40 registrations that name vitamin D3 vs D2 as a study arm and are recruiting or about to, as ClinicalTrials.gov listed them on Oct 20, 2026. Read each listing for its full criteria and current status.
Kymata never assesses eligibility. Each listing names its own criteria; only its study team can say whether someone can join. Trial doses are given under the trial's monitoring and are not a schedule for anyone outside it.
Filter 40 registrations
Status
Phase
16US sites across 12 states
1
2 to 4
5 to 19
20 or more
All 40 registrations
RecruitingNCT05045066
Immunological Effects of Vitamin D Replacement Among Black/African American Prostate Cancer Patients
Early phase 1
Mayo Clinic
About 220 people
Started Dec 29, 2021
In plain words An early phase 1 study of vitamin D3 vs D2 in male participants 18 and older, run by Mayo Clinic. It plans to enroll about 220 people at 2 US sites.
Who it lists and where
Who the trial lists, as registered
Lists male participants 18 and older. Conditions: Localized Prostate Carcinoma; Stage IV Prostate Cancer AJCC v8; Locally Recurrent Prostate Carcinoma; Metastatic Prostate Carcinoma.
Pre-Registration:
African American males, age >= 18 years
Patients with a previous history of localized or metastatic or locally recurrent prostate cancer
Registration:
1 more inclusion criterion and the exclusion criteria are on the listing.
This early phase I is to find out how common vitamin D insufficiency is among African American patients with a history of prostate cancer that has not spread to other parts of the body (localized) or has spread to other places in the body (metastatic) and how vitamin D insufficiency affects the immune system. This study also aims to find out if replacing vitamin D results in normalization of the immune function. The full summary is on the listing.
Where, as registered
2 US sites in 2 states.
RecruitingNCT06919718
Impact of Vitamin D Supplements on Mental Health and Milk Composition in Mothers Living in Idaho
No phase
University of Idaho
About 80 people
Started Dec 4, 2024
In plain words A study of vitamin D3 vs D2 in female participants 18 to 64, run by University of Idaho. It plans to enroll about 80 people at 2 US sites.
Mothers (>/= 18 years of age) of newborn infants (within first 4 months postpartum) in Idaho
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D (Cholecalciferol ); Placebo
Registered summary
Mothers of preterm infants experience exaggerated emotional stressors compared to those typically associated with new motherhood, making these women particularly vulnerable to postpartum depression. As many as 70% of mothers of preterm infants experience postpartum depression compared to only 12.5% of those delivering full-term infants. The full summary is on the listing.
Where, as registered
2 US sites in 1 state.
RecruitingNCT04821544
Maternal Stress on Human Milk and Infant Outcomes
No phase
University of Idaho
About 500 people
Started May 1, 2021
In plain words A study of vitamin D3 vs D2 in female participants 18 to 50, run by University of Idaho. It plans to enroll about 500 people at 1 US site.
Mothers of newborn infants at Kootenai Health NICU and the Palouse region
The exclusion criteria are on the listing.
What it tests, as registered
Mindfulness-based intervention (with a focus on self-compassion; MBSC); Vitamin D
Registered summary
The overarching purpose of this study is to determine if a modified 8-week mindfulness-based intervention (with a focus on self-compassion; MBSC) or 8 weeks of 2000 IU vitamin D supplementation will reduce stress and increase self-compassion in mothers of preterm infants and beneficially modify the human milk produced, and subsequently improve infant health.
Where, as registered
1 US site in 1 state.
RecruitingNCT02705287
Vitamin D Dynamics in Women
Observational
Cornell University
About 160 people
Started Oct 28, 2024
In plain words An observational study of vitamin D3 vs D2 in female participants 20 to 39, run by Cornell University. It plans to enroll about 160 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists female participants 20 to 39. Conditions: Pregnancy.
Self-reported White and Black women
Age 20-39
Body mass index (BMI) 1or pre-pregnancy BMI (If currently pregnant) either 18.5-24.9 kg/m2 or greater than or equal to 30 kg/m2
Singleton pregnancy
2 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D dynamics-pregnant; Vitamin D dynamics-nonpregnant
Registered summary
The goal of this project is to utilize stable isotopically labeled vitamin D3 and state of the art mass spectrometric methodology to assess vitamin D dynamics during pregnancy in relation to relation to obesity and vitamin D binding protein genotype. At the conclusion of this study, the investigators will have obtained novel information on the absorption and utilization of vitamin D in women and the degree to which vitamin D utilization during pregnancy is impacted by genetic ancestry, vitamin D binding protein concentration and genotype and by excess adiposity. The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT07120997
Prunes Preventing Bone Loss in Perimenopause
No phase
Penn State University
About 124 people
Started Dec 11, 2025
In plain words A study of vitamin D3 vs D2 in female participants 44 to 55, run by Penn State University. It plans to enroll about 124 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists female participants 44 to 55; healthy volunteers accepted. Conditions: Perimenopausal Bone Loss.
Age 44 to 55 years
Not severely obese (BMI <35 kg/m\^2)
Healthy (determined by a screening questionnaire, physical and medical history by a certified nurse practitioner, complete metabolic panel, and complete blood count)
Willing to include prunes in their daily diet
5 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Prunes; Calcium supplement; Vitamin D Supplement
Registered summary
Dietary interventions of prune consumption during the transmenopausal period are innovative methods to prevent bone loss. Modern medicine does not intervene to prevent or attenuate this highly vulnerable period of bone loss which, if successfully attenuated, can potentially prevent/delay osteoporosis in women. The transmenopausal period represents an opportunistic window for the study because bone loss is at its greatest at this time, with females losing as much as 6-7% of bone. The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT07448974
Vitamin D and Type 2 Diabetes - Treat-To-Target
Phase 3
Tufts Medical Center
About 100 people
Started Aug 4, 2026
In plain words A Phase 3 study of vitamin D3 vs D2 in people 30 to 74, run by Tufts Medical Center. It plans to enroll about 100 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists people 30 to 74. Conditions: Prediabetes; Type 2 Diabetes (T2DM).
High-risk prediabetes ("at high risk for type 2 diabetes") defined by meeting the following 2 prediabetes criteria established by the American Diabetes Association (ADA) in the 2010 clinical practice guidelines:
2 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D (Cholecalciferol ); Placebo
Registered summary
This study tests whether taking a weekly dose of vitamin D, with the dose adjusted to reach a target blood vitamin D level, can help control blood sugar levels in adults at high risk of developing type 2 diabetes (prediabetes). Research suggests that vitamin D may play a role in blood sugar control. The goal of this study is to see whether adjusting the dose of vitamin D to reach a specific blood vitamin D level improves blood sugar control compared with a placebo (a look-alike pill without vitamin D). One hundred adults aged 30 to 74 with prediabetes will take part. The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT03621553
Vitamin D Homeostasis in Sarcoidosis
Phase 4
University of Texas Southwestern Medical Center
About 90 people
Started Jul 1, 2010
In plain words A Phase 4 study of vitamin D3 vs D2 in people 21 and older, run by University of Texas Southwestern Medical Center. It plans to enroll about 90 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists people 21 and older. Conditions: Sarcoidosis; Vitamin D Insufficiency.
Stable medical condition defined as no hospitalization or emergency room visit in the previous 3 months
No evidence of active pulmonary or systemic infection
No other active inflammatory disease,
No active malignancy.
1 more inclusion criterion and the exclusion criteria are on the listing.
What it tests, as registered
Ergocalciferol; Placebo; Calcium Citrate with Vitamin D2
Registered summary
This study evaluates the relationship between vitamin-D status and severity of sarcoidosis, and the effects of vitamin-D repletion in vitamin-D insufficient patients with sarcoidosis. Half the patients with sarcoidosis who are vitamin-D insufficient will receive standard vitamin-D supplementation via standard regimen while the other half will receive a placebo. Sarcoidosis patients who are vitamin-D sufficient will also act as controls.
Where, as registered
1 US site in 1 state.
RecruitingNCT07366086
Pediatric Safety Follow-up Study of Prior Treatment With Romosozumab for Osteogenesis Imperfecta
Phase 3
Amgen
About 71 people
Started Mar 18, 2026
In plain words A Phase 3 study of vitamin D3 vs D2 in people 5 to 19, run by Amgen. It plans to enroll about 71 people at 4 sites, 1 of them in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 5 to 19. Conditions: Osteogenesis Imperfecta.
What it tests, as registered
Vitamin D; Calcium
Registered summary
The primary objective of this trial is to evaluate the safety of romosozumab in participants with osteogenesis imperfecta (OI) that have completed Study 20200105, regardless of whether they received investigational product (romosozumab) until the last protocol-specified dose or ended investigational product early.
Where, as registered
1 US site in 1 state; also Germany (2), Japan (1).
RecruitingNCT05933499
Effect of Tirzepatide and Bimagrumab on Body Composition, Insulin Sensitivity, and Bone in Adults With Obesity
Phase 2
Massachusetts General Hospital
About 63 people
Started Nov 5, 2025
In plain words A Phase 2 study of vitamin D3 vs D2 in people 18 and older, run by Massachusetts General Hospital. It plans to enroll about 63 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists people 18 and older. Conditions: Obesity.
BMI ≥30 kg/m2 or ≥27kg/m2 with at least one weight-related medical condition
Have a history of at least one self-reported unsuccessful behavioral effort to lose body weight
Have an established primary care provider
The exclusion criteria are on the listing.
What it tests, as registered
Bimagrumab; Tirzepatide; Calcium/Vitamin D; Lifestyle and nutrition counseling
Registered summary
In adults with obesity seeking treatment, weight loss would ideally be composed almost exclusively of fat mass. However, loss of muscle mass and bone are unintentional consequences of weight loss, which may have negative effects on health by lessening improvements in glucose and insulin levels, reducing resting metabolic rate, and increasing the risk of falls and fractures. The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT04355572
Evaluation of the Clinical and Psychological Impact of Vitamin D Replacement in Adolescent Females at Risk for Polycystic Ovarian Syndrome (PCOS)
No phase
Yale University
About 60 people
Starts Sep 2026 (estimated)
In plain words A study of vitamin D3 vs D2 in female participants 13 to 21, run by Yale University. It plans to enroll about 60 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists female participants 13 to 21. Conditions: Polycystic Ovarian Syndrome in Adolescent Females; Vitamin D Deficiency.
What it tests, as registered
Vitamin D 4000IU daily; Placebo
Registered summary
This study is a double blind, placebo controlled, randomized trial of study subjects with PCOS and low vitamin D to 2 groups- placebo and vitamin D replacement. Participants and investigators will be blinded to treatment modality until the end of the trial period
Where, as registered
1 US site in 1 state.
RecruitingNCT07241585
Vitamin D Effects on Immune Microenvironment of Nonmelanoma Skin Cancer After Photodynamic Therapy (PDT)
No phase
Case Comprehensive Cancer Center
About 54 people
Started Feb 25, 2026
In plain words A study of vitamin D3 vs D2 in people 18 and older, run by Case Comprehensive Cancer Center. It plans to enroll about 54 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists people 18 and older. Conditions: Nonmelanoma Skin Cancer; Basal Cell Carcinoma; Squamous Cell Carcinoma.
Must be an adult participant (> 18 yrs) who is scheduled to undergo Mohs surgery or ED\&C within the Dermatologic Surgery unit of the Department of Dermatology, Cleveland Clinic.
Must have at least one BCC or SCC tumor eligible for removal by Mohs surgery.
The original tumor size prior to biopsy must be >1.0 cm (in the longest diameter).
Participants of any ethnic group are eligible for this trial.
2 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D (VitD); Placebo; Photodynamic therapy (PDT); Mohs surgery or electrodessication & curettage (ED&C) (standard of care)
Registered summary
This research study is for people who have been diagnosed with a nonmelanoma skin cancer (either basal cell carcinoma or squamous cell carcinoma) and are planning to receive either Mohs surgery or ED\&C (electrodessication \& curettage) as part of clinical care. The purpose of this study is to understand how photodynamic therapy (PDT) with or without Vitamin D can promote an immune response to skin cancer. The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT07654777
The Efficacy of Vitamin D Supplementation to Sustain Performance Outcomes
No phase
Walter Reed Army Institute of Research (WRAIR)
About 52 people
Started Jul 17, 2026
In plain words A study of vitamin D3 vs D2 in people 18 to 40, run by Walter Reed Army Institute of Research (WRAIR). It plans to enroll about 52 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists people 18 to 40; healthy volunteers accepted. Conditions: Acute Stress Reaction.
Male and non-pregnant, non-lactating females 18 to 40 (inclusive) years of age.
Females of child-bearing potential must be using some form of birth control, if sexually active (e.g., oral contraceptive, condom, intrauterine device, etc.)
Score of 80% or greater on a "Volunteer Comprehension Assessment" test. A maximum of two attempts is permitted.
Blood 25 hydroxy vitamin D \[25(OH)D\] levels at the Screening visit of 30 nmol/L (12 ng/mL) (inclusive) - < 75 nmol/L (30 ng/mL).
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D3 (Cholecalciferol); Oral Placebo Tablet
Registered summary
The goal of this clinical trial is to find out if vitamin D supplements help healthy adults maintain their cognitive and simple physical task performance and emotional state during highly stressful situations. The main question it aims to answer is: \- Does vitamin D help maintain cognitive and physical task performance and emotional state during highly stressful situations? Researchers will compare vitamin D to placebo (a look-alike tablet that contains no active ingredients) to see if vitamin D better maintain cognitive and physical task performance and emotional state during highly… The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT07369063
Impact of Vitamin D Therapy on Thyroid Function and Antibody Levels in Pediatric Graves' Disease
Phase 2
Northwell Health
About 30 people
Started Aug 1, 2025
In plain words A Phase 2 study of vitamin D3 vs D2 in people 9 to 17, run by Northwell Health. It plans to enroll about 30 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists people 9 to 17. Conditions: Graves Disease; Graves' Disease; Hyperthyroidism.
All new pediatric participants aged 9-17 years with a new diagnosis of GD who will be started on methimazole, will be offered to participate at the time of diagnosis.
Biochemical features include:
Suppressed TSH <0.1.
Elevated T3
4 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Ergocalciferol 50,000 IU; Methimazole
Registered summary
The goal of this randomized pilot feasibility clinical trial is to determine the feasibility of implementing a protocol for a larger trial to assess the effects of high-dose vitamin D supplementation in pediatric patients (9-17 years old) newly diagnosed with Graves' disease. The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT05877846
Precision Medicine and Physical Function
No phase
University of North Carolina, Chapel Hill
About 25 people
Started Nov 1, 2023
In plain words A study of vitamin D3 vs D2 in people 65 to 85, run by University of North Carolina, Chapel Hill. It plans to enroll about 25 people at 1 US site.
Who it lists and where
Who the trial lists, as registered
Lists people 65 to 85. Conditions: Frailty; Weakness, Muscle; Multiple Chronic Conditions.
English-speaking older adults aged 65 to 85 years (of all genders and sexes, race or ethnicity)
A University of North Carolina at Chapel Hill (UNC) Geriatrics Medicine clinic patient;
Chronic medical conditions -these are based on the 21 Medicare multiple chronic conditions (e.g., alcohol abuse, arthritis (osteoarthritis, rheumatoid), asthma, atrial fibrillation, autism spectrum disorders, cancer (breast, colorectal,…
The exclusion criteria are on the listing.
What it tests, as registered
Beta-hydroxymethyl butyrate supplement; Vitamin D supplement; Matching Beta-hydroxymethyl butyrate supplement without Vitamin D
Registered summary
The investigators aim to conduct a 12-week, single-arm, pre/post-intervention of b-hydroxy-methylbutyrate in persons aged 65 to 85 years to assess feasibility and acceptability of the intervention and study procedures, secondary outcomes of physical function and changes in multi-omics patterns, and exploratory outcomes that will allow the team to describe physical function phenotype. The investigators' primary outcomes are the: feasibility of the study procedures (including safety), feasibility of the intervention delivery, and acceptability of study procedures and measures. The full summary is on the listing.
Where, as registered
1 US site in 1 state.
RecruitingNCT06861062
Effects of Vitamin D3 and Yeast Beta-Glucan Supplementation on Glycemic Control and Cardiovascular Disease Risk in Patients With Type 2 Diabetes
No phase
Huazhong University of Science and Technology
About 2,500 people
Started Apr 8, 2025
In plain words A study of vitamin D3 vs D2 in people 40 to 79, run by Huazhong University of Science and Technology. It plans to enroll about 2,500 people at 5 sites, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 40 to 79. Conditions: Diabetes Mellitus, Type 2.
Type 2 diabetes mellitus diagnosed by a physician based on the diagnostic criteria outlined in the Guideline for the Prevention and Treatment of Diabetes Mellitus in China (2024 Edition);
Men or women aged 40-79 years;
Convenient access to the study centers and permanent residence in the vicinity for the next five years;
Voluntary participation and signed written informed consent.
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D3; yeast β-glucan; Vitamin D placebo; yeast β-glucan placebo
Registered summary
This study is a randomized, double-blind, placebo-controlled trial involving 2,500 individuals aged 40-79 with type 2 diabetes (T2D). The trial includes a 2-year intervention period followed by a 3-year post-intervention follow-up. The primary objective is to investigate (a) the effect of daily supplementation with vitamin D3 (1600 IU) or yeast β-glucan (600 mg) on glycemic control in patients with T2D and (b) whether daily supplementation with vitamin D3 (1600 IU) or yeast β-glucan (600 mg) reduces the predicted 10 year risk of atherosclerotic cardiovascular disease (ASCVD) in patients with… The full summary is on the listing.
Where, as registered
No US site; China (5).
RecruitingNCT06570889
VItamin D in pregnanCy for prevenTion Of eaRlY Childhood Asthma
Phase 3
Professor Klaus Bønnelykke
About 2,000 people
Started Dec 20, 2024
In plain words A Phase 3 study of vitamin D3 vs D2 in female participants 18 to 45, run by Professor Klaus Bønnelykke. It plans to enroll about 2,000 people at 1 site, none in the US.
Pregnant Danish women before week 26 with blood levels of EPA+DHA above 4.7% of total fatty acids
No current vitamin D intake above the recommended 400 IU/day
No endocrine-, heart-, kidney- or auto-immune disorders
No disorders requiring treatment with blood thinning medication
The exclusion criteria are on the listing.
What it tests, as registered
Cholecalciferol D3; Olive oil
Registered summary
The overall aim of the study is to develop a nutritional preventive vitamin D supplementation strategy in pregnancy for early childhood asthma/persistent wheeze during the first three years of life as we hypothesize that supplementation in higher doses than recommended could reduce the risk of disease development.
Where, as registered
No US site; Denmark (1).
RecruitingNCT03824106
Frailty Rehabilitation
No phase
McMaster University
About 324 people
Started Sep 2, 2022
In plain words A study of vitamin D3 vs D2 in people 65 and older, run by McMaster University. It plans to enroll about 324 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 65 and older. Conditions: Frailty.
Community-dwelling ≥65 years of age
Able to independently ambulate 25m with or without walking aid
At high risk for mobility disability/functional limitations
Received medical clearance
2 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Control; Group Exercise; Nutrition and Medication review; Protein Supplement; Vitamin D
Registered summary
Frailty is an important clinical state that contributes to falls, hospitalization, institutionalization and death. When an individual simultaneously has many health problems, a frailty "tipping point" may be triggered by even a minor stressful event such as adding a new drug or urinary tract infection. Our research suggests that approximately 23% of Canadians over age 65 are frail, and by age 85 this estimate increases to over 40%. The full summary is on the listing.
Where, as registered
No US site; Canada (1).
RecruitingNCT05043116
High-dose Vitamin D Supplement for the Prevention of Acute Asthma-like Symptoms in Preschool Children
Phase 2
Copenhagen Studies on Asthma in Childhood
About 320 people
Started Oct 1, 2022
In plain words A Phase 2 study of vitamin D3 vs D2 in people 12 months to 71 months, run by Copenhagen Studies on Asthma in Childhood. It plans to enroll about 320 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 12 months to 71 months. Conditions: Asthma in Children.
What it tests, as registered
Cholecalciferol D3; Oral placebo suspension
Registered summary
To investigate whether high-dose vitamin D supplementation may have a beneficial effect on secondary prevention in preschool children (1-5 years of age), with respiratory infections being the primary cause of acute exacerbations with asthma-like symptoms.
Where, as registered
No US site; Denmark (1).
RecruitingNCT07864662
Impact of Trout Fish, Cow Milk With Egg, Vitamin D Supplementation, and Dietary Education on Vitamin D Status, Undernutrition, and Neurocognitive Outcomes Among School Children in Pakistan: An Open-label Individually Randomized Controlled Trial
No phase
Aga Khan University
About 304 people
Started Aug 10, 2026
In plain words A study of vitamin D3 vs D2 in people 6 to 12, run by Aga Khan University. It plans to enroll about 304 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 6 to 12. Conditions: Vitamin D 25-Hydroxylase Deficiency; Undernutrition; Neurocognitive Development.
Aged 6-12 years
Enrolled in one of the selected AKESP schools
Parent/legal guardian provides written informed consent
Child provides written assent
3 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D supplement 4000 IU weekly; 200 grams of cooked trout fish; 250 milliliters of whole cow milk + whole egg
Registered summary
Vitamin D deficiency and undernutrition are major public health concerns globally, particularly among children in low-resource and high-altitude settings. In Pakistan, the recent national nutrition survey has reported alarmingly high prevalence rates of vitamin D deficiency, especially in Ghizer District of Gilgit-Baltistan, where 85% of children under five years of age are vitamin D deficient, placing them at heightened risk for rickets, impaired growth, weakened immune function, cognitive impairments, and long-term socio-economic consequences. The full summary is on the listing.
Where, as registered
No US site; Pakistan (1).
RecruitingNCT03989778
Vitamin D and Polycystic Ovarian Syndrome (PCOS)
Phase 2
Aga Khan University
About 300 people
Started Feb 1, 2023
In plain words A Phase 2 study of vitamin D3 vs D2 in people 18 to 36, run by Aga Khan University. It plans to enroll about 300 people at 2 sites, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 18 to 36; healthy volunteers accepted. Conditions: Infertility, Female; Infertility; Vitamin D Deficiency.
Females with age range 18- 36 years, from all ethnic background having primary infertility with diagnosis of PCOS when at least 2 of these 3 elements are present: hyperandrogenism, chronic anovulation and polycystic ovaries and Vitamin D…
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D
Registered summary
Primary Objectives: To evaluate the efficacy of metformin and Vitamin D supplementation on serum insulin and serum androgen levels (Total testosterone, Steroid Hormone Binding Globulin, Free Androgen Index) levels compared metformin alone in infertile Poly cystic ovarian females of reproductive age group. Secondary Objectives: To measure change in endometrial thickness/number of follicles and follicular size by day 12 trans-vaginal ultrasound in the intervention group i.e. combination of metformin and vitamin D supplementation
Where, as registered
No US site; Pakistan (2).
RecruitingNCT07647198
FATIMA Trial: EGCG and Vitamin D3 for Prevention of Fibroid Recurrence
Phase 2
Sheikh Shakhbout Medical City
About 240 people
Starts Aug 22, 2026 (estimated)
In plain words A Phase 2 study of vitamin D3 vs D2 in female participants 18 and older, run by Sheikh Shakhbout Medical City. It plans to enroll about 240 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists female participants 18 and older. Conditions: Uterine Fibroids (Leiomyoma).
Has voluntarily signed and dated the informed consent form before initiation of any screening or study-specific procedures.
Premenopausal females aged 18 years and older on the day of signing of the informed consent form.
Has a diagnosis of uterine fibroids that is confirmed by a pelvic ultrasound (transvaginal and/or transabdominal) performed during the screening period.
Has at least one or more of the following symptoms:
10 more inclusion criteria and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D and Green Tea; Placebo
Registered summary
The aim of this randomized controlled clinical trial is to evaluate the efficacy of green tea (EGCG) and vitamin D3 supplementation in preventing uterine fibroid recurrence following fibroid removal.
Where, as registered
No US site; United Arab Emirates (1).
RecruitingNCT04650880
Effect of Vitamin D on Ovulation Rate in Women With Polycystic Ovary Syndrome
No phase
The University of Hong Kong
About 220 people
Started Jan 26, 2021
In plain words A study of vitamin D3 vs D2 in female participants 18 to 40, run by The University of Hong Kong. It plans to enroll about 220 people at 3 sites, none in the US.
1 more inclusion criterion and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D; Placebo
Registered summary
This is a randomized double-blind controlled trial on the effect of vitamin D supplementation to assess the ovulation rate of women with polycystic ovary syndrome (PCOS) and other reproductive, endocrine and metabolic outcomes after one year of treatment.
Where, as registered
No US site; Hong Kong (3).
RecruitingNCT04775381
Total Post-thyroidectomy Hypocalcemia After Preoperative Cholecalciferol Supplementation
Phase 3
Hôpital NOVO
About 200 people
Started Jun 30, 2021
In plain words A Phase 3 study of vitamin D3 vs D2 in people 18 and older, run by Hôpital NOVO. It plans to enroll about 200 people at 6 sites, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 18 and older. Conditions: Hypocalcemia.
Patient ≥ 18 years old
Patient shall be operated on for a total thyroidectomy in one time for any indication
Written informed consent (IC) obtained
Patients with affiliation to the social security system
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D
Registered summary
This prospective study evalue the inflence of pre operative vit D3 administration on post operative hypocalcemia in patients undergoing Total thyroidectomy
Where, as registered
No US site; France (6).
RecruitingNCT06736002
Effects of Mega-dose Vitamin D Pulse and Maintenance Therapy on Seizure Frequency, Fatigue, and Quality of Life: A Prospective Study
No phase
Chin-Wei Huang
About 200 people
Started Feb 3, 2025
In plain words A study of vitamin D3 vs D2 in people of any age, run by Chin-Wei Huang. It plans to enroll about 200 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people of any age. Conditions: Epilepsy.
Aged 20 or above (inclusive)
Diagnosed patients (refractory epilepsy refers to those who have used more than two drugs, and each drug has reached the When epileptic seizures cannot be well controlled at standard reasonable treatment doses, it is called refractory…
There is no imaging evidence of persistence or expansion of brain damage in the past three years
Subjects or family members (caregivers) can comply with the trial plan and take vitamin D patients
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D; Placebo
Registered summary
This prospective study aims to evaluate the effects of mega-dose vitamin D pulse therapy followed by maintenance therapy on seizure frequency, fatigue, and quality of life in patients with epilepsy. Participants will receive vitamin D supplementation, and clinical outcomes will be assessed over time to determine its potential benefits on seizure control and patient-reported outcomes.
Where, as registered
No US site; Taiwan (1).
RecruitingNCT07641075
Effects of High-Dose Vitamin D on Hormones, Neuromuscular Function, Cognition, and Body Composition in Athletes
No phase
The Jerzy Kukuczka Academy of Physical Education in Katowice
About 200 people
Started Jul 1, 2025
In plain words A study of vitamin D3 vs D2 in people 17 to 60, run by The Jerzy Kukuczka Academy of Physical Education in Katowice. It plans to enroll about 200 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 17 to 60; healthy volunteers accepted. Conditions: Vitamin D 25-Hydroxylase Deficiency; Vitamin D Deficiency/Insufficiency.
a minimum of 8 years of training experience,
absence of injuries in the 6 months leading up to the assessments,
consistent engagement in training sessions a minimum of 5 times per week over the last 6 months.
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D supplementation; Placebo
Registered summary
This study aims to evaluate the effects of high-dose vitamin D3 supplementation on selected physiological, neuromuscular, and cognitive parameters in athletes. At the baseline visit, participants will undergo a series of assessments at the Functional Research Laboratory at AWF Katowice, including a 10 mL venous blood sample collection, body composition analysis (via InBody and DEXA scans), neuromuscular function evaluation using tensiomyography (TMG), and computerized cognitive tests via the Vienna Test System. The full summary is on the listing.
Where, as registered
No US site; Poland (1).
RecruitingNCT06571344
Vitamin D in Dialysis Patients - Diagnostic and Therapeutic Management
Observational
Medical University of Gdansk
About 160 people
Started Nov 1, 2022
In plain words An observational study of vitamin D3 vs D2 in people 18 and older, run by Medical University of Gdansk. It plans to enroll about 160 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 18 and older. Conditions: Vitamin D Deficiency Due to Chronic Kidney Disease.
CKD stage 5,dialysed patients with vitamin D deficiency or insufficiency (level of 25(OH)D < 30 ng/mL)
The exclusion criteria are on the listing.
What it tests, as registered
Cholecalciferol
Registered summary
The goal of this observational study is to learn about the effects of cholecalciferol administration, according to guidelines for the general population, on laboratory parameters of Chronic Kidney Disease-Mineral and Bone Disorder in dialysis patients, depending of the attained levels of vitamin D (25OH)D). The full summary is on the listing.
Where, as registered
No US site; Poland (1).
RecruitingNCT07288801
Vitamin D for Preventing Recurrent Preeclampsia in Pregnant Women
Phase 4
Nishtar Medical University
About 146 people
Started Aug 9, 2025
In plain words A Phase 4 study of vitamin D3 vs D2 in female participants 20 to 45, run by Nishtar Medical University. It plans to enroll about 146 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists female participants 20 to 45. Conditions: Pre-eclampsia; Pregnancy; Vitamin D.
Gestational age ≥ 20-weeks (on LMP method) ' - Past medical history of pre-eclampsia
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D; Placebo and standard of care
Registered summary
The goal of this clinical trial is to find out whether giving vitamin D to pregnant women who had pre-eclampsia in a previous pregnancy helps prevent the condition from coming back. The main question it aims to answer is: Does vitamin D supplementation reduce the chance of pre-eclampsia recurring in pregnant women with a history of pre-eclampsia? To answer this question, pregnant women attending the antenatal clinic at the Department of Obstetrics and Gynaecology, Nishtar Hospital Multan will be invited to join the study. The full summary is on the listing.
Where, as registered
No US site; Pakistan (1).
RecruitingNCT06045351
Efficacy of Injectable Vitamin D Supplementation in Females With Polycystic Ovary Syndrome
Phase 1
Aga Khan University
About 142 people
Started Jan 1, 2024
In plain words A Phase 1 study of vitamin D3 vs D2 in female participants 18 to 45, run by Aga Khan University. It plans to enroll about 142 people at 1 site, none in the US.
Recently diagnosed PCOS with presence of at least 2 of these 3 elements: clinical or biochemical signs of hyperandrogenism, chronic anovulation and polycystic ovaries (1) (from reports of available routine TVS), with VDD serum levels VD…
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D; Active Comparator
Registered summary
Poly cystic Ovarian Syndrome (PCOS) is an endocrine disorder of reproductive age defined by "the presence of any two out of three criteria: oligo and/or anovulation, excess androgen activity and/or polycystic ovarian morphology on ultrasound". Considering role of vitamin D (VD) (3, 4) and high prevalence (58%) of deficiency in PCOS of Pakistan. Researchers hypothesized that its correction would improve response to standard PCOS treatment. The full summary is on the listing.
Where, as registered
No US site; Pakistan (1).
RecruitingNCT07256769
Vitamin k, D-chiro Inositol and α-lactalbumin in Bone Homeostasis
Observational
Regina Elena Cancer Institute
About 134 people
Started Sep 29, 2025
In plain words An observational study of vitamin D3 vs D2 in female participants 35 to 70, run by Regina Elena Cancer Institute. It plans to enroll about 134 people at 2 sites, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists female participants 35 to 70. Conditions: Osteoporosis Secondary; Breast Cancer Females.
caucasian women aged between 35 and 70;
diagnosed with breast cancer undergoing treatment with aromatase inhibitors or tamoxifen + GnRH analogues or aromatase inhibitors + GnRH analogues not started more than 12 months ago, about to start treatment with oral bone resorption…
vitamin D levels below 30 ng/ml (test carried out no more than 6 months prior to the baseline/T0 visit)
patients able to comply with the procedures and/or requirements of the study
1 more inclusion criterion and the exclusion criteria are on the listing.
What it tests, as registered
Group 1: calcium carbonate/cholecalciferol; Group 2: Synostea® (calcium carbonate/cholecalciferol/vitamin K/α-lactalbumin/ d-chiro-inositol)
Registered summary
In women with breast cancer undergoing adjuvant hormone therapy, the marked tissue hypoestrogenism induced by therapy with aromatase inhibitors and/or tamoxifen ± GnRH analogues causes a significant acceleration in bone mass loss, with a consequent increased risk of fracture from the first year of therapy. It is therefore essential to start treatment with antiresorptive drugs and calcium and vitamin D supplementation. It has been hypothesized that vitamin K and α-lactalbumin have an effect in improving the absorption of calcium and vitamin D. The full summary is on the listing.
Where, as registered
No US site; Italy (2).
RecruitingNCT07293910
Vonoprazan vs Proton Pump Inhibitor With Vitamin D or Probiotics Based Triple Therapy for Eradication of Helicobacter Pylori Infection
Phase 2
Tanta University
About 132 people
Started Feb 15, 2026
In plain words A Phase 2 study of vitamin D3 vs D2 in people 18 to 80, run by Tanta University. It plans to enroll about 132 people at 1 site, none in the US.
Helicobacter pylori is a Gram-negative, spiral-shaped bacterium that infects up to 50% of the world's population, residing in the gastric mucosa and using the mucus layer for protection from the stomach's high acidity. Its clinical significance is profound: it is classified as a Group 1 carcinogen by the World Health Organization and is a primary cause of chronic gastritis, peptic ulcers, gastric lymphoma, and gastric carcinoma. The full summary is on the listing.
Where, as registered
No US site; Egypt (1).
RecruitingNCT05667090
Effects of Multiple Mega-dose of Vitamin D3 Supplementation on Ameliorating Moderate to Severe Chronic Pain in Hemodialysis Patients
No phase
Taipei Medical University Hospital
About 120 people
Started Mar 15, 2023
In plain words A study of vitamin D3 vs D2 in people 20 and older, run by Taipei Medical University Hospital. It plans to enroll about 120 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 20 and older. Conditions: Hemodialysis; Chronic Pain; Hyperparathyroidism.
Haemodialysis subject ≥ 20 years old
iPTH > 250 pg/mL
Chronic pain with visual analogue scale (VAS) score ≥ 4
Voluntary to check serum 25(OH)D levels two times by his/her own payment during the study
1 more inclusion criterion and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D; Placebo
Registered summary
Pain is a major complaint in hemodialysis (HD) patients. Concentrations of parathyroid hormone (PTH) \>250 pg/ml are associated with chronic pain. Visual Analogue Scale (VAS) score which is used to assess the pain severity is positively related to PTH levels. This study is aimed to assess the effects of multiple mega dosages vitamin D supplementations in HD patients with chronic pain. It's a single-center, parallel, double-blind randomized control trial that administrations of 576,000 IU once a week of vitamin D3 for 4 weeks or placebo are for 120 eligible subjects. The full summary is on the listing.
Where, as registered
No US site; Taiwan (1).
RecruitingNCT07115342
Effect of Combined Probiotics and Vitamin D on Symptoms of Allergic Rhinitis
No phase
Tanta University
About 120 people
Started Aug 1, 2025
In plain words A study of vitamin D3 vs D2 in people 18 to 65, run by Tanta University. It plans to enroll about 120 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 18 to 65. Conditions: Allergic Rhinitis; Allergic Rhinitis (AR).
What it tests, as registered
Standard Allergic Rhinitis Treatment; Combined Vitamin D and Probiotics Supplementation
Registered summary
The goal of this clinical trial is to learn if taking probiotics, vitamin D, or both together can help lower symptoms of allergic rhinitis (AR) and improve quality of life in adults. Allergic rhinitis is a condition that causes sneezing, nasal congestion, and itchy or watery eyes. The full summary is on the listing.
Where, as registered
No US site; Egypt (1).
RecruitingNCT07400757
Statin and Vitamin D Treatment in Patients With Thyroid Eye Disease
No phase
Taipei Veterans General Hospital, Taiwan
About 120 people
Started Feb 24, 2026
In plain words A study of vitamin D3 vs D2 in people 20 and older, run by Taipei Veterans General Hospital, Taiwan. It plans to enroll about 120 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 20 and older. Conditions: Thyroid Eye Disease, TED; Graves Ophthalmopathy.
Adults aged 20 years or older
Diagnosis of active thyroid eye disease with a Clinical Activity Score (CAS) of 3 or higher
Low-density lipoprotein cholesterol (LDL-C) level of 100 mg/dL or higher
The exclusion criteria are on the listing.
What it tests, as registered
Atorvastatin (Lipitor); Vitamin D
Registered summary
The goal of this clinical trial is to learn whether statin therapy and vitamin D supplementation can modify disease activity in patients with active thyroid eye disease. The study will also evaluate the safety of these treatments. The main questions it aims to answer are: * Does statin therapy change disease activity, as measured by changes in the Clinical Activity Score (CAS) and proptosis? * Does vitamin D supplementation change disease activity in patients with active thyroid eye disease? * Does combined treatment with statin and vitamin D produce different effects compared with either… The full summary is on the listing.
Where, as registered
No US site; Taiwan (1).
RecruitingNCT07534852
NIMA-Colon Cancer Study
No phase
Fundación Pública Andaluza para la Investigación de Málaga en Biomedicina y Salud
About 120 people
Started Jul 1, 2025
In plain words A study of vitamin D3 vs D2 in people 18 to 75, run by Fundación Pública Andaluza para la Investigación de Málaga en Biomedicina y Salud. It plans to enroll about 120 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 18 to 75. Conditions: Colon Cancer.
Adults aged 18 to 75 years.
Male and female participants.
Diagnosis of colon cancer at localized or locally advanced stages (TNM stages I-III).
Patients scheduled for primary surgical treatment.
The exclusion criteria are on the listing.
What it tests, as registered
Standard hypercaloric-hyperproteic nutritional supplementation; HMB-enriched hypercaloric-hyperproteic nutritional supplementation with vitamin D and calcium; Supervised exercise program; General physical activity recommendations
Registered summary
The goal of this study is to evaluate the effects of nutritional supplementation and physical activity interventions on recovery, muscle strength, nutritional status, inflammation, and metabolic health in adults with colon cancer undergoing surgery. Patients with colon cancer frequently experience loss of muscle mass, reduced physical function, and nutritional deterioration both before and after surgery, which may adversely affect recovery and quality of life. The full summary is on the listing.
Where, as registered
No US site; Spain (1).
RecruitingNCT07636733
The Effect of Vitamin D Supplementation on the Anti-inflammatory Response in Periodontal Diseases
No phase
Recep Tayyip Erdogan University Training and Research Hospital
About 120 people
Started Jun 3, 2026
In plain words A study of vitamin D3 vs D2 in people 18 to 70, run by Recep Tayyip Erdogan University Training and Research Hospital. It plans to enroll about 120 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 18 to 70; healthy volunteers accepted. Conditions: Periodontal Diseases; Gingivitis; Vitamin D Deficiency.
Study groups will be formed according to the 2017 Periodontal Disease Classification. Accordingly:
Periodontally healthy; absence of bleeding on probing, erythema, edema, patient symptoms, attachment, and bone loss
Gingivitis; patients with an average gingival index ≥0.5 according to Löe and Silness
Stage I-II periodontitis; patients with CAL 1-2 or 3-4 mm and a maximum PPD ≤5 mm, showing radiographic horizontal bone loss up to the coronal third of the root (15%-33%), but without tooth loss due to periodontitis
1 more inclusion criterion and the exclusion criteria are on the listing.
What it tests, as registered
Non-surgical periodontal treatment; Vitamin D administration; Oral Hygiene Education and Patient Motivation
Registered summary
A review of the literature revealed that while there are studies investigating the relationship between vitamin D and periodontal disease, there are no studies investigating the anti-inflammatory effect of vitamin D on periodontal disease. Investigators hypothesized that the increased incidence of periodontal disease in individuals with vitamin D deficiency might be due not only to pro-inflammatory effects but also to impaired bone metabolism and a decrease in the anti- inflammatory mechanism. The full summary is on the listing.
Where, as registered
No US site; Turkey (Türkiye) (1).
RecruitingNCT06708741
Regime for Vitamin D Maintenance in Post-Operative Patients
Phase 3
Sengkang General Hospital
About 100 people
Started Jan 1, 2026
In plain words A Phase 3 study of vitamin D3 vs D2 in people 21 to 65, run by Sengkang General Hospital. It plans to enroll about 100 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 21 to 65; healthy volunteers accepted. Conditions: Sarcopenia.
Serum 25-hydroxyvitamin D levels between 30-50ng/ml at 4-6 weeks after operation
aged 21-65 years
ability to provide informed consent
accepts to take vitamin D supplements post-operatively and
1 more inclusion criterion and the exclusion criteria are on the listing.
What it tests, as registered
Vitamin D
Registered summary
Vitamin D plays a significant part calcium and phosphate haemostasis, thus, intrinsically critical for bone health. Increasing evidence also reveal that insufficient serum vitamin D levels also result in poor muscle health with such individuals having a compromised muscle building potential (4 times slower muscle building). Muscle health is a critical component of a post-surgical patient recovery, with impaired muscle function leading to reduced functional ability, resulting in a poorer quality of life. The full summary is on the listing.
Where, as registered
No US site; Singapore (1).
RecruitingNCT06138249
Cholecalciferol and Calcifediol Are Both Useful to Improve Vitamin D Serum Levels
No phase
Azienda Ospedaliero-Universitaria Consorziale Policlinico di Bari
About 90 people
Started Jul 1, 2023
In plain words A study of vitamin D3 vs D2 in people 18 to 80, run by Azienda Ospedaliero-Universitaria Consorziale Policlinico di Bari. It plans to enroll about 90 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 18 to 80. Conditions: Hypovitaminosis D.
Hypovitaminosis D (<20ng/mL)
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D
Registered summary
Patients with hypovitaminosis D are randomized into three arms of treatment: Group A: Calcifediol 0,266mg each month Group B: Cholecalciferol 25000UI each 15 days Group C: Calcifediol 4 drops per day. Serum levels of vitamin D are dosed after one month of treatment
Where, as registered
No US site; Italy (1).
RecruitingNCT06172764
A Randomized Controlled Trial of Vitamin D Supplementation on Salivary Biomarkers and Cariogenic Oral Microbiome
Phase 4
Dow University of Health Sciences
About 90 people
Started Dec 12, 2023
In plain words A Phase 4 study of vitamin D3 vs D2 in people 12 to 50, run by Dow University of Health Sciences. It plans to enroll about 90 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 12 to 50; healthy volunteers accepted. Conditions: Dental Caries; White Spot Lesion; Initial Caries; Incipient Enamel Caries.
Patients of all genders and ages ranging from 12-50 years, having at least two teeth with clinically diagnosed Initial Carious Lesions at Moderate Risk of Dental Caries, after written informed consent.
Patients having vitamin D deficiency.
The exclusion criteria are on the listing.
What it tests, as registered
Vitamin D supplements along with behavioral modification; Topical fluoride application and Vitamin D supplements along with behavioral modification; Topical fluoride application along with behavioral modification
Registered summary
The goal of this clinical trial is to compare the treatment effect of vitamin D supplementation and topical fluorides in the population having vitamin D deficiency and Initial Carious Lesions (ICL) on the progression of ICL in teeth. This study aims to observe the changes in the International Caries Detection and Assessment System (ICDAS) scores, the concentration of salivary proteins, and cariogenic microbes, six months after the interventions. * Group A will get vitamin D supplements and oral hygiene instructions (OHI). * Group B will get vitamin D supplements, topical fluorides, and OHI. The full summary is on the listing.
Where, as registered
No US site; Pakistan (1).
RecruitingNCT05448365
Vitamin D, Epigallocatechin Gallate, D-chiro-inositol and Vitamin B6 in Uterine Fibroid
No phase
Lo.Li.Pharma s.r.l
About 60 people
Started Jul 1, 2022
In plain words A study of vitamin D3 vs D2 in female participants 30 to 40, run by Lo.Li.Pharma s.r.l. It plans to enroll about 60 people at 2 sites, none in the US.
The study will evaluate the impact on uterine fibroids' volume of a combination of natural molecules including Epigallocatechin gallate, Vitamin D, D-chiro-inositol and Vitamin B6. The patients will be evaluated at baseline and after three months of treatment with placebo or product.
Where, as registered
No US site; Italy (2).
RecruitingNCT05787808
Profylactic Treatment for Patients in Risk Osteoporosis
No phase
Meddoc
About 60 people
Started May 2, 2023
In plain words A study of vitamin D3 vs D2 in people 55 to 85, run by Meddoc. It plans to enroll about 60 people at 1 site, none in the US.
Who it lists and where
Who the trial lists, as registered
Lists people 55 to 85; healthy volunteers accepted. Conditions: Osteopenia or Osteoporosis.
Osteopeni patients (OP) of both genders above 55 years of age. OPs are defined as patients with T-score below 0.0 but larger than -2.5.
The exclusion criteria are on the listing.
What it tests, as registered
Calsium, Vitamin D, Jarlsberg cheese
Registered summary
The aim is to compare the daily intake of Calsium (Ca) + vitamin D with and without daily optimal efficacy dose (OED) of Jarlsberg on Bone Mineral Density (BMD) and bone markers (BM) to Osteopeni patients (OP). * The study population consists of OP-patients of post-menopausal women and men above 55 years of age. OP patients are defined as patients with a T-score below 0.0, but larger than -2.5. * The study will be performed as a randomized, single-blinded Norwegian multicentre trial with stratified semi-cross-over design with gender and site as stratification factors. The full summary is on the listing.
Where, as registered
No US site; Norway (1).
ClinicalTrials.gov lists 261 open registrations for this search, including ones where vitamin D3 vs D2 is not a study arm or that are past the 40 we keep. Search them on ClinicalTrials.gov (opens in new tab).