Anserine is a dipeptide containing β-alanine and histidine, which can be found in the skeletal muscle and brain of mammals and birds.?

3-Hydroxybutyric acid (or beta-hydroxybutyrate) is a ketone body. Like the other ketone bodies (acetoacetate and acetone) levels of 3-hydroxybutyrate in blood and urine are raised in ketosis. In humans 3-hydroxybutyrate is synthesized in the liver from acetyl-CoA and can be used as an energy source by the brain when blood glucose is low.

L-Kynurenine is a key intermediate in the breakdown pathway of tryptophan. L-Kynurenine is a substrate of kynureninase KMO and KAT associated with the suppression of antitumor immune responses.