CRAT and systemic primary carnitine deficiency disease: D-carnitine without bioactivities in people, however, has adverse biological effects via suppressing the carnitine acetyltransferase (23), with supplementation of D-carnitine inducing oxidative stress, liver inflammation, and apoptosis in animal studies (24), causing secondary carnitine deficiency, and therefore, almost no human studies of D-carnitine have been conducted (21).