This research was conducted to study the effects of supplemental L-Methionine (L-Met) and DL-Methionine (DL-Met) on nutrient metabolism, muscle gene expression, and growth performance of pigs. Twenty crossbred young barrows (initial Body Weight (BW) 21.2 ± 2.7 kg) were randomly assigned to 2 treatments. Crystalline L-Met and DL- Met were supplemented to the diets in Treatment 1 and 2 (both at 0.13%, ased basis), respectively. After 4 weeks of an ad libitum feeding trial, BW and feed intake were measured to calculate Average Daily Gain, Average Daily Feed Intake, and Gain: Feed. The blood samples were collected from the jugular vein for analyses of plasma AA and metabolite concentrations. The longissimus dorsi muscle samples were collected for analysis of myogenesis gene expression. The findings from this study (from gene expression to animal growth performance) suggest that the bioefficacy of L-Met is the same as for DL-Met, indicating the highly efficient conversion of D-Met to L-Met in young growing barrows.