Summary of proposed mechanisms of common ingredients in thermogenic products. adenylate cyclase (AC), adenosine monophosphate (AMP), 3,5-cyclic-adenosine monophosphate (cAMP), 5′adenosine monophosphate-activated protein kinase (AMPK), adenosine triphosphate (ATP), catechol O-methyltransferase (COMT), cAMP-related element binding protein (CREB), epigallocatechin gallate (EGCG), G-coupled protein receptor (G-CPR), prostaglandin (PG), protein kinase A (PKA), norepinephrine (NE), and phosphodiesterase (PDE).