Abstract: The present approach relates to compositions and methods for treating fingernails, toenails, hoofs, claws and the like, in mammals. More particularly, the present approach relates to compositions and methods including a prostaglandin analog active ingredient and a carrier. The compositions and methods may be used for increasing the thickness, strength, integrity, length and/or growth rate of human nails, or both, and promoting healthy nail growth and appearance, as well as relates to compositions and methods for increasing the thickness or strength of horny parts of mammals, and promoting healthy nail, claw and hoof growth.