NCT07317830

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

The Effects of Eight Weeks of Supplementation With Two Vitamin D₃ Formulations in Adults With Subclinical and Clinical Vitamin D Deficiency: A Randomized Controlled Superiority Pilot Trial

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: Center for Health Sciences, Serbia · Academic / Other
• Sex: All
• Age: 18 Years – 80 Years
• Healthy volunteers: Accepted

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

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Experimental 1 (powdered supplement)	Active powdered ingredient (2,000 IU/d)
DIETARY_SUPPLEMENT	Experimental 2 (oily supplement)	Active oily ingredient (2,000 IU/d)

Timeline

• Start date: 2025-12-15
• Primary completion: 2026-05-31
• Completion: 2026-06-15
• First posted: 2026-01-05
• Last updated: 2026-01-05

Locations

1 site across 1 country: Serbia