Could you tell me more about how testosterone affects the body in general?

Testosterone is a hormone with broad effects on reproductive function, physical development, motivation, stress responses, and behavior. Its effects depend on the person and context; it does not simply create aggression or any single behavior. 1 2

• Libido, aggression, and competition: Testosterone is associated with increased libido and willingness to compete. It can amplify tendencies or responses already present rather than automatically causing aggression; how aggression is expressed depends on context and the brain pathways involved. 3 4
• Stress, effort, and pain: By lowering anxiety or stress thresholds, testosterone may make people more willing to persist, tolerate effort, and pursue goals; Huberman also describes effort as feeling rewarding. 5 6
• Physical development and performance: Testosterone supports muscle and bone development and contributes to traits such as a deeper voice and facial hair; some effects involve its conversion to DHT. It can also increase motivation and energy, and is discussed in relation to muscle and other tissue adaptation. 7 8 9
• Sperm production: In men, testosterone made in the testes works alongside other testicular signals and proteins to support sperm production. 10
• Fatherhood: Testosterone levels can fall in expecting fathers, alongside hormonal changes that Huberman connects with the transition to parenthood. 11
• Recovery, muscle synthesis, and competitiveness: Testosterone can influence muscle, tendon, ligament, and bone adaptation; the cited discussion also describes training conditions used to stimulate testosterone and anabolic responses. Higher testosterone is linked with greater competitive effort and reproductive access in some animal species. 12 13 14