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
A randomised, double-blind, placebo-controlled trial of L-carnitine in suspected acute myocardial infarction.
In a r and omised , double-blind placebo-controlled trial , the effects of the administration of oral L-carnitine ( 2 g/day ) for 28 days were compared in the management of 51 ( carnitine group ) and 50 ( placebo group ) patients with suspected acute myocardial infa rct ion . At study entry , the extent of cardiac disease , cardiac enzymes and lipid peroxides were comparable between the groups , although both groups showed an increase in cardiac enzymes and lipid peroxides . At the end of the 28-day treatment period , the mean infa rct size assessed by cardiac enzymes showed a significant reduction in the carnitine group compared to placebo . Electrocardiographic assessment of infa rct size revealed that the QRS-score was significantly less in the carnitine group compared to placebo ( 7.4 + /- 1.2 vs 10.7 + /- 2.0 ) , while serum aspartate transaminase and lipid peroxides showed significant reduction in the carnitine group . Lactate dehydrogenase measured on the sixth or seventh day following infa rct ion showed a smaller rise in the carnitine group compared to placebo . Angina pectoris ( 17.6 vs 36.0 % ) , New York Heart Association class III and IV heart failure plus left ventricular enlargement ( 23.4 vs 36.0 % ) and total arrhythmias ( 13.7 vs 28.0 % ) were significantly less in the carnitine group compared to placebo . Total cardiac events including cardiac deaths and nonfatal infa rct ion were 15.6 % in the carnitine group vs 26.0 % in the placebo group . It is possible that L-carnitine supplementation in patients with suspected acute myocardial infa rct ion may be protective against cardiac necrosis and complications during the first 28 days
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