an Adaptive Web-based AUD Treatment for Service Members and Their Partners
Stanford University
- Location
- Palo Alto, CA
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
Very Brief Exposure: Development of a Novel Exposure Modality for Social Anxiety Disorder in Transition-Age Youth
Children's Hospital Los Angeles
- Location
- Los Angeles, CA
- Eligibility basics
- Ages 16–22
- RecruitingHealthy volunteers
Genetics of Charcot Marie Tooth (CMT) - Modifiers of CMT1A, New Causes of CMT2
University of Iowa
- Location
- Los Angeles, CA + 17 other US sites
- Eligibility basics
- Any age listed
- RecruitingHealthy volunteers
Provider-Mediated Communication of Genetic Testing Results to At-Risk Relatives of Cancer Patients to Improve Genetic Counseling and Testing Rates, Family HOPE Study
City of Hope Medical Center
- Location
- Duarte, CA
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
Prospective Registry of ADC as First- and Second-line Treatment for Breast Cancer
University of California, San Francisco
- Location
- San Francisco, CA + 2 other US sites
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
Linking Youth to Pre-Exposure Prophylaxis (PrEP) Services
Westat
- Location
- San Francisco, CA + 3 other US sites
- Eligibility basics
- Ages 13–24
- RecruitingHealthy volunteers
Preventing School Exclusion and Opioid Misuse: Effectiveness of the Inclusive Skill-building Learning Approach (ISLA)
University of Oregon
- Location
- Capitola, CA + 2 other US sites
- Eligibility basics
- Ages 8–15
- RecruitingHealthy volunteers
UCLA Magnesium Formulation Athlete Study
University of California, Los Angeles
- Location
- Los Angeles, CA
- Eligibility basics
- Ages 18–35
- RecruitingHealthy volunteersPhase 2
Ongoing Lung Decline With Age Intensified Response
Cedars-Sinai Medical Center
- Location
- Los Angeles, CA
- Eligibility basics
- Ages 60+
- RecruitingHealthy volunteers
Effect of Messaging on Pragmatic Outcomes Within an Integrated Healthcare System
Kaiser Permanente
- Location
- Pasadena, CA
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
Pulse Oximeter Accuracy in Healthy Humans During Hypoxia
University of California, San Francisco
- Location
- San Francisco, CA
- Eligibility basics
- Ages 18–50
- RecruitingHealthy volunteers
Glaucoma Screening to Enhance At-Risk Californians' Health
University of California, San Francisco
- Location
- Fremont, CA + 1 other US site
- Eligibility basics
- Ages 50+
- RecruitingHealthy volunteers
Nutrition for Precision Health, Powered by the All of Us
RTI International
- Location
- Davis, CA + 12 other US sites
- Eligibility basics
- Ages 18+
- RecruitingHealthy volunteers
Research on Equity in Abortion Care by TeleHealth
University of California, San Francisco
- Location
- Oakland, CA
- Eligibility basics
- Ages 14–64
- RecruitingHealthy volunteers
K08 VR Fear Conditioning
University of California, Los Angeles
- Location
- Los Angeles, CA
- Eligibility basics
- Ages 18–70