The biologically most active, naturally occurring androgen is

• A. DHEA
• B. Androstenedione
• C. Epiandrosterone
• D. Testosterone

Answer: (D)

Testosterone is the principal circulating androgen and drives most of the androgenic effects in the body. It is produced directly by the testes and acts by binding to androgen receptors to regulate gene expression, supporting male characteristics, muscle maintenance, and reproductive functions. The other substances listed are largely precursors or weaker metabolites: DHEA and androstenedione provide substrates for testosterone production or estrogen formation and have relatively low direct androgenic activity, while epiandrosterone is a minor metabolite with limited androgenic effect. (Note that some testosterone is locally converted to dihydrotestosterone in certain tissues, where it is more potent, but overall testosterone remains the most biologically active naturally occurring androgen among these options.)