Abstract: A pharmaceutical preparation adhering to the skin, in particular a transdermal therapeutic system, for the release of the active substance 17-&bgr;-estradiol, contained therein in dissolved form being between its saturation concentration in equilibrium with a gas phase of less than 10% relative air humidity and its saturation concentration in equilibrium with a gas phase of more than 90% relative air humidity, in all matrix levels and, if present, also in an adhesive layer, characterized in that the estradiol quantity contained in in the preparation amounts to at least three times the saturation solubility measured at 95% relative air humidity, and that the air enclosed in the package is adjusted to a relative air humidity between 5% and below 0.5%.