Nordihydroguaiaretic acid (NDGA) is a phenolic antioxidant found in the leaves and twigs of the evergreen desert shrub, Larrea tridentata (Sesse and Moc. ex DC) Coville (creosote bush).

N-Acetyl-L-phenylalanine is an essential amino acid produced for medical feed and nutritional applications. It appears in large amount in urine of patients with phenylketonuria which is a human genetic disorder due to the lack of phenylalanine hydroxylase the enzyme necessary to metabolize phenylalanine to tyrosine.

Formiminoglutamic acid (NSC 334078) is a biomarker for formylaminoglutaminuria, an indicator of folate deficiency.