1. Carnitin Carnitine is a salt that is easily soluble in water and is a type of amine. Carnitine is basically divided into two forms: L-carnitine and D-carnitine, but it is L-carnitine that is physically active. D-carnitine is commonly referred to as L-carnitine, as a potential negative role has been reported to undermine the in vivo response of L-carnitine. L-carnitine is an amino acid similar..