What does science say about Vitamin D and cancer (all types)?
- We don’t say yes or no. We show what has been studied.
- Working in a lab or in animals does not mean it works in people.
- Don’t stop or change your treatment without talking to your doctor.
What has been studied
- Lab studies (cells)Tests on cells in a dish.Source: PubMed · as of 11 Nov 2026 · Open the search at PubMed638studies
- Animal studiesTests in mice, rats or other animals.Source: PubMed · as of 11 Nov 2026 · Open the search at PubMed513studies
- Studies in peoplePublished studies with human participants.Source: PubMed · as of 11 Nov 2026 · Open the search at PubMed1701studies
- Registered trials in peopleTrials entered in a public registry, whatever their result.ClinicalTrials.gov: 23 · as of 11 Nov 2026 · Open the search at ClinicalTrials.govEU CTIS: 1 · as of 11 Nov 2026 · Open the search at EU CTISBy phase:No phase (8)Phase 3 (7)Phase 2 (4)Early Phase 1 (3)Phase 4 (2)By status:Recruiting (11)Completed (6)Not yet recruiting (4)Running, not recruiting (2)By invitation only (1)Countries (12):United States (11)Spain (2)Canada (1)Colombia (1)Germany (1)Egypt (1)France (1)Italy (1)Nigeria (1)Puerto Rico (1)Serbia (1)Russia (1)With a linked publication (results): 2 of 24The registries do not tell us here whether results were posted; a linked publication is shown instead.24trials
- Approved treatmentApproved by a medicines regulator for this disease.No
Cancer here means all 33 cancer types we cover.
Examples of what we found
The trials
Phase 3
Comparative Analysis of Immunological Responses to Vitamin D Replacement Therapy in Black and West African Men Diagnosed With Prostate Cancer: Elucidating Differential Effects on Immune Function Between Patients With Localized Disease and Those With Metastatic Progression
Not yet recruiting · Nigeria
ClinicalTrials.gov · NCT07598032No phase
Immunonutrition for Surgical Prehabilitation of Patients With Upper GI Cancer
By invitation only · Spain
ClinicalTrials.gov · NCT07884214No phase
Vitamin D Status and Clinical Outcomes in Locally Advanced Cervical Cancer
Recruiting · Serbia
ClinicalTrials.gov · NCT07743918Early Phase 1
VitD3 Supplementation in Patients With Multiple Myeloma
Recruiting · United States
ClinicalTrials.gov · NCT05846880Phase 2
Vitamin A and D Supplementation in Allogeneic HCT
Recruiting · Russia
ClinicalTrials.gov · NCT06508099Phase 3
Vitamin D for Prostate Endocrine Therapy
Recruiting · United States
ClinicalTrials.gov · NCT05838716Early Phase 1
Immunological Effects of Vitamin D Replacement Among Black/African American Prostate Cancer Patients
Recruiting · United States
ClinicalTrials.gov · NCT05045066Phase 3
Vitamin D3 With Chemotherapy and Bevacizumab in Treating Patients With Advanced or Metastatic Colorectal Cancer
Running, not recruiting · Puerto Rico, United States
ClinicalTrials.gov · NCT04094688Early Phase 1
Vitamin D in Patients With Stage I-III Colon Cancer or Resectable Colon Cancer Liver Metastases
Recruiting · United States
ClinicalTrials.gov · NCT02172651No phase
Cholecalciferol in Improving Survival in Patients With Newly Diagnosed Cancer With Vitamin D Insufficiency
Running, not recruiting · United States
ClinicalTrials.gov · NCT01787409Phase 3
A Study to Evaluate the Effect of Vitamin D on PFS in Indolent Non-Hodgkin's Lymphoma
Completed · United States
ClinicalTrials.gov · NCT03078855
Thinking of paying for it? Read this first
- Ask for published results. Stories, thank-you letters and "patients report" are not results. Ask where the results were published.
- Know what you pay for. Ask in writing: what exactly is included, who gets the money, and what happens if you stop.
- Ask your own doctor first. Some products interfere with chemotherapy, radiation or other medicines. Your treating doctor can check this.
- Do not stop standard treatment for it. Do not stop or delay your treatment without talking to your care team.
Not medical advice. Talk to the care team before changing treatment.