The small-molecule peptides in the earthworm protein hydrolysate alleviated lipid metabolism disorders in steatotic hepatocytes by regulating the expression levels of crucial proteins (APOC3, HMGCR, PCSK9, PPAR-Y, SREBP1, C/EBP-a, NPC1L1, CYP7A1). This evidence concerns the gene PCSK9 and Disorder of lipid metabolism.