Figure 2. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Flow Diagram Showing the Selection Process of Reviewed Articles.

Defined reasons reports were excluded: Reason one, non-human study; Reason two, participant age < 18; Reason three, intervention without exogenous testosterone; Reason four, participants without spinal cord injury or traumatic brain injury; Reason five, study not published in a peer-reviewed journal with full text available; Reason six, case reports, reviews, or perspectives; Reason seven, non-defined outcome measure(s).