title: Subcutaneous Testosterone: An Effective Delivery Mechanism for Masculinizing Young Transgender Men.
abstract: OBJECTIVE
  Testosterone is the recommended treatment for transgender youth who desire the development of male secondary sexual characteristics. While intramuscular injection remains the most common means of delivering injectable testosterone, subcutaneous (SC) delivery has been used with clinical success. No data reporting serum levels and feasibility are available. We aimed to determine both if subcutaneous delivery of testosterone resulted in menstrual cessation, and the normal male ranges of serum testosterone in this subpopulation of female-to-male transgender youth.
  
  
  METHODS
  Within an urban hospital-affiliated Adolescent Medicine clinic, thirty-six youth aged 13 to 24 years transitioning from female to male received testosterone cypionate via subcutaneous injections for masculinization. Participants were a subpopulation of those enrolled in a longitudinal, prospective study examining the impact of treatment for transgender youth. A titrated dose of testosterone cypionate (average dose 46.4 mg per week) via subcutaneous injection was delivered over 6 months. The main outcomes included menstrual cessation as well as raised free and total testosterone levels.
  
  
  RESULTS
  Eighty-five percent of participants had ceased menstrual bleeding within 6 months after initiating testosterone. The average time to menstrual cessation was 2.9 months. Most participants (91.4%) reached total testosterone levels within the normal male range after 6 months of subcutaneous delivery (49-1138 ng/dL, 521.4 ng/dL total test). Few adverse effects were reported.
  
  
  CONCLUSIONS
  Subcutaneous delivery of testosterone for masculinization of transgender youth seems to be effective and well tolerated over short treatment times. Additional studies are needed to determine whether long term use of subcutaneous testosterone delivery yield similar results.
authors.affiliation: 1 Department of Adolescent Medicine, Children's Hospital Los Angeles , California.|2 Keck School of Medicine, The University of Southern California , Los Angeles, California.
authors.forename: Johanna
authors.initials: J
authors.lastname: Olson
authors.affiliation: 1 Department of Adolescent Medicine, Children's Hospital Los Angeles , California.
authors.forename: Sheree M
authors.initials: SM
authors.lastname: Schrager
authors.affiliation: 1 Department of Adolescent Medicine, Children's Hospital Los Angeles , California.|2 Keck School of Medicine, The University of Southern California , Los Angeles, California.
authors.forename: Leslie F
authors.initials: LF
authors.lastname: Clark
authors.affiliation: 3 University of California-Los Angeles , Los Angeles, California.
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Dunlap
authors.affiliation: 1 Department of Adolescent Medicine, Children's Hospital Los Angeles , California.|2 Keck School of Medicine, The University of Southern California , Los Angeles, California.
authors.forename: Marvin
authors.initials: M
authors.lastname: Belzer
keywords: masculinization; subcutaneous testosterone; transgender men; transgender youth