METHODS AND COMPOSITIONS FOR STIMULATING THE GROWTH OF HAIR ARE DISCLOSED WHEREIN SAID COMPOSITIONS INCLUDE A CYCLOPENTANE HEPTANOIC ACID, 2-CYCLOALKYL OR ARYLALKYL COMPOUND REPRESENTED BY THE FORMULA I WHEREIN THE DASHED BONDS REPRESENT THE PRESENCE OR ABSENCE OF A DOUBLE BOND WHICH CAN BE IN THE CIS OR TRANS CONFIGURATION AND A, B, Z, X, R1 AND R2 ARE AS DEFINED IN THE SPECIFICATION AND A PENETRATION ENHANCER. SUCH COMPOSITIONS ARE USED IN STIMULATING HAIR GROWTH OF HUMAN OR NON-HUMAN ANIMALS.