Which androgen is considered the most biologically active?

• A. DHEA
• B. DHT
• C. Testosterone
• D. Estradiol

Answer: (C)

The main idea here is how strongly an androgen can activate the androgen receptor in target tissues. DHT is formed from testosterone in many tissues by the enzyme 5-alpha reductase and binds the androgen receptor with higher affinity than testosterone. This stronger binding leads to more robust receptor-driven gene expression and androgenic effects, making DHT the more potent androgen in many contexts (notably in the skin, prostate, and external genitalia). DHEA is a weak androgen and mostly serves as a precursor to more potent hormones, while estradiol is an estrogen and acts through estrogen receptors. Testosterone, while the primary circulating androgen and a precursor to both DHT and estradiol, has comparatively lower receptor potency than DHT in many tissues. Hence, dihydrotestosterone is typically regarded as the most biologically active androgen.