Citrulline is combined with Malic Acid to form Citrulline Malate. The amino acid Citrulline occurs in watermelon (Citrullus lanatus), while Malic Acid is an organic acid that is abundant in nature (e.g. in fruits). Many proteins contain Citrulline and both ingredients are key intermediates in metabolic cycles.
Supplementation with Citrulline Malate is popular with athletes and bodybuilders that follow tough workout regimes.