The short answer: commercial L-Carnitine is almost certainly halal it is synthetic or fermentation-derived, and meat extraction from commercial production stopped decades ago
10.1016/0026-0495(92)90061-E Ishikura H, Matsuo N, Matsubara M, Ishihara T, Takeyama N, Tanaka T: Valproic acid overdose and L-carnitine therapy
GraziosiAPellegrinoNDi StefanoVRaucciULuchettiAParisiet al
Inhaled glutathione skips that journey entirely." Physician note, Calibrate IV formulation team The problem with swallowing antioxidants Glutathione is often called the body's master antioxidant a tripeptide molecule found in nearly every cell, responsible for neutralizing free radicals, supporting detoxification, and maintaining immune function
Chen D, et al
It is not known to be toxic and does not interact negatively with other medications