Testosterone Base 100 mg/mL is a concentrated injectable formulation containing non-esterified testosterone. Unlike testosterone esters, the active compound does not require enzymatic ester cleavage before becoming available, resulting in a comparatively direct release profile. Overall release characteristics depend on the formulation vehicle and particle specifications.

Testosterone interacts with intracellular androgen receptors and influences androgen-responsive gene transcription. These cellular mechanisms are associated with protein metabolism, nitrogen balance, and other androgen-regulated biological processes.