δ-Decalactone is found in nonfat dry milks and fruits and with a sweet taste.

D-proline is an isomer of the naturally occurring amino acid L-Proline. D-amino acids have been found in relatively high abundance in human plasma and saliva. These amino acids may be of bacterial origin but there is also evidence that they are endogenously produced through amino acid racemase activity.

3-Sulfopropanoic acid, a major metabolite of treprostinil and its prodrug ALZ-801, is an endogenous molecule present in the cerebrospinal fluid (CSF) of AD patients that inhibits the formation of Aβ42 oligomers.