Daily oral intake of 70 mg of the soy isoflavone extract Phytosoya for 12 months is safe for the endometrium, according to the results of a study involving 395 postmenopausal women. The results suggest that the agent is a safe alternative or supplement to hormone therapy for the amelioration of climacteric symptoms.

Researchers from France reviewed 301 biopsies from the women; 99.67% were determined to be atrophic/inactive and 0.33% were proliferative. No case of hyperplasia or carcinoma was diagnosed, and no increase in endometrial thickness was noted. Eight women reported some kind of bleeding as an adverse event during the study.

Palacios S, Pornel B, Bergeron C, et al. Endometrial safety assessment of a specific and standardized soy extract according to international guidelines. 