Cyclo(Pro-Gly) is an active metabolite of piracetam-N-phenylacetyl-L-prolylglycine (GWS-111), it shows a greater resistance to an enzymatic effect than natural neuropeptides. Cyclo-(Gly-Pro) shows cytotoxicity at the concentration of 10 umol/L, it inhibits the growth of Bacillus subtilis with the minimal inhibitory concentration (MIC) value of 0.8, 0.8 g/L.

(Arg8,des-Gly-NH29)-Vasopressin

O-Acetylserine (OASS) is an acylated amino acid derivative. It is an intermediate in the biosynthesis of the common amino acid cysteine in bacteria and plants. Its presence in humans arises from either microbial metabolism in the gut or through consumption of foods containing OASS.