HRT, consisting of systemic treatment with estrogen alone or in combination with a progestogen, has well-documented and considerable beneficial effects on the skin of postmenopausal women.   These benefits include increased skin collagen content, skin thickness and elasticity, and skin hydration and surface lipids.   Topical estrogen has been found to have similar beneficial effects on the skin.  In addition, a study has found that topical 2% progesterone cream significantly increases skin elasticity and firmness and observably decreases wrinkles in peri- and postmenopausal women.  Skin hydration and surface lipids, on the other hand, did not significantly change with topical progesterone.  These findings suggest that progesterone, like estrogen, also has beneficial effects on the skin, and may be independently protective against skin aging.