Investigating how testosterone affects reproductive hormones in transgender men

Androgen Effects on the Reproductive Neuroendocrine Axis

Phase 4 Interventional University of California, San Diego · NCT06450405

This study is testing how testosterone therapy affects hormone levels and menstrual cycles in transgender men compared to cisgender women with regular cycles.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment60 (estimated)
Ages18 Years to 35 Years
SexFemale
SponsorUniversity of California, San Diego Academic / other
Drugs / interventionsradiation
Locations1 site (San Diego, California)
Trial IDNCT06450405 on ClinicalTrials.gov

What this trial studies

This research examines the impact of testosterone replacement therapy (TRT) on the reproductive neuroendocrine axis in transgender men who are initiating testosterone therapy. The study will compare hormone levels and menstrual cycle regularity in transgender men before and during TRT with those of cisgender females who have regular menstrual cycles. Blood samples will be collected to assess reproductive hormone secretion, and participants will undergo clinical evaluations and ultrasounds throughout the study. The goal is to understand the mechanisms behind menstrual irregularities observed in transgender men receiving TRT.

Who should consider this trial

Good fit: Ideal candidates include transgender or non-binary individuals aged 18-35 who are planning to initiate testosterone therapy and have a history of regular menstrual cycles.

Not a fit: Patients who are pregnant, incarcerated, or have certain endocrine diseases or cognitive impairments may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide insights into the hormonal effects of testosterone therapy, potentially improving care for transgender men.

How similar studies have performed: Other studies have explored hormonal therapies in transgender populations, but this specific investigation into the reproductive neuroendocrine axis with a focus on testosterone's effects is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria: Transgender/Non-binary Group, Initiating Testosterone Group

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Aged 18-35
* Plan to initiate testosterone therapy
* History of regular menstrual cycles (every 24-35 days) at baseline, before beginning TRT

Inclusion Criteria: Cisgender Female Group

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Aged 18-35
* Having regular menstrual cycles (every 24-35 days)

Exclusion Criteria: All

* Pregnant
* Incarcerated
* Known cognitive impairment or institutionalized
* Hemoglobin less than 11 gm/dl at screening evaluation
* Weight less than 110 pounds
* BMI \<18 or \>35
* Current endocrine disease- including untreated thyroid abnormalities, pituitary or adrenal disease, polycystic ovary syndrome, or androgen producing tumor
* Current or recent pregnancy within two months of study enrollment
* Current or recent breast feeding within two months of study enrollment
* Diabetes, or renal, liver, or heart disease
* History of oophorectomy or hysterectomy
* History of radiation or surgery involving brain structures and/or pelvis/pelvic organs
* Currently taking any medications that may affect their reproductive hormones, such as contraceptive medications, androgens, estrogens, progestins, GnRH antagonists, GnRH agonists, insulinomimetics, and metformin.
* History of prior testosterone therapy

Where this trial is running

San Diego, California

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions TransgenderismReproductive Issues
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.