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Showing 1–24 of 297 matching trials from the live ClinicalTrials.gov search.
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Filters: Intervention: Vitamin A supplementation Clear all
Completed Phase 4 Interventional

A Randomized Phase IV Control Trial of Single High Dose Oral Vitamin D3 in Pediatric Patients Undergoing HSCT

NCT03176849
View directory record Official record
Conditions
Vitamin D Deficiency, Stem Cell Transplant Complications, Pediatric Cancer, Blood Disorder, Pediatric Acute Myeloid Leukemia, Pediatric Acute Lymphoid Leukemia, Myelodysplastic Syndromes, Sickle Cell Anemia in Children, Aplastic Anemia, Thalassemia in Children
Interventions
Vitamin D3, Standard Vitamin D3 Supplementation
Dietary Supplement
Lead sponsor
Phoenix Children's Hospital
Other
Eligibility
1 Year to 25 Years
Enrollment
49 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2017 – 2019
U.S. locations
1
States / cities
Phoenix, Arizona
Source: ClinicalTrials.gov public record
Updated Nov 16, 2020 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Phase 1 Interventional Accepts healthy volunteers

Nutritional Intervention for Age-related Muscular Function and Strength Losses-Study 2

NCT02043171
View directory record Official record
Conditions
Sarcopenia
Interventions
Placebo, HMB plus Vitamin D, Non-Exercise, Exercise
Dietary Supplement · Drug · Behavioral
Lead sponsor
Metabolic Technologies Inc.
Industry
Eligibility
60 Years and older
Enrollment
238 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2014 – 2019
U.S. locations
1
States / cities
Ames, Iowa
Source: ClinicalTrials.gov public record
Updated Feb 10, 2019 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Accepts healthy volunteers

Impact of a Nutritional Supplement on Metabolic Health

NCT02239198
View directory record Official record
Conditions
Cardiovascular Disease Prevention
Interventions
Nutrition bar
Other
Lead sponsor
UCSF Benioff Children's Hospital Oakland
Other
Eligibility
18 Years and older
Enrollment
16 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2016 – 2017
U.S. locations
1
States / cities
Oakland, California
Source: ClinicalTrials.gov public record
Updated Apr 17, 2017 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Phase 4 Interventional Accepts healthy volunteers

The Effect of Vitamin D Supplementation on Muscle Power in Elite Cyclist

NCT01518725
View directory record Official record
Conditions
Muscle Power
Interventions
Vitamin D, Placebo
Dietary Supplement
Lead sponsor
Oklahoma State University
Other
Eligibility
18 Years to 35 Years
Enrollment
103 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2012 – 2013
U.S. locations
1
States / cities
Stillwater, Oklahoma
Source: ClinicalTrials.gov public record
Updated Apr 28, 2015 · Synced Sep 20, 2026, 10:43 AM EDT
Recruiting Phase 2 Interventional

Essential Amino Acid Supplementation for Femoral Fragility Fractures

NCT06050668
View directory record Official record
Conditions
Femoral Fracture, Fragility Fracture, Muscle Atrophy
Interventions
Essential Amino Acid Supplementation
Combination Product
Lead sponsor
Michael C Willey
Other
Eligibility
65 Years and older
Enrollment
60 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2024 – 2026
U.S. locations
2
States / cities
Iowa City, Iowa • Eugene, Oregon
Source: ClinicalTrials.gov public record
Updated Apr 14, 2026 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Results available

Vitamin D in HIV-Infected Patients on HAART

NCT01250899
View directory record Official record
Conditions
Vitamin D Deficiency, HIV
Interventions
Vitamin D
Dietary Supplement
Lead sponsor
University of California, Los Angeles
Other
Eligibility
18 Years to 90 Years
Enrollment
122 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2010 – 2012
U.S. locations
1
States / cities
Los Angeles, California
Source: ClinicalTrials.gov public record
Updated Nov 24, 2014 · Synced Sep 20, 2026, 10:43 AM EDT
Recruiting Not applicable Interventional Accepts healthy volunteers

Developing a Nutritional Supplement to Increase Collagen Synthesis in People

NCT06138106
View directory record Official record
Conditions
Dietary Supplements, Connective Tissue, Exercise
Interventions
Natural Product Supplement, Placebo control
Dietary Supplement
Lead sponsor
University of California, Davis
Other
Eligibility
18 Years to 30 Years
Enrollment
20 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2023 – 2026
U.S. locations
1
States / cities
Davis, California
Source: ClinicalTrials.gov public record
Updated Jun 28, 2026 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Phase 1 Interventional

Effect of Fish Oil and Vitamin C on Exercise-Induced Bronchoconstriction and Airway Inflammation in Asthma

NCT01057615
View directory record Official record
Conditions
Asthma
Interventions
Fish Oil, Ascorbic Acid, Fish Oil Placebo, Ascorbic Acid Placebo
Dietary Supplement
Lead sponsor
Indiana University
Other
Eligibility
18 Years to 40 Years
Enrollment
14 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2010
U.S. locations
1
States / cities
Bloomington, Indiana
Source: ClinicalTrials.gov public record
Updated Jan 30, 2011 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Early Phase 1 Interventional

A Pilot Study to Examine the Effects of Vitamin D Supplementation on Mitochondrial Bioenergetics in Older Adults

NCT02445066
View directory record Official record
Conditions
Low 25-hydroxyvitamin D Concentrations
Interventions
Vitamin D3
Dietary Supplement
Lead sponsor
Wake Forest University Health Sciences
Other
Eligibility
65 Years to 89 Years
Enrollment
15 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2014 – 2017
U.S. locations
1
States / cities
Winston-Salem, North Carolina
Source: ClinicalTrials.gov public record
Updated Aug 14, 2018 · Synced Sep 20, 2026, 10:43 AM EDT
Recruiting Early Phase 1 Interventional

Vitamin D in Patients With Stage I-III Colon Cancer or Resectable Colon Cancer Liver Metastases

NCT02172651
View directory record Official record
Conditions
Stage, Colon Cancer, Stage I-III Colon Cancer, Stage IV Colon Cancer With Resectable Liver Metastases
Interventions
Vitamin D3, Placebo
Drug
Lead sponsor
Dana-Farber Cancer Institute
Other
Eligibility
18 Years and older
Enrollment
80 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2014 – 2027
U.S. locations
1
States / cities
Boston, Massachusetts
Source: ClinicalTrials.gov public record
Updated May 12, 2026 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Accepts healthy volunteers

The Effects of Antioxidant Supplementation on Multiple Endurance Race Performance, Physiology, and Recovery.

NCT04314596
View directory record Official record
Conditions
Oxidative Stress, Muscle Strength, Resistance Training, Body Composition, Muscle Damage
Interventions
Cross Training Course, Oceanix
Other · Dietary Supplement
Lead sponsor
Applied Science & Performance Institute
Industry
Eligibility
18 Years to 45 Years
Enrollment
18 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2020
U.S. locations
1
States / cities
Tampa, Florida
Source: ClinicalTrials.gov public record
Updated Mar 18, 2020 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Accepts healthy volunteers

Effects of Vitamin C Enriched Hydrolyzed Collagen, PrimaColl™, Whey Protein, or Placebo on Collagen Synthesis

NCT05427279
View directory record Official record
Conditions
Effect of Food Supplement
Interventions
Placebo, Hydrolized Collagen, PrimaColl, Whey protein
Dietary Supplement
Lead sponsor
University of California, Davis
Other
Eligibility
18 Years to 30 Years
Enrollment
20 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2022 – 2024
U.S. locations
1
States / cities
Davis, California
Source: ClinicalTrials.gov public record
Updated May 7, 2026 · Synced Sep 20, 2026, 10:43 AM EDT
Not listed Not applicable Interventional Accepts healthy volunteers

Vitamin D3 Supplementation for Vitamin D Deficiency in Rotator Cuff Repair Surgery

NCT05009498
View directory record Official record
Conditions
Vitamin D Deficiency, Rotator Cuff Tears
Interventions
Vitamin D3 supplementation, Placebo
Dietary Supplement · Other
Lead sponsor
Community Memorial Health System
Other
Eligibility
18 Years to 65 Years
Enrollment
240 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2021 – 2024
U.S. locations
2
States / cities
Ventura, California
Source: ClinicalTrials.gov public record
Updated Aug 16, 2021 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Accepts healthy volunteers

Effects of a Seven-day BASIS™ Supplementation on Menopausal Syndromes and Measurements of the Urinary Vitamin B3 and Estradiol Levels in Pre-, Peri- and Post-menopause

NCT04841499
View directory record Official record
Conditions
Menopause
Interventions
BASIS™ (Crystalline Nicotinamide Riboside 250mg and Pterostilbene 50mg)
Drug
Lead sponsor
University of South Alabama
Other
Eligibility
35 Years and older · Female only
Enrollment
40 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2021
U.S. locations
1
States / cities
Mobile, Alabama
Source: ClinicalTrials.gov public record
Updated Nov 17, 2021 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Accepts healthy volunteers

Vitamin D3 Supplementation to Prevent Respiratory Tract Infections

NCT04596657
View directory record Official record
Conditions
Respiratory Tract Infections, Covid19, Flu Like Illness
Interventions
Vitamin D supplementation
Dietary Supplement
Lead sponsor
The Cooper Health System
Other
Eligibility
18 Years and older
Enrollment
877 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2020 – 2023
U.S. locations
1
States / cities
Camden, New Jersey
Source: ClinicalTrials.gov public record
Updated Dec 7, 2023 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Phase 3 Interventional Accepts healthy volunteers Results available

Impact of Maternal Vitamin A or Beta-Carotene Supplementation on Maternal and Infant Mortality in Bangladesh

NCT00198822
View directory record Official record
Conditions
Vitamin A Deficiency, Maternal Mortality, Infant Mortality
Interventions
Vitamin A or Beta-Carotene Supplements
Dietary Supplement
Lead sponsor
Johns Hopkins Bloomberg School of Public Health
Other
Eligibility
15 Years to 49 Years · Female only
Enrollment
59,666 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2001 – 2008
U.S. locations
1
States / cities
Baltimore, Maryland
Source: ClinicalTrials.gov public record
Updated Mar 6, 2012 · Synced Sep 20, 2026, 10:43 AM EDT
Terminated Phase 2 Interventional

Cholecalciferol Supplementation in Strengthening Inspiratory Muscles in Cholecalciferol-Deficient Patients With Chronic Obstructive Pulmonary Disease

NCT02877641
View directory record Official record
Conditions
Chronic Obstructive Pulmonary Disease, Muscle Weakness
Interventions
Cholecalciferol, Laboratory Biomarker Analysis, Multivitamin, Placebo, Questionnaire Administration
Dietary Supplement · Other
Lead sponsor
Roswell Park Cancer Institute
Other
Eligibility
50 Years and older
Enrollment
4 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2014 – 2017
U.S. locations
1
States / cities
Buffalo, New York
Source: ClinicalTrials.gov public record
Updated Feb 14, 2017 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Phase 1 Interventional

Safety and Immunologic Effect of Low Dose Versus High Dose Vitamin D3 in Multiple Sclerosis

NCT01024777
View directory record Official record
Conditions
Multiple Sclerosis, Vitamin D Deficiency
Interventions
Cholecalciferol
Drug
Lead sponsor
Johns Hopkins University
Other
Eligibility
18 Years to 55 Years
Enrollment
40 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2010 – 2013
U.S. locations
1
States / cities
Baltimore, Maryland
Source: ClinicalTrials.gov public record
Updated Feb 5, 2013 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Phase 3 Interventional Accepts healthy volunteers

Lactation Fortification Study

NCT01747668
View directory record Official record
Conditions
Lactation
Interventions
Similac Prenatal Vitamin soft-gel capsule, Placebo (soybean oil and dl-alpha-tocopheryl acetate)
Dietary Supplement
Lead sponsor
Abbott Nutrition
Industry
Eligibility
18 Years and older · Female only
Enrollment
89 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2012 – 2013
U.S. locations
6
States / cities
Indianapolis, Indiana • Dayton, Ohio • Kettering, Ohio + 3 more
Source: ClinicalTrials.gov public record
Updated May 30, 2013 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Accepts healthy volunteers

A New Paradigm for Vitamin D Sufficiency

NCT02969850
View directory record Official record
Conditions
New Biomarkers for Measuring Vitamin D Level
Interventions
Vitamin D Supplementation, Placebo, Calcium
Dietary Supplement · Other
Lead sponsor
NYU Langone Health
Other
Eligibility
60 Years to 90 Years · Female only
Enrollment
444 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2016 – 2019
U.S. locations
1
States / cities
Mineola, New York
Source: ClinicalTrials.gov public record
Updated Oct 21, 2021 · Synced Sep 20, 2026, 10:43 AM EDT
Completed Not applicable Interventional Results available

Vitamin C Supplementation Intervention

NCT04036110
View directory record Official record
Conditions
Heart Failure
Interventions
Vitamin C 500 mg, Vitamin C 1000 mg, Placebo
Dietary Supplement · Other
Lead sponsor
University of North Carolina, Chapel Hill
Other
Eligibility
18 Years to 99 Years
Enrollment
36 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2018 – 2020
U.S. locations
1
States / cities
Chapel Hill, North Carolina
Source: ClinicalTrials.gov public record
Updated Mar 8, 2021 · Synced Sep 20, 2026, 10:43 AM EDT
Terminated Phase 3 Interventional Results available

Efficacy and Safety of Cinacalcet in Pediatric Patients With Secondary Hyperparathyroidism (SHPT) and Chronic Kidney Disease (CKD) on Dialysis

NCT02138838
View directory record Official record
Conditions
Chronic Kidney Disease, Secondary Hyperparathyroidism
Interventions
Cinacalcet HCl, Standard of Care
Drug · Dietary Supplement
Lead sponsor
Amgen
Industry
Eligibility
6 Years to 17 Years
Enrollment
55 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2014 – 2016
U.S. locations
26
States / cities
Los Angeles, California • Wilmington, Delaware • Atlanta, Georgia + 22 more
Source: ClinicalTrials.gov public record
Updated Jun 28, 2020 · Synced Sep 20, 2026, 10:43 AM EDT
Terminated Not applicable Interventional

Vitamin D Supplement in Preventing Colon Cancer in African Americans With Colon Polyps

NCT00870961
View directory record Official record
Conditions
Colorectal Cancer, Precancerous Condition
Interventions
cholecalciferol, placebo
Dietary Supplement · Other
Lead sponsor
Northwestern University
Other
Eligibility
50 Years and older
Enrollment
22 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2009 – 2012
U.S. locations
2
States / cities
Chicago, Illinois
Source: ClinicalTrials.gov public record
Updated Sep 15, 2013 · Synced Sep 20, 2026, 10:43 AM EDT
Withdrawn Phase 2 Interventional

The Role of Antioxidant Supplementation in Keratoconus Patients

NCT02827747
View directory record Official record
Conditions
Keratoconus
Interventions
Antioxidants (Vitamins A,C,E) plus GSH, Placebo, Centrum, Dietary Sources
Other · Dietary Supplement · Combination Product
Lead sponsor
University of Miami
Other
Eligibility
18 Years to 45 Years
Healthy volunteers
Healthy volunteers not accepted
Timeline
2021 – 2023
U.S. locations
1
States / cities
Palm Beach Gardens, Florida
Source: ClinicalTrials.gov public record
Updated Aug 15, 2021 · Synced Sep 20, 2026, 10:43 AM EDT