2. Sexual characteristic
3. Sexual function, spermatogenesis, fertility
4. Bone health | Aromatized into estrogen, contribute to breast formation |

Types of testosterone

• TT - Total Testosterone
  • Bio-available T
  • SHBG-bound T

Function (Main: testicular; Minor: adrenal)

1. Internal and external genitalia
2. male secondary sexual characteristic
3. sexual function, spermatogenesis & fertility
4. Bone health

• Fetal development: 1
• Puberty: induction of 2,3
• Adulthood: maintaining 2,3

Total Testosterone decreases with age.