Arzoxifene hydrochloride is a selective estrogen receptor modulator that is a potent estrogen antagonist in mammary and uterine tissue.

Arzoxifene inhibits cell growth as effectively as the antiestrogen tamoxifen. Arzoxifene exerts a statistically significant inhibition of pS2 and progesterone receptor B mRNA expression. A significant agonistic effect is observed in the antitrypsin mRNA expression. In contrast to estradiol and tamoxifen, arzoxifene does not upregulate cathepsin D mRNA and protein expression.

Arzoxifene prevents the ovariectomy-induced increase in body weight and serum cholesterol levels of treated rats and lowers them to below sham levels in a dose-dependent manner, with maximum efficacy similar to estrogen or raloxifene. Arzoxifene prevents loss of bone due to ovariectomy with maximal efficacy observed at 0.1-1 mg/kg/day ( ED50: about 0.01 mg/kg). Arzoxifene antagonizes the estrogen-induced elevation in uterine weight down to vehicle-dosed control levels (ED50: 0.03 mg/kg/day).