Active — Not RecruitingNot Applicable

Acute Vitamin D Supplementation on Testosterone in Females

United States20 participantsStarted 2025-07-01

Plain-language 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.

Who can participate

Age range

18 Years – 35 Years

Sex

FEMALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Assigned female at birth * 18 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 Exclusion Criteria: * 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

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Hormonal Effects of Vitamin D in Young, Healthy Women

Timeframe: 3 weeks

Hormonal Effects of Vitamin D in Young, Healthy Women

Timeframe: 3 weeks

Hormonal Effects of Vitamin D in Young, Healthy Women

Timeframe: 3 weeks

Hormonal Effects of Vitamin D in Young, Healthy Women

Timeframe: 3 weeks

Trial details

NCT IDNCT06610968

SponsorUniversity of Southern California

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2026-03-05

View on ClinicalTrials.gov More Female Hormone Profile trials

Plain-language summary

Who can participate

Age range

18 Years – 35 Years

Sex

FEMALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.