Research shows that serotonin has a profound effect on mood, can i order generic singulair without rx influencing our feelings of well-being and can i order generic singulair without rx happiness. Zoloft helps make more serotonin available to the brain by slowing down its absorption (along with other selective serotonin reuptake inhibitors). It is important to note that Zoloft doesn't actually increase serotonin levels in the brain.