Leucine, isoleucine and valine are essential amino acids which are not produced by the body and must be ingested from the diet.They are found in large amount in muscles of meat and are necessary for synthesis of proteins in the body.They are wasted during liver disorders, high catabolic processes (cancer, burns) and also used for dietary supplementation in sport and fitness. At latest update no published data on excretion into breast milk were found.Around 20 amino acids (8 of them are essential) are normally present in breastmilk to which they reach through a selective-transport system of alveolar mammary epithelium (Ramirez 2001) with higher concentrations observed in the milk of obese mothers ( De Luca 2016).Its concentration is higher in the plasma of both mother and newborn after vaginal delivery than after cesarean section. (Schulpis 2009).BCAA supplementation does not alter the levels of prolactin (Bianchi 1992). These are natural components of the body that are devoid of toxicity even at higher doses than those recommended (AESAN 2012) without harmful effect while breastfeeding.