The use of estradiol alone thinns the hair,since another hormone,progesterone, is responsible for supporting the hair, which makes the hair thicker, estradiol has an antagonism with progesterone.I was convinced of this!I started taking progesterone and my hair started to feel different after getting the progesterone, it started to spike like wheat!Estradiol should only be used with progesterone!If you use estradiol separately, it begins to thin the hair,as estradiol antagonizes with natural progesterone.And gradually the concentration of progesterone begins to fall and the hair that was once more different becomes thinned.