Methods and compositions for stimulating the growth of hair are disclosed wherein emulsions include a cyclopentane heptanoic acid, 2-cycloalkyl or arylalkyl compound represented by the formula I wherein the dashed bonds represent a single or double bond which can be in the cis or trans configuration, A, B, Z, X, R and R are as defined in the specification. Such compositions are used in treating the skin or scalp of a human or non-human animal.
