What is the primary hormone involved in muscle growth and repair?

Testosterone plays a crucial role in muscle growth and repair, making it the primary hormone associated with these processes. It facilitates the synthesis of proteins within muscle cells, leading to muscle hypertrophy, which is an increase in the size of muscle fibers. Testosterone also enhances the production of growth factors that promote muscle recovery after exertion and damage.

Moreover, this hormone helps maintain muscle mass by reducing protein breakdown, thereby contributing to a positive balance between muscle protein synthesis and degradation. Its anabolic effects make it foundational for anyone looking to enhance their strength and muscular development through training or athletic performance.

In contrast, estrogen has a more significant role in female reproductive health and does not directly contribute to muscle growth in the same way as testosterone. Cortisol, while important for regulating metabolism and the body's stress response, is catabolic and can lead to muscle breakdown when present in excess. Insulin plays a supportive role by aiding in nutrient delivery to cells but does not directly stimulate muscle growth. Thus, testosterone is instrumental in promoting the anabolic processes vital for effective muscle development and repair.