The natural tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP also known as Goralatide) is generated from the N-terminus of thymosin-β4 through enzymatic cleavage by prolyl oligopeptidase (POP). AcSDKP regulation of proliferation of different cells is implicated in hematopoiesis and angiogenesis. This tetrapeptide present in almost all cells was recently detected at elevated concentrations in neoplastic diseases. However, previously reported in vitro and in vivo studies indicate that AcSDKP does not contribute to the pathogenesis of cancers. AcSDKP was in the phase II clinical trial for development of a new non-radioactive test for measuring glomerular filtration rate in patient with Chronic Kidney Disease. In addition, using mice models was concluded ,that AcSDKP might be an oral antifibrotic peptide drug that would be relevant to combating fibroproliferative kidney diseases such as diabetic nephropathy.