Desvenlafaxine fumarate is a specialty chemical and active pharmaceutical ingredient (API), specifically a selective serotonin and norepinephrine reuptake inhibitor (SNRI), used primarily in the treatment of major depressive disorder (MDD). It works by increasing the levels of serotonin and norepinephrine in the brain, which helps improve mood and reduce anxiety. This compound is prescribed for adults experiencing persistent feelings of sadness, hopelessness, or lack of interest in daily activities. It is also effective in managing symptoms of generalized anxiety disorder (GAD). The extended-release formulation of derived medications allows for once-daily dosing to enhance patient compliance. Off-label uses may include chronic pain or menopausal symptoms, though these are less common. As a reagent, it is supplied at high purity (≥98%) for pharmaceutical research and manufacturing. Patients or users are monitored for side effects such as nausea, dizziness, or insomnia, with dosage adjustments based on individual response.