3-hydroxybutyric acid is involved in the synthesis and degradation of ketone bodies. Like the other ketone bodies (acetoacetate and acetone) levels of beta-hydroxybutyrate are raised in the blood and urine in ketosis. Beta-hydroxybutyrate is a typical partial-degradation product of branched-chain amino acids (primarily valine) released from muscle for hepatic and renal gluconeogenesis.

Rubrosterone is a metabolite of insect metamorphosing substances, that can be isolated from Achyranthes rubrofuca and A. fmaiei (Amaranthaceae).

Mesoxalic acid is primarily located in the cytoplasm within the cell. Mesoxalic acid can be biosynthesized from malonic acid. Outside of the human body mesoxalic acid can be found in cereals and cereal products common pea and herbs and spices.