acetyl l carnitine transport saturated fatty acids The Shuttle. The figure highlights the major components of Carnitine shuttle - Wikipedia

While this is the form your body uses, taking it in a standard pill form still subjects it to the digestive breakdown mentioned above

Side effects may include drowsiness, somnolence, lightheadedness, dry mouth, and a fast heart rate

In contrast to these reports, a later study by Forman et al., 76 found only modest reductions in IgA+ B cell numbers for the small intestine, and no difference for the large intestine

Pharm Chem J 50:281295 Kumar A, Akhtar A, Kuhad A, Sah SP (2023) Sarcosine (glycine transporter inhibitor) attenuates behavioural and biochemical changes induced by ketamine, in the rat model of schizophrenia