Arachidonic acid is a polyunsaturated fat with the chemical structure 20:4. Arachidonic acid plays an essential role in the growth and repair of skeletal muscle tissue. It is an essential dietary component in the muscle hypertrophy process.

Whenever you lift weights, the damaged muscle cells signal enzymes to flock towards the damaged tissue to free arachidonic acid from the intercellular membranes. The freed arachidonic acid is used to create localized enzymes called prostaglandins. Prostaglandins regulate in the inflammation processes that stimulates the growth of skeletal muscle cells. These are the same enzymes that cause the inflammation and pain you feel post-training.