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, demonstrating statistically significant inhibition of pS2 and progesterone receptor B mRNA expression along with a significant agonistic effect on antitrypsin mRNA expression. Unlike estradiol and tamoxifen, arzoxifene does not upregulate cathepsin D mRNA and protein expression.

Arzoxifene counteracts the ovariectomy-induced increase in body weight and serum cholesterol in treated rats, effectively reducing them below sham levels in a dose-dependent manner, with maximum efficacy comparable to estrogen or raloxifene. It prevents bone loss due to ovariectomy, showing maximal efficacy at 0.1-1 mg/kg/day [ED50: approximately 0.01 mg/kg]. Additionally, arzoxifene mitigates the estrogen-induced rise in uterine weight to vehicle-dosed control levels [ED50: 0.03 mg/kg/day].