If you are taking n-acetyl-l-cysteine or lipoic acid you should stop immediately. N-acetyl-l-cysteine and lipoic acid increase L-cysteine levels by reducing cystine to L-cysteine. Cystine, however, has to enter cells via the cystine/glutamate antiporter so l-glutamate can be transported out. Any supplement that decreases cystine levels is very, very dangerous. Blocking the cystine/glutamate antiporter induces ferroptosis which can kill cells.