Acute Vitamin D Supplementation on Testosterone in Females

NCT06610968 | Active Not Recruiting

• 1 other identifier: HS-24-00403
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

Participation will take place over two visits to the Clinical Exercise Research Center (CERC) at the University of Southern California Health Sciences Campus. On the first visit, height, weight, and body composition by bioelectrical impedance are recorded. Questionnaires and withdrawal of a sample of blood (1 tablespoon) are also completed. The intervention begins the day following the first visit. The intervention protocol consists of three weeks of consuming either a placebo capsule or a 5000 IU Vitamin D capsule daily and completing a daily survey. The second visit to CERC immediately follows the 3-weeks intervention. In this visit, the same blood sampling protocol will be completed. The assignment of the intervention will be randomized (i.e., rolling a die), and participants are blinded to group assignment.

Conditions

Female Hormone Profile

Outcome Measures

Primary Outcomes (4)

• Hormonal Effects of Vitamin D in Young, Healthy Women

  The primary objective is to evaluate the effect of acute Vitamin D supplementation on systemic Vitamin D, testosterone, and sex hormone modulators in pre-menopausal, healthy females. Circulating testosterone (total testosterone and free testosterone) concentrations (ng/dL) will be assessed via serum pre- and post-Vitamin D intervention.

  3 weeks

• Hormonal Effects of Vitamin D in Young, Healthy Women

  The primary objective is to evaluate the effect of acute Vitamin D supplementation on systemic Vitamin D, testosterone, and sex hormone modulators in pre-menopausal, healthy females. Circulating Vitamin D \[25(OH)D\] concentrations (ng/dL) will be assessed via serum pre- and post-Vitamin D intervention.

  3 weeks

• Hormonal Effects of Vitamin D in Young, Healthy Women

  The primary objective is to evaluate the effect of acute Vitamin D supplementation on systemic Vitamin D, testosterone, and sex hormone modulators in pre-menopausal, healthy females. Circulating gonadotropins (LH and FSH) concentrations (IU/L) will be assessed via serum pre- and post-Vitamin D intervention.

  3 weeks

• Hormonal Effects of Vitamin D in Young, Healthy Women

  The primary objective is to evaluate the effect of acute Vitamin D supplementation on systemic Vitamin D, testosterone, and sex hormone modulators in pre-menopausal, healthy females. Circulating SHBG concentrations (nmol/L) will be assessed via serum pre- and post-Vitamin D intervention.

  3 weeks

Secondary Outcomes (2)

• Effects of Body Composition on Hormonal Changes Due to Vitamin D Supplementation in Young, Healthy Women

  3 weeks

• Effects of Body Composition on Hormonal Changes Due to Vitamin D Supplementation in Young, Healthy Women

  3 weeks

Study Arms (2)

Vitamin D Group

EXPERIMENTAL

The treatment intervention will consist of three weeks of one 5000 IU cholecalciferol capsule (Pure Encapsulations, LLC) daily, with breakfast.

Dietary Supplement: Vitamin D (Cholecalciferol )

Placebo Group

PLACEBO COMPARATOR

The control group will also take a daily, with breakfast, placebo capsule (Zeebo) for the three-week intervention.

Dietary Supplement: Placebo Group

Interventions

Vitamin D (Cholecalciferol ) DIETARY_SUPPLEMENT

5000 IU Vitamin D (as cholecalciferol) capsules (Vitamin D3 125 mcg \[5,000 IU\], Pure Encapsulation, LLC) daily

Also known as: 5000 IU Vitamin D daily

Vitamin D Group

Placebo Group DIETARY_SUPPLEMENT

One placebo capsule (Zeebo Imagine, Zeebo) daily.

Also known as: Placebo (Zeebo) pill daily

Placebo Group

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Assigned female at birth
• to 35 years of age
• No chronic diseases affecting the uptake of Vitamin D or causing Vitamin D sensitivity (e.g., sarcoidosis, tuberculosis, Wegener's granulomatosis, other forms of vasculitis, inflammatory bowel diseases, etc.) \[21\]
• Completion and signature of the informed consent document
• Non-pregnant or trying to become pregnant
• No supplementation with Vitamin D within three months of enrollment
• No documented gynecological disease (e.g., PCOS, endometriosis, etc.)
• Weight greater than or equal to 110 lbs

You may not qualify if:

• Pregnant
• Supplementation with Vitamin D within three months of enrollment
• Taking exogenous hormones
• Documented gynecological disease (e.g., PCOS, endometriosis, etc.)
• Suffering from chronic diseases affecting the uptake of Vitamin D or causing Vitamin D sensitivity (e.g., sarcoidosis, tuberculosis, Wegener's granulomatosis, other forms of vasculitis, inflammatory bowel diseases, etc.) \[21\]
• Weight less than 110 lbs

Sponsors & Collaborators

• University of Southern California: lead

Study Sites (1)

University of Southern California Health Sciences Campus Center for Health Professions

Los Angeles, California, 90033, United States

Location

Related Publications (1)

• Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann A. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res. 2011 Mar;43(3):223-5. doi: 10.1055/s-0030-1269854. Epub 2010 Dec 10.

  PMID: 21154195 BACKGROUND

MeSH Terms

Interventions

Cholecalciferol

Intervention Hierarchy (Ancestors)

Cholestenes; Cholestanes; Steroids; Fused-Ring Compounds; Polycyclic Compounds; Sterols; Vitamin D; Secosteroids; Membrane Lipids; Lipids

Study Officials

• Giuliet L Kibler

  University of Southern California - Division of Biokinesiology and Physical Therapy

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Single blinded intervention. Those measuring the blood samples' hormonal will also be blinded to the intervention group but will not have a role in data analysis.
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Participants will be randomized to either a treatment or control group upon enrollment and blinded to group assignment. The treatment intervention will consist of three weeks of one 5000 IU cholecalciferol capsule (Pure Encapsulations, LLC) daily, with breakfast. The control group will also take a daily, with breakfast, placebo capsule (Zeebo) for the three-week intervention.

Study Record Dates

• First Submitted: September 17, 2024
• First Posted: September 24, 2024
• Study Start: July 1, 2025
• Primary Completion: March 5, 2026
• Study Completion (Estimated): September 30, 2026
• Last Updated: March 25, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)