EAA – Essential Amino Acid. International Protein’s EAA is an essential amino acid that helps build muscle and aids in recovery. It absorbs quickly into the bloodstream, providing your muscles with the fuel they need to perform at their best. What is EAA?. EAA is a premium quality essential amino acid supplement which has been specifically formulated to support muscle growth and recovery. It contains high levels of all the essential amino acids, including branched chain amino acids, which are important for athletes and bodybuilders. EAA helps to promote protein synthesis and reduce muscle breakdown, making it an ideal choice for those who are looking to build muscle size and strength.