The low energy form NAD⁺ shown at left is raised to the high energy form NADH. The change in the form of the active nicotinamide group in NADH is indicated above. It accepts two electrons and a hydrogen in reaching the high energy state. The NAD⁺ is used in redox reactions in the cell and acts as a reducing agent. NADH contributes to oxidation in cell processes like glycolysis to help with the oxidation of glucose.

Nicotinamide adenine dinucleotide phosphate or NADPH is a reduced coenzyme that plays a key role in the synthesis of carbohydrates in photosynthetic organisms. It is the reduced form of NADP⁺ and as such is a high energy molecule that helps drive the Calvin cycle. NADPH is formed during photosynthesis with the use of light energy in the electron transport chain of chloroplasts. It then represents an energy currency that can be used in the Calvin cycle and subsequent reactions to produce carbohydrates.