Clinical trials testing estriol for the treatment of multiple sclerosis show great promise…but the FDA is threatening to ban the only way patients can access this critical medicine. Action Alert! Estriol is one of three main estrogens produced by the body, alongside estrone and estradiol. It is often used by integrative practitioners for its benefits to menopausal women, but recent investigations show that it may be effective in the treatment of multiple sclerosis (MS). Despite these health benefits, the FDA is poised to eliminate access to estriol and other bioidentical hormones made at compounding pharmacies. Read more.