Effects of Different Vitamin D3 Formulations in Vitamin D-Deficient Adults

NCT07317830 | Recruiting

• 1 other identifier: 302-27-01
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized controlled superiority pilot trial will evaluate the efficacy of two vitamin D3 formulations administered over eight weeks in adults with subclinical or clinical vitamin D deficiency. The study will compare changes in serum 25-hydroxyvitamin D concentrations between formulations, as well as the proportion of participants who will achieve vitamin D sufficiency. Both formulations are expected to improve vitamin D status, with the hypothesis that one formulation will demonstrate superior bioavailability, resulting in greater and faster increases in circulating 25-hydroxyvitamin D. The findings will provide preliminary evidence to inform formulation selection and dosing strategies for correcting vitamin D deficiency and will support the design of larger, confirmatory trials.

Conditions

Vitamin D Deficiency

Outcome Measures

Primary Outcomes (1)

• 25(OH)D

  Serum levels of 25(OH)D

  Change from baseline 25(OH)D at 8 weeks

Secondary Outcomes (4)

• Total calcium

  Change from total calcium at 8 weeks

• Ionized calcium

  Change from ionized calcium at 8 weeks

• Phosphorus

  Change from phosphorus at 8 weeks

• Magnesium

  Change from magnesium at 8 weeks

Study Arms (2)

Experimental 1

EXPERIMENTAL

2,000 IU of active ingredient (powder) per day

Dietary Supplement: Experimental 1 (powdered supplement)

Experimental 2

ACTIVE COMPARATOR

2,000 IU of active ingredient (oil) per day

Dietary Supplement: Experimental 2 (oily supplement)

Interventions

Experimental 1 (powdered supplement) DIETARY_SUPPLEMENT

Active powdered ingredient (2,000 IU/d)

Experimental 1

Experimental 2 (oily supplement) DIETARY_SUPPLEMENT

Active oily ingredient (2,000 IU/d)

Experimental 2

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 18 years and over
• Serum 25(OH)D \< 75 nmol/L
• BMI 18.5 - 29.9 kg/m2
• Free of clinically significant acute disorders and severe chronic diseases
• No planned travel to high-UV destinations or tanning bed use during the trial
• Willing to avoid non-study vitamin D supplements
• Able to give written informed consent and comply with study visits
• Submitted informed consent

You may not qualify if:

• Pregnancy of breast feeding
• Underweight or obesity
• History of any dietary supplement use within 8 weeks before screening
• Medications that materially alter vitamin D metabolism or calcium balance
• Subjects with a history of medicine or alcohol abuse
• Abnormal values for lab clinical chemistry (\> 2 SD)
• Unwillingness to return for follow-up analysis
• Participation in other clinical trials within 60 days prior to screening

Sponsors & Collaborators

• Center for Health Sciences, Serbia: lead

Study Sites (1)

Center for Health Sciences

Belgrade, 11000, Serbia

RECRUITING

Related Publications (3)

• Vieira EF, Souza S. Formulation Strategies for Improving the Stability and Bioavailability of Vitamin D-Fortified Beverages: A Review. Foods. 2022 Mar 16;11(6):847. doi: 10.3390/foods11060847.

  PMID: 35327269 BACKGROUND

• Dalek P, Drabik D, Wolczanska H, Forys A, Jagas M, Jedruchniewicz N, Przybylo M, Witkiewicz W, Langner M. Bioavailability by design - Vitamin D3 liposomal delivery vehicles. Nanomedicine. 2022 Jul;43:102552. doi: 10.1016/j.nano.2022.102552. Epub 2022 Mar 26.

  PMID: 35346834 BACKGROUND

• Borel P, Caillaud D, Cano NJ. Vitamin D bioavailability: state of the art. Crit Rev Food Sci Nutr. 2015;55(9):1193-205. doi: 10.1080/10408398.2012.688897.

  PMID: 24915331 BACKGROUND

MeSH Terms

Conditions

Vitamin D Deficiency

Condition Hierarchy (Ancestors)

Avitaminosis; Deficiency Diseases; Malnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases

Study Officials

• Sergej Ostojic, MD, PhD

  University of California, Los Angeles

  STUDY CHAIR

Central Study Contacts

Sergej Ostojic, MD, PhD

CONTACT

+381112643242; sergej.ostojic@chess.edu.rs

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 12, 2025
• First Posted: January 5, 2026
• Study Start: December 15, 2025
• Primary Completion (Estimated): May 31, 2026
• Study Completion (Estimated): June 15, 2026
• Last Updated: January 5, 2026

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: Data requests can be submitted starting 9 months after article publication and the data will be made accessible for up to 24 months. Extensions will be considered on a case-by-case basis.
• Access Criteria: Only qualified researchers with academic interest in vitamin D research

Locations

SE (1)