In the present study we assessed the effects of ipriflavone in the prevention of increased bone turnover and the rapid bone loss that follows medical induced hypogonadism caused by the administration of a gonadotropin hormone-releasing hormone agonist (GnRH-A). In a double blind, placebo-controlled study, ipriflavone (600 mg/day, tdd (three divided doses)) or identical placebo tablets were given with 500 mg/day of calcium to patients treated with 3.75 mg leuproreline acetate every 30 days, for 6 months. In placebo-treated subjects (n = 39), urinary hydroxyproline excretion and plasma bone GLA protein levels showed a substantial (P < 0.01) increase, while spine bone density and total body bone density significantly (P < 0.01) decreased after 3 and 6 months of GnRH-A administration. Conversely, in ipriflavone treated group (n = 39), no significant difference in bone markers and bone density was evidenced. These data indicate that ipriflavone can restrain the bone remodeling processes and prevent the rapid bone loss that follows medical induced hypogonadism. Thus, ipriflavone administration can be of value in the prevention of osteopenia in women treated with GnRH-A.