I have a couple of questions about using borax for arthritis. I know it raises estradiol in women. I use natural progesterone, estriol, and estradiol creams. I have lessened the doses of estriol and estradiol since using the borax but worry it may still be raising estrogen too high. Maybe the progesterone helps offset that. I also wonder if taking borax without natural progesterone could raise the chance of getting breast cancer in women.