It is worth noting that the caffeine componentof the GTE in this study was relatively low (daily dose of less than1.05 mg) compared to other green tea extracts. No obvious sideeffects or discomfort from sympathetic system hyperactivity werenoted in our study. Thus, the weight reduction effect noted in thisstudy seems entirely attributable to the effects of EGCG, which hasbeen proven to increase fat oxidation through the inhibition ofCOMT, an enzyme involved in the degradation of norepinephrine[22,23], and through the regulation of lipid-metabolism-relatedgenes and transcription factor expression [24,25]. One in vivostudy demonstrated EGCG dose-dependent inhibition of lipidaccumulation in maturing preadipocytes [26]. More study is warranted to discover whether dose-dependent effects exist for EGCGin increasing fat oxidation and lipolysis or suppressing fatty acidsynthesis.