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Home › Conditions › Vitamin D deficiency

Vitamin D deficiency

Part of Malnutrition

4 published articles · Updated continuously

Clinical Trial Landscape

Clinical Trials for Vitamin D deficiency

69 trials tracked for Vitamin D deficiency: 25 in phase 3 or 4 and 8 with published results. The most-cited published study has 846 citations.

69Trials tracked
25Phase 3 & 4
0Recruiting
8With published results
Phase distribution
Phase 4 12 Phase 3 13 Phase 2 12 Phase 1 2 Other / NA 30
  1. Phase 3 Evaluation of Vitamin D Requirements During Pregnancy Completed · 846 cited
  2. Phase 3 Vitamin D to Improve Outcomes by Leveraging Early Treatment Completed · 305 cited
  3. Phase 4 The Effects of Vitamin D on Angiogenic Factors in Women With Polycystic Ovary Syndrome Completed · 114 cited
  4. Phase 3 Vitamin D Status of Pregnant Women and Their Children in Eau Claire, South Carolina Completed · 104 cited
  5. Phase 3 Establishing the Vitamin D Requirements During Lactation Completed · 69 cited
  6. Phase 4 Treatment Study of Vitamin D Deficiency in Adolescents Completed · 25 cited
Show 44 more trials
  1. Phase 3 Hypovitaminosis D in Neurocritical Patients Completed · 22 cited
  2. Phase 4 Vitamin D and Coronary Calcification Study Completed · 12 cited
  3. Phase 4 Vitamin D Repletion in Primary Hyperparathyroidism Completed
  4. Phase 4 Vitamin D Increases Serum Levels of the Soluble Receptor for Advanced Glycation End Products in Women With PCOS Completed
  5. Phase 4 Can Vitamin D Reduce Heart Muscle Damage After Bypass Surgery? Completed
  6. Phase 4 Vitamin Deficiency in Immigrants, a Treatment Study Completed
  7. Phase 4 Efficacy of Vitamin D2 to Treat Chronic Kidney Disease Mineral and Bone Disorder Completed
  8. Phase 4 Does Treatment of Hypovitaminosis D Increase Calcium Absorption? Completed
  9. Phase 4 Treatment of Vitamin D Insufficiency Completed
  10. Phase 4 Effect of Omega-3 Fatty Acid on Vitamin D Activation Completed
  11. Phase 4 Vitamin D Repletion in Stone Formers With Hypercalciuria Completed
  12. Phase 3 Safety and Efficacy of CTAP101 to Treat Secondary Hyperparathyroidism in Stage 3 or 4 CKD and Vitamin D Insufficiency Completed
  13. Phase 3 Safety and Efficacy of CTAP101 to Treat Secondary Hyperparathyroidism in Stage 3 or 4 CKD and Vitamin D Insufficiency Completed
  14. Phase 3 Extension Study of CTAP101-CL-3001 or CTAP101-CL-3002 Completed
  15. Phase 3 Improving the Understanding of the Response to Vitamin D Supplementation Completed
  16. Phase 3 Vitamin D in Vulnerable Adults (VIVA-VA) Completed
  17. Phase 3 Effect of Vitamin D Treatment in Primary Hyperparathyroidism Completed
  18. Phase 3 Safety of Vitamin D Supplementation in Older Persons Completed
  19. Phase 3 Controlled Trial of Prenatal Vitamin D3 Supplementation to Prevent Vitamin D Deficiency in Mothers and Their Infants Completed
  20. Phase 2 Vitamin D Supplementation in RNA-seq Profiles of Single-core Prostate Samples, Among Veterans Completed
  21. Phase 2 Prevention of Vitamin D Deficiency Following Pediatric CHD Surgery: a Phase II Dose Evaluation Randomized Controlled Trial Comparing Usual Care With a High Dose Pre-operative Supplementation Regimen Based on the Institute of Medicine Daily Upper Tolerable Intake Level Completed
  22. Phase 2 Study of Vitamin D and Effect on Heart Disease and Insulin Resistance Completed
  23. Phase 2 Safety, Efficacy, and Feasibility of High-dose Cholecalciferol in Pediatric Patients With Cystic Fibrosis Completed
  24. Phase 2 Daily Vitamin D for Sickle-cell Respiratory Complications Completed
  25. Phase 2 Effect of Vitamin D3 Supplementation in Pregnancy on Risk of Pre-eclampsia Completed
  26. Phase 2 Blue Sky Study: Impact of Milk and Vitamin D for Child Growth and Health Completed
  27. Phase 2 Topical Delivery of Vitamin D3 as Vitamin D Supplementation Completed
  28. Phase 2 Vitamin D for Sickle-cell Respiratory Complications Completed
  29. Phase 2 Correction of Vitamin D Levels and Its Effect on Insulin Resistance and Weight Gain in Obese Youth Completed
  30. Phase 2 Blood Pressure in Blacks and Calcium (BBC) and Vitamin D Study Completed
  31. Phase 2 Nutrition and Body Composition in Acute Lymphoblastic Leukemia Completed
  32. Phase 1 Human Pharmacology Trial of Calcium-vitamin D3 Tablet in Healthy Participants Completed
  33. Phase 1 Effect of Vitamin D Supplementation on Endothelial Function in Obese Adolescents Completed
  34. N/A Cholecalciferol in Newly Diagnosed Non-Hodgkin Lymphoma or Chronic Lymphocytic Leukemia With Vitamin D Deficiency Completed
  35. N/A Vitamin D Supplementation in Kidney Disease Completed
  36. N/A Vitamin D Supplementation in Psychiatric Illnesses Completed
  37. N/A Vitamin D and Vascular Health in Children Completed
  38. N/A Incidence of HANA Conditions in HIV-infected Individuals Completed
  39. N/A Treatment of Vitamin D Deficiency in Intestinal Rehabilitation Clinic Patients With a Portable Ultraviolet B Lamp Completed
  40. N/A Effect of Vitamin D3 on Vascular Function Completed
  41. N/A Cholecalciferol (Vitamin D3) Therapy in Chronic Kidney Disease (CKD) Subjects Completed
  42. N/A Vitamin D in HIV-Infected Patients on HAART Completed
  43. N/A hCAP18 Levels and Vitamin D Deficiency in Healthy Subjects Completed
  44. N/A Vitamin D Replacement After Kidney Transplant Completed

Showing the 50 most-cited and recently-updated of 69 trials. Browse the full registry →

Trial data sourced from ClinicalTrials.gov. Counts describe the research landscape and are not a treatment recommendation. Informational only — not medical advice.

What the trials found Updated — new results For clinicians

Vitamin D deficiency: what the trials found

Several trials evaluated vitamin D and its derivatives, including cholecalciferol (Vitamin D3), ergocalciferol, and Vitamin D2, across various clinical contexts. High-dose cholecalciferol was shown to significantly increase serum vitamin D levels in patients with deficiency 5. Additionally, specific interventions like CTAP101 30 μg capsules were found to significantly decrease plasma intact parathyroid hormone (iPTH) by ≥30% from baseline and increase the number of subjects with normal serum total 25-hydroxyvitamin D [21, 22].

Clinical outcomes for vitamin D interventions showed mixed results in acute settings. In a trial involving cholecalciferol, there was no statistically significant difference in all-cause mortality to day 90 (p=0.26), ventilator-free days, or cardiovascular SOFA scores 15. Another study on cholecalciferol reported no significant differences in hospital length of stay or ICU length of stay 18. Regarding metabolic markers, Vitamin D2 was associated with significantly lower phosphorus levels at 24 months (p<0.001), while changes in calcium and intact parathyroid hormone were not statistically significant 9.

Specific physiological measurements showed varied results: cholecalciferol was associated with a reduction in Caspase 3 enzyme levels and blood units usage 6, and vitamin D administration resulted in a negligible change in Short Physical Performance Battery Test scores 19. One study noted an increase in 25-hydroxyvitamin D levels and hemoglobin levels following omega-3 fatty acid ethylester supplementation 11.

Newer data indicate that cholecalciferol (Vitamin D3) can significantly improve 25-hydroxyvitamin D levels in postpartum mothers over a 7-month period 17.

Recent results — preliminary, needs further review

  • Cholecalciferol showed significant increases in serum vitamin D and end-of-treatment vitamin D levels in deficient patients (p=0.001) 5.
  • CTAP101 30 μg capsules significantly increased the proportion of patients with normal 25-hydroxyvitamin D and reduced iPTH levels (p<0.0001) [21, 22].

For the clinician treating this condition

  • High-dose cholecalciferol is effective for increasing serum vitamin D in patients with confirmed deficiency 5.
  • CTAP101 30 μg capsules are highly effective at normalizing serum 25-hydroxyvitamin D and reducing intact parathyroid hormone (iPTH) levels [21, 22].
  • Vitamin D interventions do not consistently demonstrate significant improvements in mortality or length of stay in acute clinical settings based on the available data [15, 18].

AI synthesis of 8 cited trials, updated Jun 29, 2026. Informational only — not medical advice; trial data sourced from ClinicalTrials.gov. How we use AI.

HCP Mode — summaries include clinical detail, trial data, and statistical outcomes.
Patient Mode — summaries use plain language, avoiding clinical jargon.
Routine vitamin D testing in Saudi Arabia shows nearly half of patients have deficiency levels
Drug Pipeline Cohort
Routine vitamin D testing in Saudi Arabia shows nearly half of patients have deficiency levels Half of patients tested for vitamin D levels were found to be deficient
This retrospective cross-sectional analysis evaluated serum 25-hydroxyvitamin D concentrations in 14,369 patients at a Saudi hospital.
A large analysis of routine tests shows nearly half of patients had low vitamin D, highlighting a widespread need for better public health m…
Frontiers Apr 29, 2026
Pre-diagnostic vitamin D deficiency linked to higher thyroid cancer risk in a large retrospective cohort
Nutrition & Obesity Medicine Cohort
Pre-diagnostic vitamin D deficiency linked to higher thyroid cancer risk in a large retrospective cohort Could low vitamin D before diagnosis raise your risk of developing thyroid cancer?
This retrospective propensity score–matched cohort study analyzed adults aged ≥ 18 y with serum 25-hydroxyvitamin D measurements within the …
Low vitamin D levels before a thyroid cancer diagnosis are linked to a higher risk of developing the disease over ten years, according to ne…
Frontiers Apr 21, 2026
Vitamin D deficiency associated with depression in adolescents and young adults, stronger in females
Psychiatry Meta-analysis
Vitamin D deficiency associated with depression in adolescents and young adults, stronger in females Vitamin D deficiency linked to depression in adolescents and young adults, especially females
A systematic review and meta-analysis of 27,956 adolescents and young adults found vitamin D deficiency (<50 nmol/L) was associated with dep…
Young people with low vitamin D levels are twice as likely to have depression, a link that is especially strong in females.
medRxiv Apr 4, 2026
Vitamin D3 supplementation improved exercise tolerance in deficient male COPD patients in small RCT
Pulmonology & Critical Care RCT
Vitamin D3 supplementation improved exercise tolerance in deficient male COPD patients in small RCT Vitamin D supplements linked to better walking ability in men with COPD and low vitamin D
A 26-week double-blind RCT in 40 vitamin D3-deficient male COPD patients found that oral vitamin D3 supplementation (80,000 IU/week then adj…
Men with COPD and low vitamin D levels walked farther and felt less breathless after taking supplements for six months.
Apr 2, 2026

Research across Malnutrition

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Questions about Vitamin D deficiency

Why are the effects of Vitamin D deficiency on depression stronger in females?

Research shows that low Vitamin D levels are linked to a higher risk of depression in women compared to men, with studies finding stronger associations specifically in female populations.

Full answer →