Taking too much can lead to unpleasant digestive issues, something Ive personally experienced
Anesthesiology 125:133146 Zhang X, Liu S, MG P, Newport GD, Callicott R, Berridge MS, Apana SM, Jr SW, C W (2013) Protective effects of acetyl l-carnitine on inhalation anesthetic-induced neuronal damage in the nonhuman primate
[sources 16] Amphetamine is known to strongly induce cocaine- and amphetamine-regulated transcript (CART) gene expression, [22] [218] a neuropeptide involved in feeding behavior, stress, and reward, which induces observable increases in neuronal development and survival in vitro
"Glutathione Synthesis and Diet," Robb Wolf: Revolutionary Solutions to a Modern Life, under Silvagno, Vernone, Pescarmona