What is EAA (Essential Amino Acids)? Amino acids are the building blocks of protein, which helps to promote the growth and maintenance of muscle. Essential amino acids are the amino acids that your body needs but cannot produce on its own. You can only get them through your diet by eating things like meat or eggs, or taking a convenient supplement like this one. There are nine essential amino acids in total three branched chain amino acids (BCAAs) and six other essential amino acids. Reflexs EAAs gives you 16g of EAAs per serving making it a premium source of essential amino acids to promote muscle growth. Research has shown EAAs to; prevent muscle fatigue during a resistance training session (1), improve lean body mass (2), and assist with muscle growth (3).