Which hormone signals the body to increase protein synthesis in response to hypertrophy training?

Insulin-like growth factor-1 (IGF-1) plays a crucial role in promoting protein synthesis in response to hypertrophy training. When the body undergoes resistance training, muscle tissue experiences stress and damage, which activates a signaling cascade that leads to the release of IGF-1. This hormone is primarily produced in the liver and its production is stimulated by growth hormone.

IGF-1 works to enhance muscle growth and repair by encouraging the uptake of amino acids into muscle cells and facilitating the building of new proteins. This process is essential for muscle hypertrophy, as it supports the adaptation of muscle fibers to the stress induced by exercise. Elevated levels of IGF-1 signal the body to increase both the synthesis of muscle proteins and the proliferation of satellite cells, which are vital for muscle repair and growth.

While other hormones like insulin and testosterone also contribute to muscle growth, IGF-1 is particularly significant in the context of hypertrophy as it directly promotes the anabolic processes required for muscle adaptation. Cortisol, on the other hand, is a catabolic hormone that can counteract the effects of muscle growth when present in high levels, especially during prolonged stress or overtraining.

Thus, IGF-1 is the hormone that specifically signals