Endergonic reaction
![An endergonic reaction (such as photosynthesis) is a reaction that requires energy to be driven. Endergonic (from the prefix endo-, derived from the Greek word ἔνδον endon,](/Images/godic/202501/11/Endergonic_Reaction.svg3700.png")
In chemical thermodynamics, an endergonic reaction (also called a nonspontaneous reaction or an unfavorable reaction) is a chemical reaction in which the standard change in free energy is positive, and energy is absorbed. In layman's terms, the total amount of energy is a loss (it takes more energy to start the reaction than what you get out of it) so the total energy is a negative net result. For an overall gain in the net result see exergonic reaction.