Previous studies have shown that L-theanine can decrease the expression of FASN and ACC1 in the liver of normal rats [15], and the mRNA expression in HFD-induced liver [17], Our results showed that L-theanine effectively decreased the mRNA and protein expression of FASN, ACC1 and PPARγ in steatosis liver in vitro and in vivo. Here, PPARG is linked to steatosis.