However , carnitine supplementation at dosages of ≤ 1000 mg/day ( p = 0.035 ) or equal to 2000 mg/day ( p = 0.013 ) result ed in significant reduction in ALT level , while doses more than 2000 mg/day did not change ALT  significantly .
Carnitine exerts its reducing effect on serum ALT and AST levels only when these aminotransferases are raised or when the duration of supplementation lasts at least 3 months .
Results of the current meta- analysis showed that carnitine supplementation can decrease serum AST and ALT levels significantly , especially when supplementation lasts 3 months or more in patients with elevated serum aminotransferase levels
Acetyl-L-carnitine improves cognitive functions in severe hepatic encephalopathy: a randomized and controlled clinical trial
The aim of this study was to investigate the effects of ALC treatment on cognitive functions in patients with severe hepatic encephalopathy . This was a r and omized , double-blind , placebo-controlled study . 61 patients with severe hepatic encephalopathy were recruited to the study . The 2 groups received either 2 g ALC twice a day ( n = 30 ) or placebo ( n = 30 ) for 90 days . Clinical and laboratory assessment , psychometric tests and automated electroencephalogram ( EEG ) analysis were performed for all patients . At the end of the study period , between the 2 groups we observed a significant difference in Everyday Memory Question naire −23.9 vs 4.4 ( p < 0.001 ) , Logical Memory ( Paragraph recall ) test 22.3 vs 0.7 ( p < 0.001 ) , Trail Making Test A −7.5 vs −2.6 ( p < 0.001 ) , Trail Making Test B −10.5 vs −3.1 ( p < 0.001 ) , Controlled Oral Word Association Test 4.2 vs 0.5 ( p < 0.001 ) , Hooper test 2.6 vs 0.1 ( p < 0.05 ) , Judgement of line orientation 2.8 vs 0.3 ( p < 0.001 ) , Digit Cancellation time −24.5 vs −2.4 ( p < 0.001 ) , NH4 + 30.5 vs 13.5 ( p < 0.001 ) , prothrombin time 2 vs 2.4 ( p < 0.05 ) , alanine transaminase −10.7 vs −13.6 ( p < 0.001 ) . 88 % of patients treated with ALC vs 72 % of patients treated with placebo  showed a significant improvement in EEG . The improvement of cognitive deficits , the reduction of ammonia , and the modification of EEG in patients treated with ALC suggest that ALC could represent a new tool in the treatment of severe hepatic encephalopathy
However , carnitine supplementation at dosages of ≤ 1000 mg/day ( p = 0.035 ) or equal to 2000 mg/day ( p = 0.013 ) result ed in significant reduction in ALT level , while doses more than 2000 mg/day did not change ALT  significantly .
Carnitine exerts its reducing effect on serum ALT and AST levels only when these aminotransferases are raised or when the duration of supplementation lasts at least 3 months .
Results of the current meta- analysis showed that carnitine supplementation can decrease serum AST and ALT levels significantly , especially when supplementation lasts 3 months or more in patients with elevated serum aminotransferase levels