Hormones play a vital role in muscle building by regulating processes such as protein synthesis and muscle repair. Key hormones like testosterone, growth hormone, and insulin are crucial for promoting muscle growth. Testosterone enhances muscle mass by stimulating protein synthesis, while growth hormone supports tissue growth and recovery. Insulin aids in nutrient uptake, ensuring muscles receive the necessary building blocks for growth. Optimal hormone balance can enhance exercise performance and recovery, making it essential for anyone looking to build muscle effectively.