Intrauterine growth retardation (IUGR) contributes to the increased incidence of metabolic syndromes in adulthood, yet the mechanisms underlying lipid metabolism disorders in IUGR pigs remain poorly understood. This study aims to elucidate the mechanism of lipid metabolism disorder in IUGR pigs and the potential alleviating effects of dimethylglycine sodium salt (DMG-Na). A total of 60 male newborn piglets were selected for this study. Within each litter, 1 normal birth weight (NBW) male piglet (1.53 ± 0.04 kg) and 2 IUGR male piglets (0.76 ± 0.06 kg) were chosen based on their birth weight. The piglets were divided into three groups for the study: NBW pigs received a PBS gavage and a common basal diet (NBW-C group), IUGR pigs received the same PBS gavage and common basal diet (IUGR-C group), and IUGR pigs received a 70 mg DMG-Na gavage along with a common basal diet supplemented with 0.1% DMG-Na (IUGR-D group). At 150 d of age, all piglets underwent euthanasia by exsanguination following electrical stunning, after which plasma, liver, and longissimus dorsi (LM) samples were promptly collected. Compared to the NBW-C group, the IUGR-C group exhibited worse (P < 0.05) plasma parameters and hormone levels, as well as disruptions (P < 0.05) in lipid metabolism and energy metabolites in the liver and LM. Additionally, meat quality and expressions of lipid metabolism and mitochondrial function-related genes and proteins were adversely affected (P < 0.05). Conversely, the IUGR-D group demonstrated improved (P < 0.05) plasma parameters and hormone levels, as well as restoration (P < 0.05) of lipid metabolism and energy metabolites in the liver and LM, along with enhanced (P < 0.05) meat quality and expressions of lipid metabolism and mitochondrial function-related genes and proteins compared to the IUGR-C group. In conclusion, it was indicated that IUGR pigs experienced lipid metabolism disorders and diminished performance. However, supplementation with DMG-Na showed promise in mitigating these adverse physiological effects by safeguarding body tissues and modulating energy metabolism.