Lignoceric Acid (tetracosanoic acid) is a saturated fatty acid with a 24-carbon backbone, that occurs naturally in wood tar, various cerebrosides, and in small amount in most natural fats. In mammals, it is found in cerebrosides and is synthesized during brain development. The deficient peroxisomal oxidation of very-long-chain fatty acids, including lignoceric acid, contributes to certain syndromes, including Zellweger cerebro-hepato-renal syndrome and X chromosome-linked adrenoleukodystrophy. Lignoceric acid is also a product of lignin production.

EC23, also known as AGN 190205, is photostable synthetic analog of All-trans retinoic acid (ATRA). EC23 is an agonist of retinoic acid receptors: alpha, beta and gamma, while having no appreciable activity for retinoid X receptors and weakly activates aryl hydrocarbon receptor. It was shown, that EC23 induced neural differentiation in human pluripotent embryonic stem cells.

DL-5-hydroxytryptophan, 5-HTP is a serotonin precursor. It was discovered on the rats, that the pharmacological responses and changes in brain 5-hydroxytryptamine (5-HT) concentration elicited following the administration of 5-HTP did not reflect changes in the concentration of endogenous brain 5-HT. The biochemical and pharmacological properties of the 5-HTP-induced increases in brain 5-HT concentration were distinctly different from those of increases in the endogenous content of the amine. In normal rats, administered 5-HTP, observable pharmacological responses were not elicited, despite equal or even larger increases in brain 5-HT concentration.

3-Tyrosine, in contrast to the para isomer, is readily racemized. The majority of the load was metabolized to m-hydroxyphenylacetic acid but m-hydroxymandelic acid and 3,4-dihydroxyphenylacetic acid were also detected. Low circulating levels of m-tyrosine in the plasma suggest that most of the load is held due to a first pass effect somewhere in the enterohepatic system and that this portion of the load is not in equilibrium with the plasma m-tyrosine. The metabolism of a m-tyrosine may give further insight into the deficiencies of the phenylalanine hydroxylating system found in the various phenotypes of phenylketonuria. 3-Tyrosine has been used experimentally as a substitute for L-DOPA in the treatment of Parkinsonism. 3-tyrosine mimics the action of Dopa in two experimental animal models. It was also obvious from the experiments with d,l- and l-m-tyrosine that only the l-isomer (3-Tyrosine) is active.