There is evidence that mother's own milk is the best nutrient in terms of multiorgan protection and infection prevention. However, when maternal milk is scarce, the solution can be represented by donor milk (DM), which requires specific storage procedures such as Holder Pasteurization (HoP). HoP is not free from side effects since it is widely known that it causes qualitative/quantitative changes in milk composition, particularly in the protein content. Therefore, the aim of this study is to investigate the effects of HoP on Activin A, a neurobiomarker known to play an important role in the development and protection of the central nervous system.In 24 mothers who delivered preterm (n = 12) and term (n = 12) healthy newborns, we conducted a pretest/test study where the milk donors acted as their own controls. Each sample was divided into two parts: the first was frozen at -80°C (Group 1); the second was Holder-pasteurized before freezing at -80°C (Group 2). Activin A was quantified using an ELISA test.Activin A was detected in all samples. There were no significant differences (p > 0.05) between the two groups, also when the analysis was stratified for gestational age at delivery and milk maturation degree (p > 0.05, for both).The present findings on the absence of any side effects of HoP on the milk concentration of Activin A offer additional support to the efficacy of HoP in DM storage. Our data open up to further investigations on neurobiomarkers' assessment in human milk and their preanalytical stability according to storage procedures.