The glucocorticosteroids, (1) fluocinolone (F), (2) fluocinolone acetonide (FA), (3) fluocinolone acetonide acetate (FAA), (4) betamethasone 17-valerate (BV), and (5) betamethasone (B) were tested for vasoconstrictor potency in vivo and ability to penetrate human and hairless mouse skin in vitro. BV and B penetrate skin at the same rate but are different by over 100-fold with regard to vasoconstrictor potency. FA penetrates skin better than F and is also more potent as a vasoconstrictor. FAA is superior to FA in vasoconstriction but about the same in ability to penetrate skin.