Glutamine
Glutamine is the most abundant naturally occurring, nonessential amino acid in the human body, and one of the few amino acids that can directly cross the blood–brain barrier. Humans obtain glutamine through catabolism of proteins in foods they eat. In states where tissue is being built or repaired, like growth of babies, or healing from wounds or severe illness, glutamine becomes conditionally essential.
Alpha-Ketovaleric acid
α-Ketovaleric acid is a keto acid that is found in human blood. Unlike related keto acids, it is not an intermediate or metabolite associated with amino acids and its origin is unknown.