Skeletal muscle is in a near constant state of buildup and breakdown. Hormones, muscle tension, nutrients end genes play critical roles in determining whether muscles get larger, smaller or stay the same size. Corticosteroids, stress hormones
produced in the adrenal glands, and the myostatin gene stimulate muscle breakdown, while testosterone, growth hormone and IGF-1 stimulate muscle growth.
Researchers from the Charles R. Drew University of Medicine and Science in Los Angeles, in a study on rats, found that glutamine supplements prevented muscle atrophy (decrease in muscle size) triggered by glucocorticoids by suppressing the myostatin gene. This gene prevents muscle growth and promotes muscle atrophy. Intense bodybuilding training stimulates glucocorticoid release, which promotes muscle break down. Glutamine supplements may help you recover more quickly and increase muscle size faster by preventing muscle breakdown after training and promoting muscle hypertrophy.