Itaconic acid also known as itaconate belongs to the class of organic compounds known as branched fatty acids. These are fatty acids containing a branched chain. Itaconic acid exists as a solid soluble (in water) and a weakly acidic compound (based on its pKa). Itaconic acid has been detected in multiple biofluids such as sweat and urine.

4-Guanidinobutyric acid is an L-arginine metabolite that has been used in the intestinal transport tranport studies. It has been specifically use to human proton coupled amino acid transporters hPAT1.

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.