Cymbalta is a serotonin-norepinephrine reuptake inhibitor. That means the increase the levels of two neurotransmitters in the brain that are known to play an important part in mood.

When there is not enough serotonin in the brain, the result is depression.

When the is not enough norepinepherine in the brain, the result is a decrease in mood and energy.

Serotonin is a monoamine neurotransmitter, meaning it contains only one amino group that is connected to an aromatic ring by a two-carbon chain.

About 80 to 90 percent of the human body’s serotonin is located in the enterochomaffin cells in the gut, where it is used to regulate intestinal movement. The remainder is found in the central nervous system.

Norepinepherine is a sympathomimetic “fight or flight” hormone released by the adrenal glands in response to stress with duel roles as a hormone and a neurotransmitter.

As a stress hormone norepinepherine affects parts of the brain where attention and responding actions are controlled.