The drug works in two phases: initially, upon administration, it stimulates the pituitary gland to release increased LH and FSH, temporarily raising sex hormone levels — a "flare-up" effect. With continuous administration, however, the pituitary's GnRH receptors become desensitized, leading to a sustained drop in testosterone (in men) or estrogen (in women), which slows or stops the growth of hormone-dependent cancer cells.
The injection is formulated as a biodegradable depot implant, delivered subcutaneously — typically into the abdominal wall — providing a consistent therapeutic drug level over the treatment interval, administered by a trained healthcare professional. Patients may experience a reduction in bone mineral density with prolonged use, and doctors may prescribe additional medication to reduce bone loss. Mood changes, including feelings of depression or disturbing thoughts, should be reported to the treating physician, and some women may experience vaginal bleeding in the first month of treatment, which typically resolves on its own.