Carnitine

Researchers have found tantalizing evidence that bacteria inside the body convert carnitine into a compound that hardens arteries, contributing to arteriosclerosis and increasing the risk of heart attack.

Although often called an amino acid because of its chemical makeup, L-carnitine is actually a vitaminlike nutrient, related in structure to the B vitamins. L-carnitine is the biologically active form of carnitine.

2014, Peggy R. Borum, Carnitine homeostasis in humans, Benjamin Toby Wall, Craig Porter (editors), Carnitine Metabolism and Human Nutrition, page 4, Carnitine likely functions in maintaining homeostasis in many metabolic pathways and physiological conditions, with carnitine's role in energy metabolism homeostasis being the best studied.

Carnitines are quaternary amines synthesized from the amino acids lysine and methionine.