Liquid Stane (Aromasin) is a strong aromatase-inactivator. It acts as a false substrate for the aromatase enzyme, and is processed to an intermediate that binds irreversibly to the active site of the enzyme causing its inactivation. Liquid Stane significantly lowers circulating estrogen concentrations in subjects. Daily doses of Liquid Stane up to 25mg have no significant effect on circulating levels of testosterone, androstenedione, and dehydroepiandrosterone. Slight, non-dose dependent increases in serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels have been observed even at low doses as a consequence of feedback at the pituitary level.

Aromatase-inactivity can be beneficial to subjects. Estrogen related effects in subjects, such as gyno, acne, or water-retention, brought on by aromatizing agents are suppressed significantly with this aggressive therapy.