Hydroxypyruvic acid lithium hydrate is an intermediate in the metabolism of serine, glycine, and threonine. It is a substrate for serine-pyruvate aminotransferase and glyoxylate reductase/hydroxypyruvate reductase.

Hydroxypyruvic acid ?(intravenous injection;?100 mg/ml;?slowly over 10 min) increases the 5-h urinary oxalate and glycolate excretion to 0.68% (6.56 μmol) and 0.53% (5.10 μmol) in control rats, in addition, it increases to 2.43% (23.36 μmol) and 0.79% (7.59 μmol) of the dose in the vitamin-B6-deficient rats.