L-ornithine, α-citrulline, β-alanine, and γ-aminobutyrate, are non-protein amino acids.

L-ornithine and α-citrulline

Both play an important role in metabolic intermediate of urea cycle.

β-alanine – isomer of alanine – vitamin pantothenic acid

Creatinine – plays an important role in energy storage process.

γ-aminobutyrate – free from brain.