Serotonin

Mood control. Scientists have determined that specific serotonin receptors in your brain might be responsible for specific moods.

Depression and irritability. Low serotonin in the brain can lead you to be frustrated more quickly than you used to be. A lack of serotonin also depletes your energy so you’re quickly wiped out. When you do things that used to give you pleasure, you might find they don’t give you a boost like they did in the past.